Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 1

TCPIP and Other Transports for High Bandwidth Applications

Back to Basics

Richard Hughes-Jones The University of Manchester

wwwhepmanacuk~rich then ldquoTalksrdquo then look for ldquoBrasovrdquo

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 2

The aim is to give you a picture of how researchers are using high performance networks to support their work

Back to Basics Simple Introduction to Networking

TCPIP on High Bandwidth Long Distance Networks But TCPIP works

The effect of packet loss Advanced TCP Stacks Fairness

Real Applications on Real Networks Disk-2-disk applications on real networks

Memory-2-memory testsTransatlantic disk-2-disk at Gigabit speeds

Remote Computing FarmsThe effect of distance

Radio Astronomy e-VLBI

Thanks for allowing me to use their slides to Sylvain Ravot CERN Les Cottrell SLAC Brian Tierney LBL Robin Tasker DL

Structure of the Talks

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 3

Simple Introduction to Networking

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 4

What is a Protocol Stack ISO OSI (Open Systems Interconnection) Seven Layer Model defines a

framework allowing development of real network protocols A layerhellip

performs unique and specific tasks only has knowledge of those layers immediately above and below uses services of layer below and provides services to layer above the services defined by a layer are implementation independent ndash

itrsquos a definition of how things work conceptually communicates with its peer in the remote system

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 5

The Layering Principle Encapsulation

Each protocol layer N adds a Header to the data unit from layer N+1 Header contains control information

Layer 7 Applicationuser processes

Layer 6 Presentationdata interpretation code transformation

Layer 5 SessionConnection negotiation control

Layer 4 TransportEnd-2-end data transfer amp integrityPacket sequencing flow control

Layer 3 NetworkAddressing RoutingPacket sequencing flow control

Layer 2 Data LinkPacket assemblydisassembly Transmission control Error checking

Layer 1 PhysicalElectrical Optical Mechanical

DH App data FCSNH TH PHSH

App data NH TH PHSH

App data TH PHSH

App data PHSH

App data PH

App data

Bits on the ldquowirerdquo

Frame

Packet

Segment

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 6

What do the Layers do Transport Layer acts as a go-between for the user and network

Provides end-to-end data movement amp control Gives the level of reliabilityintegrity need by the application Can ensure a reliable service (which network layer cannot)

eg assigns sequence numbers to identify ldquolostrdquo packets Network Layer deals with logical addressing amp the transmission of

packets mechanism for routing Data Link Layer provides the synchronization and error checking for

the data transmitted over a single physical link (may ensure correct delivery of frames) 1048708Going down fits packets from the network layer above into

frames 1048708Going up Groups bits from the physical layer into frames

Physical Layer concerned with the transmission of individual bits

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 2

The aim is to give you a picture of how researchers are using high performance networks to support their work

Back to Basics Simple Introduction to Networking

TCPIP on High Bandwidth Long Distance Networks But TCPIP works

The effect of packet loss Advanced TCP Stacks Fairness

Real Applications on Real Networks Disk-2-disk applications on real networks

Memory-2-memory testsTransatlantic disk-2-disk at Gigabit speeds

Remote Computing FarmsThe effect of distance

Radio Astronomy e-VLBI

Thanks for allowing me to use their slides to Sylvain Ravot CERN Les Cottrell SLAC Brian Tierney LBL Robin Tasker DL

Structure of the Talks

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 3

Simple Introduction to Networking

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 4

What is a Protocol Stack ISO OSI (Open Systems Interconnection) Seven Layer Model defines a

framework allowing development of real network protocols A layerhellip

performs unique and specific tasks only has knowledge of those layers immediately above and below uses services of layer below and provides services to layer above the services defined by a layer are implementation independent ndash

itrsquos a definition of how things work conceptually communicates with its peer in the remote system

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 5

The Layering Principle Encapsulation

Each protocol layer N adds a Header to the data unit from layer N+1 Header contains control information

