NETWORK PROTOCOLS &
COMMUNICATIONS
Chapter 3
Intro to Routing & Switching
OBJECTIVES Upon completion of this chapter, you
should be able to:Explain why protocols are necessary in
communicationExplain the role of standards organizations
in establishing protocolsExplain how the TCP/IP model and the OSI
model are used for standardization of communication
Explain how data encapsulation allows data to be transported
Explain how local hosts access local resources
Explain how local hosts access remote resources
WHAT IS COMMUNICATION?
THE RULES
3.1.1
THE RULES Must follow same rules to communicate
Name some ways of everyday communicating What do you need to communicate?
Network communication is similar Source/destination
Rules of how message is sent include: Message encoding; Message formatting and
encapsulation; Message size; Message timing; Message delivery options
MESSAGE ENCODING ENCODING
Converting info for travel on mediaEx: bits into electricity, light, radio waves
DECODING Interpret info from mediaEx: electricity, light, radio waves into bits
MESSAGE FORMATTING & ENCAPSULATION
FRAME
MESSAGE SIZE What if books where one long sentence?
Hard to understand.
When you speak, messages broken up in sentences Easier to process in smaller parts
Size of frames small Messages broken into small pieces Each segmented message is encapsulated &
sent Frames de-encapsulated, put back together &
read at destination
MESSAGE TIMING How fast or slow to talk
Access methodSpeak at same time= collisionWait turn to speak
Flow controlSpeak fast= confusionControl flow of data
Response timeoutNo response= repeat questionRules for how long to wait for response &
retransmit
DELIVERY OPTIONS
REVIEW Data is packaged up. What is this
process called?Encapsulation
The message and addressing info is encapsulated into a ___________.Frame
Converting bits for travel on an Ethernet cable is known as what? Also, what is it converted into?Encoding; electricity
REVIEW What kind of message goes to everyone?
Broadcast A room is filled with 25 computers. PC1
sends a message to PC4, 7, 10, 15, and 20. What kind of message has been sent? Multicast
Too much data is being sent too quickly between two communicating devices. If you don’t want dropped packets, what timing method would control how much is being sent at a time? Flow control
PROTOCOLS
3.2.1
COMMON PROTOCOLS Many protocols work together to send
data
PROTOCOL SUITES
3.2.2
PROTOCOL SUITE Set of protocols that work together
Standards developed to allow interoperability IEEE
Proprietary protocolsOne vendor controls how it operatesAppleTalk & Novell are examples
We’ll look at TCP/IP, an open standard
TCP/IP MODEL
DATA COMMUNICATION
STANDARDS ORGANIZATIONS
3.2.3
STANDARDS Open standards are good
ISOC- Internet Society IEEE- electrical standards
802.3 Ethernet802.11 Wireless
ISO- standards/ created OSI model EIA/TIA- electrical & telecommunications ICANN- IP addressing/domains
IANA- runs under ICANN
REVIEW Define a proprietary protocol.
Protocol that an organization controls What is the IEEE standard for Ethernet?
802.3 What is the IEEE standard for wireless?
802.11 You are requesting a web page…
What protocol is used 1st? HTTP
What protocol ensures delivery of it? TCP
What protocol helps find the best path? IP
What protocol formats it for transmission? Ethernet
REFERENCE MODELS
3.2.4
TCP/IP MODEL
TCP/IP MODEL
OSI MODEL
COMPARING THE MODELS
ACTIVITY
REVIEW What is layer 4 of the OSI model?
Transport What is layer 3 of the OSI model?
Network Which layer finds the best path?
Network Which layer is responsible for delivery of
the data?Transport
A piece of data at a layer is known as what?PDU
REVIEW What layer turns data into bits for
transmission on a cable, for example?Physical
Where are IP addresses?Network
HTTP is at which layer?Application
Where is data divided into segments?Transport
What is the PDU at layer 2?Frames
DATA ENCAPSULATION
3.3.1
ENCAPSULATION Data divided into smaller segments
Many conversations can be sent Multiplexing
Only parts of missing message can be resent
PDU
ENCAPSULATION
DE-ENCAPSULATION
ACTIVITY Complete the activity on 3.3.1.5
REVIEW In the TCP/IP model…
Data is sent from the Internet layer to the Network Access layer. False
Segments are sent from the Transport layer to the Internet layer. True
At which layer of the TCP/IP model would you find the logical address, or IP address? Internet layer
Name the OSI model from 7 to 1
ACCESSING LOCAL RESOURCES
3.3.2
ADDRESSING
LOCAL TRANSMISSION- ARP To find the MAC address of a device
within your network…ARP request sent as a broadcast
DOES NOT GO OUTSIDE A NETWORK Includes the IP of the destinationEvery NIC looks at it; only one with that IP
will respond with its MAC address
ACCESSING REMOTE RESOURCES
3.3.3
GET OUT OF THE NETWORK! If destination IP is outside of network, it
gets sent to the default gateway addressRouter port to get out of the network
PC 1192.168.1.110AA-AA-AA-AA-AA-AA
PC 2192.168.1.111BB-BB-BB-BB-BB-BB
FTP Server192.168.1.9CC-CC-CC-CC-CC-CC
R1192.168.1.111-11-11-11-11-11
R2172.16.1.9922-22-22-22-22-22
Web Server172.16.1.99AB-CD-EF-12-34-56
PROXY ARP You don’t know the destination MAC