Layer 7 Applicationuser processes

Layer 6 Presentationdata interpretation code transformation

Layer 5 SessionConnection negotiation control

Layer 4 TransportEnd-2-end data transfer amp integrityPacket sequencing flow control

Layer 3 NetworkAddressing RoutingPacket sequencing flow control

Layer 2 Data LinkPacket assemblydisassembly Transmission control Error checking

Layer 1 PhysicalElectrical Optical Mechanical

DH App data FCSNH TH PHSH

App data NH TH PHSH

App data TH PHSH

App data PHSH

App data PH

App data

Bits on the ldquowirerdquo

Frame

Packet

Segment

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 6

What do the Layers do Transport Layer acts as a go-between for the user and network

Provides end-to-end data movement amp control Gives the level of reliabilityintegrity need by the application Can ensure a reliable service (which network layer cannot)

eg assigns sequence numbers to identify ldquolostrdquo packets Network Layer deals with logical addressing amp the transmission of

packets mechanism for routing Data Link Layer provides the synchronization and error checking for

the data transmitted over a single physical link (may ensure correct delivery of frames) 1048708Going down fits packets from the network layer above into

frames 1048708Going up Groups bits from the physical layer into frames

Physical Layer concerned with the transmission of individual bits

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 3

Simple Introduction to Networking

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 4

What is a Protocol Stack ISO OSI (Open Systems Interconnection) Seven Layer Model defines a

framework allowing development of real network protocols A layerhellip

performs unique and specific tasks only has knowledge of those layers immediately above and below uses services of layer below and provides services to layer above the services defined by a layer are implementation independent ndash

itrsquos a definition of how things work conceptually communicates with its peer in the remote system

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 5

The Layering Principle Encapsulation

Each protocol layer N adds a Header to the data unit from layer N+1 Header contains control information

Layer 7 Applicationuser processes

Layer 6 Presentationdata interpretation code transformation

Layer 5 SessionConnection negotiation control

Layer 4 TransportEnd-2-end data transfer amp integrityPacket sequencing flow control

Layer 3 NetworkAddressing RoutingPacket sequencing flow control

Layer 2 Data LinkPacket assemblydisassembly Transmission control Error checking

Layer 1 PhysicalElectrical Optical Mechanical

DH App data FCSNH TH PHSH

App data NH TH PHSH

App data TH PHSH

App data PHSH

App data PH

App data

Bits on the ldquowirerdquo

Frame

Packet

Segment

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 6

What do the Layers do Transport Layer acts as a go-between for the user and network

Provides end-to-end data movement amp control Gives the level of reliabilityintegrity need by the application Can ensure a reliable service (which network layer cannot)

eg assigns sequence numbers to identify ldquolostrdquo packets Network Layer deals with logical addressing amp the transmission of

packets mechanism for routing Data Link Layer provides the synchronization and error checking for

the data transmitted over a single physical link (may ensure correct delivery of frames) 1048708Going down fits packets from the network layer above into

frames 1048708Going up Groups bits from the physical layer into frames

Physical Layer concerned with the transmission of individual bits

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 4

What is a Protocol Stack ISO OSI (Open Systems Interconnection) Seven Layer Model defines a

framework allowing development of real network protocols A layerhellip

performs unique and specific tasks only has knowledge of those layers immediately above and below uses services of layer below and provides services to layer above the services defined by a layer are implementation independent ndash

itrsquos a definition of how things work conceptually communicates with its peer in the remote system

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 5

The Layering Principle Encapsulation

Each protocol layer N adds a Header to the data unit from layer N+1 Header contains control information

Layer 7 Applicationuser processes

Layer 6 Presentationdata interpretation code transformation

Layer 5 SessionConnection negotiation control

Layer 4 TransportEnd-2-end data transfer amp integrityPacket sequencing flow control

Layer 3 NetworkAddressing RoutingPacket sequencing flow control

Layer 2 Data LinkPacket assemblydisassembly Transmission control Error checking

Layer 1 PhysicalElectrical Optical Mechanical

DH App data FCSNH TH PHSH

App data NH TH PHSH

App data TH PHSH

App data PHSH

App data PH

App data

Bits on the ldquowirerdquo

Frame

Packet

Segment

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 6

What do the Layers do Transport Layer acts as a go-between for the user and network

Provides end-to-end data movement amp control Gives the level of reliabilityintegrity need by the application Can ensure a reliable service (which network layer cannot)

eg assigns sequence numbers to identify ldquolostrdquo packets Network Layer deals with logical addressing amp the transmission of

packets mechanism for routing Data Link Layer provides the synchronization and error checking for

the data transmitted over a single physical link (may ensure correct delivery of frames) 1048708Going down fits packets from the network layer above into

frames 1048708Going up Groups bits from the physical layer into frames

Physical Layer concerned with the transmission of individual bits

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 5

The Layering Principle Encapsulation

Each protocol layer N adds a Header to the data unit from layer N+1 Header contains control information

Layer 7 Applicationuser processes

Layer 6 Presentationdata interpretation code transformation

Layer 5 SessionConnection negotiation control

Layer 4 TransportEnd-2-end data transfer amp integrityPacket sequencing flow control

Layer 3 NetworkAddressing RoutingPacket sequencing flow control

Layer 2 Data LinkPacket assemblydisassembly Transmission control Error checking

Layer 1 PhysicalElectrical Optical Mechanical

DH App data FCSNH TH PHSH

App data NH TH PHSH

App data TH PHSH

App data PHSH

App data PH

App data

Bits on the ldquowirerdquo

Frame

Packet

Segment

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 6

What do the Layers do Transport Layer acts as a go-between for the user and network

Provides end-to-end data movement amp control Gives the level of reliabilityintegrity need by the application Can ensure a reliable service (which network layer cannot)

eg assigns sequence numbers to identify ldquolostrdquo packets Network Layer deals with logical addressing amp the transmission of

packets mechanism for routing Data Link Layer provides the synchronization and error checking for

the data transmitted over a single physical link (may ensure correct delivery of frames) 1048708Going down fits packets from the network layer above into

frames 1048708Going up Groups bits from the physical layer into frames

Physical Layer concerned with the transmission of individual bits

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 6

What do the Layers do Transport Layer acts as a go-between for the user and network

Provides end-to-end data movement amp control Gives the level of reliabilityintegrity need by the application Can ensure a reliable service (which network layer cannot)

eg assigns sequence numbers to identify ldquolostrdquo packets Network Layer deals with logical addressing amp the transmission of

packets mechanism for routing Data Link Layer provides the synchronization and error checking for

the data transmitted over a single physical link (may ensure correct delivery of frames) 1048708Going down fits packets from the network layer above into

frames 1048708Going up Groups bits from the physical layer into frames

Physical Layer concerned with the transmission of individual bits

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 7

How do the ldquoIPrdquo Protocols fit together

Application

( Presentation

Session)

Transport

Network

Data Link

Physical

FileTransferProtocol

(FTP) RFC 559

Simple MailTransfer Protocol(SMTP) RFC 821

TELNETRFC 854

TFTP RFC 783

NFSRFC 1024 1057

and 1094

SNMPRFC 1157

Transmission Control Protocol (TCP)

RFC 793

User Datagram Protocol (UDP)

RFC 768

Address ResolutionProtocols

ARP RFC 826RARP RFC 903

Internet ProtocolIP

RFC 791

Internet ControlMessage Protocol

(ICMP) RFC 792

Ethernet Token Ring ISDN FDDI SMDS ATM SDHSONET xDSL

Transmission Mode

TP Copper Fibre Optic Satellite Microwave DWDM CWDM etc

Network Interface Cards

RoutingOSPF BGP

ssh

HTTP POP3IMAP

DNS

DNS

ping

traceroute

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 8

Some of the ldquoIPrdquo Protocols Transmission Control Protocol TCP provides application programs

access to the network using a reliable connection-oriented transport layer service

User Datagram Protocol UDP provides unreliable connection-less delivery service using the IP protocol to transport messages between machines It adds the ability to distinguish among multiple destinations on a single host computer

Internet Protocol IP receives datagrams from the upper-layer software and transmits it to the destination host based upon a best effort connection-less delivery service

Internet Control Message Protocol ICMP allows internet routers to transmit error messages and test messages

Internet Group Message Protocol IGMP is used with multicast to send UDP datagrams to multiple hosts

Address Resolution Protocol ARP translates between the 32 bit IP address and a 48 bit LAN address

Reverse Address Resolution Protocol RARP translates between the 48 bit LAN address and the 32 bit IP address

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 9

The Physical Layer 1 Ethernet

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 10

The Link Layer 2 Ethernet Frame

Preamble which is comprised of 56 bits of alternating 0s and 1s The preamble provides all the nodes on the network a signal against which to synchronize

Media Access Control (MAC) AddressEvery Ethernet network card has built into its hardware a unique six-octet (48-bit) hexadecimal number that differentiates it from all other Ethernet cards in the universe The DA and SA define the path across the link

Start Frame delimiter which marks the start of a frame The start frame delimiter is 8 bits long with the pattern10101011

Data the reason the frame exists MTU Maximum Transport Unit

Frame Check Sequence to protect the frame contents

LengthType field two octets longIf the value =lt 1500 (0x05dc hex) indicates the length of dataIf the value gt 1500 indicates network-layer protocol ldquoEthernet Typesrdquo

Frame header IP Datagram FCS

12 bytes

Inter Frame Gap

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 11

The Link Layer Ethernet VLANs

VLANS are logical networks built over the same physical cable plant Distinguishes Ethernet frames betweentheir logical networks using VLANheader

VLAN is defined by the use of value 0x8100 in the Type field location

The next two octets are composed of the following three fields

User Priority field This field is 3 bits in length and is used to define the priority of the Ethernet frame This is utilized to define and deliver a class of service

Canonical format indicator This is 1 bit in length Just donrsquot ask

VLAN Identifier field This field is 12 bits in length and contains the VLAN identifier (VID) of this frame

The original LengthType field will then follow the inserted VLAN tag

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 12

The Network Layer 3 IP IP Layer properties

Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Connection less Provides logical addresses Provides routing Demultiplex data on protocol number

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 13

The Internet datagram

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

20 Bytes

Frame header Transport FCSIP header

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 14

IP Datagram Format (cont) Type of Service ndash TOS

now being used for QoS Total length length of datagram

in bytes includes header and data Time to live ndash TTL specifies how long datagram is

allowed to remain in internet Routers decrement by 1 When TTL = 0 router discards datagram Prevents infinite loops

Protocol specifies the format of the data area Protocol numbers administered by central authority to guarantee

agreement eg ICMP=1 TCP=6 UDP=17 hellip Source amp destination IP address (32 bits each) contain

IP address of sender and intended recipient Options (variable length) Mainly used to record a route

or timestamps or specify routing

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

HlenVers TOS Total length

Identification Flags Fragment offset

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 15

Internet Class-based addresses An Address looks like 19216822123

Class A large number of hosts few networks 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh

7 network bits (0 and 127 reserved so 126 networks) 24 host bits (gt 16M hostsnet)

Initial byte 1-127 (decimal) Class B medium number of hosts and networks

10nnnnnn nnnnnnnn hhhhhhhh hhhhhhhh16384 class B networks 65534 hostsnetworkInitial byte 128-191 (decimal)

Class C large number of small networks 110nnnnn nnnnnnnn nnnnnnnn hhhhhhhh

2097152 networks 254 hostsnetworkInitial byte 192-223 (decimal)

Class D Multicast (See RFC 1112) 1110nnnn nnnnnnnn nnnnnnnn hhhhhhhh

Initial byte 224-239 (decimal) Class E Reserved

Initial byte 248-255 (decimal)

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 16

The Transport Layer 4 UDP UDP Provides

Connection less service over IPNo setup teardownOne packet at a time

Minimal overhead ndash high performance Provides best effort delivery It is unreliable

Packet may be lostDuplicatedOut of order

Application is responsible for Data reliabilityFlow controlError handling

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 17

UDP Datagram format

Sourcedestination port port numbers identify sending amp receiving processes

Port number amp IP address allow any application on Internet to be uniquely identified

Ports can be static or dynamic

Static (lt 1024) assigned centrally known as well known ports

Dynamic

Message length in bytes includes the UDP header and data (min 8 max 65535)

8 16 3124

Source port Destination port

UDP message len Checksum (opt)

0

Frame header Application data FCSIP header UDP header

8 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 18

The Transport Layer 4 TCP TCP RFC 768 RFC 1122 Provides

Connection orientated service over IPDuring setup the two ends agree on detailsExplicit teardownMultiple connections allowed

Reliable end-to-end Byte Stream delivery over unreliable network It takes care of

Lost packets Duplicated packetsOut of order packets

TCP provides Data buffering Flow controlError detection amp handlingLimits network congestion

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 19

Code

Source port Destination port

Sequence number

0 8 16 3124

Acknowledgement number

4

Hlen

10

Resv Window

Urgent ptrChecksum

Options (if any) Padding

The TCP Segment FormatFrame header Application data FCSIP header TCP header

20 Bytes

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 20

TCP Segment Format ndash cont SourceDest port TCP port numbers to ID applications

at both ends of connection Sequence number First byte in segment from senderrsquos

byte stream Acknowledgement identifies the number of the byte the

sender of this segment expects to receive next Code used to determine segment purpose eg SYN

ACK FIN URG Window Advertises how much data this station is willing

to accept Can depend on buffer space remaining Options used for window scaling

SACK timestamps maximum segment size etc

Code

Source port Destination port

Sequence number

Acknowledgement number

Hlen Resv Window

Urgent ptrChecksum

Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 21

Frame header Application data FCSIP header UDP header

The RTP Header Format

RTP header

Sequence Num

RTP Time Stamp

0 8 16 3124

Synchronization Source Identifier

4 12

12 Bytes

CSRCP X M I S TVer VPT

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 22

31HlenVers Type of serv Total length

0 8 16

Identification Flags

244

Fragment offset

19

TTL Protocol Header Checksum

Source IP address

Destination IP address

IP Options (if any) Padding

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 23

Lectures tutorials etc on TCPIP wwwnvccvaushomejoneytcp_iphtm wwwcspdxedu~jrbtcpiplectureshtml wwwraleighibmcomcgi-binbookmgrBOOKSEZ306200CCONTENTS wwwciscocomunivercdcctddocproductiaabucentri4userscf4ap1htm wwwcisohio-stateeduhtbinrfcrfc1180html wwwjbmelectronicscomtcphtm

Encylopaedia httpwwwfreesoftorgCIEindexhtm

TCPIP Resources wwwprivateorgiltcpip_rlhtml

Understanding IP addresses httpwww3comcomsolutionsen_USncs501302html

Configuring TCP (RFC 1122) ftpnicmeriteduinternetdocumentsrfcrfc1122txt

Assigned protocols ports etc (RFC 1010) httpwwwesnetpubrfcsrfc1010txt amp etcprotocols

More Information

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 24

Any Questions

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 25

Backup Slides

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 26

More Information Some URLs UKLight web site httpwwwuklightacuk MB-NG project web site httpwwwmb-ngnet DataTAG project web site httpwwwdatatagorg UDPmon TCPmon kit + writeup

httpwwwhepmanacuk~richnet Motherboard and NIC Tests

httpwwwhepmanacuk~richnetnicGigEth_tests_Bostonpptamp httpdatatagwebcernchdatatagpfldnet2003 ldquoPerformance of 1 and 10 Gigabit Ethernet Cards with Server Quality Motherboardsrdquo FGCS Special issue 2004 http wwwhepmanacuk~rich

TCP tuning information may be found athttpwwwncnenlanrnetdocumentationfaqperformancehtml amp httpwwwpscedunetworkingperf_tunehtml

TCP stack comparisonsldquoEvaluation of Advanced TCP Stacks on Fast Long-Distance Production Networksrdquo Journal of Grid Computing 2004

PFLDnet httpwwwens-lyonfrLIPRESOpfldnet2005 Dante PERT httpwwwgeant2netservershownav00d00h002

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 27

tcpdump tcptrace tcpdump dump all TCP header information for a specified

sourcedestination ftpftpeelblgov

tcptrace format tcpdump output for analysis using xplot httpwwwtcptraceorg NLANR TCP Testrig Nice wrapper for tcpdump and tcptrace tools

httpwwwncnenlanrnetTCPtestrig

Sample use tcpdump -s 100 -w tmptcpdumpout host hostname tcptrace -Sl tmptcpdumpout xplot tmpa2b_tsgxpl

• TCPIP and Other Transports for High Bandwidth Applications Back to Basics
• Slide 2
• Slide 3
• What is a Protocol Stack
• The Layering Principle
• What do the Layers do
• How do the ldquoIPrdquo Protocols fit together
• Some of the ldquoIPrdquo Protocols
• The Physical Layer 1 Ethernet
• The Link Layer 2 Ethernet Frame
• Slide 11
• The Network Layer 3 IP
• The Internet datagram
• IP Datagram Format (cont)
• Internet Class-based addresses
• The Transport Layer 4 UDP
• UDP Datagram format
• The Transport Layer 4 TCP
• The TCP Segment Format
• TCP Segment Format ndash cont
• The RTP Header Format
• Slide 22
• More Information
• Slide 24
• Slide 25
• More Information Some URLs
• tcpdump tcptrace

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 25

Backup Slides

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 26

More Information Some URLs UKLight web site httpwwwuklightacuk MB-NG project web site httpwwwmb-ngnet DataTAG project web site httpwwwdatatagorg UDPmon TCPmon kit + writeup

httpwwwhepmanacuk~richnet Motherboard and NIC Tests

httpwwwhepmanacuk~richnetnicGigEth_tests_Bostonpptamp httpdatatagwebcernchdatatagpfldnet2003 ldquoPerformance of 1 and 10 Gigabit Ethernet Cards with Server Quality Motherboardsrdquo FGCS Special issue 2004 http wwwhepmanacuk~rich

TCP tuning information may be found athttpwwwncnenlanrnetdocumentationfaqperformancehtml amp httpwwwpscedunetworkingperf_tunehtml

TCP stack comparisonsldquoEvaluation of Advanced TCP Stacks on Fast Long-Distance Production Networksrdquo Journal of Grid Computing 2004

PFLDnet httpwwwens-lyonfrLIPRESOpfldnet2005 Dante PERT httpwwwgeant2netservershownav00d00h002

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 27

tcpdump tcptrace tcpdump dump all TCP header information for a specified

sourcedestination ftpftpeelblgov

tcptrace format tcpdump output for analysis using xplot httpwwwtcptraceorg NLANR TCP Testrig Nice wrapper for tcpdump and tcptrace tools

httpwwwncnenlanrnetTCPtestrig

Sample use tcpdump -s 100 -w tmptcpdumpout host hostname tcptrace -Sl tmptcpdumpout xplot tmpa2b_tsgxpl

• TCPIP and Other Transports for High Bandwidth Applications Back to Basics
• Slide 2
• Slide 3
• What is a Protocol Stack
• The Layering Principle
• What do the Layers do
• How do the ldquoIPrdquo Protocols fit together
• Some of the ldquoIPrdquo Protocols
• The Physical Layer 1 Ethernet
• The Link Layer 2 Ethernet Frame
• Slide 11
• The Network Layer 3 IP
• The Internet datagram
• IP Datagram Format (cont)
• Internet Class-based addresses
• The Transport Layer 4 UDP
• UDP Datagram format
• The Transport Layer 4 TCP
• The TCP Segment Format
• TCP Segment Format ndash cont
• The RTP Header Format
• Slide 22
• More Information
• Slide 24
• Slide 25
• More Information Some URLs
• tcpdump tcptrace

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 26

More Information Some URLs UKLight web site httpwwwuklightacuk MB-NG project web site httpwwwmb-ngnet DataTAG project web site httpwwwdatatagorg UDPmon TCPmon kit + writeup

httpwwwhepmanacuk~richnet Motherboard and NIC Tests

httpwwwhepmanacuk~richnetnicGigEth_tests_Bostonpptamp httpdatatagwebcernchdatatagpfldnet2003 ldquoPerformance of 1 and 10 Gigabit Ethernet Cards with Server Quality Motherboardsrdquo FGCS Special issue 2004 http wwwhepmanacuk~rich

TCP tuning information may be found athttpwwwncnenlanrnetdocumentationfaqperformancehtml amp httpwwwpscedunetworkingperf_tunehtml

TCP stack comparisonsldquoEvaluation of Advanced TCP Stacks on Fast Long-Distance Production Networksrdquo Journal of Grid Computing 2004

PFLDnet httpwwwens-lyonfrLIPRESOpfldnet2005 Dante PERT httpwwwgeant2netservershownav00d00h002

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 27

tcpdump tcptrace tcpdump dump all TCP header information for a specified

sourcedestination ftpftpeelblgov

tcptrace format tcpdump output for analysis using xplot httpwwwtcptraceorg NLANR TCP Testrig Nice wrapper for tcpdump and tcptrace tools

httpwwwncnenlanrnetTCPtestrig

Sample use tcpdump -s 100 -w tmptcpdumpout host hostname tcptrace -Sl tmptcpdumpout xplot tmpa2b_tsgxpl

• TCPIP and Other Transports for High Bandwidth Applications Back to Basics
• Slide 2
• Slide 3
• What is a Protocol Stack
• The Layering Principle
• What do the Layers do
• How do the ldquoIPrdquo Protocols fit together
• Some of the ldquoIPrdquo Protocols
• The Physical Layer 1 Ethernet
• The Link Layer 2 Ethernet Frame
• Slide 11
• The Network Layer 3 IP
• The Internet datagram
• IP Datagram Format (cont)
• Internet Class-based addresses
• The Transport Layer 4 UDP
• UDP Datagram format
• The Transport Layer 4 TCP
• The TCP Segment Format
• TCP Segment Format ndash cont
• The RTP Header Format
• Slide 22
• More Information
• Slide 24
• Slide 25
• More Information Some URLs
• tcpdump tcptrace

Summer School Brasov Romania July 2005 R Hughes-Jones Manchester 27

tcpdump tcptrace tcpdump dump all TCP header information for a specified

sourcedestination ftpftpeelblgov

tcptrace format tcpdump output for analysis using xplot httpwwwtcptraceorg NLANR TCP Testrig Nice wrapper for tcpdump and tcptrace tools

httpwwwncnenlanrnetTCPtestrig

Sample use tcpdump -s 100 -w tmptcpdumpout host hostname tcptrace -Sl tmptcpdumpout xplot tmpa2b_tsgxpl

• TCPIP and Other Transports for High Bandwidth Applications Back to Basics
• Slide 2
• Slide 3
• What is a Protocol Stack
• The Layering Principle
• What do the Layers do
• How do the ldquoIPrdquo Protocols fit together
• Some of the ldquoIPrdquo Protocols
• The Physical Layer 1 Ethernet
• The Link Layer 2 Ethernet Frame
• Slide 11
• The Network Layer 3 IP
• The Internet datagram
• IP Datagram Format (cont)
• Internet Class-based addresses
• The Transport Layer 4 UDP
• UDP Datagram format
• The Transport Layer 4 TCP
• The TCP Segment Format
• TCP Segment Format ndash cont
• The RTP Header Format
• Slide 22
• More Information
• Slide 24
• Slide 25
• More Information Some URLs
• tcpdump tcptrace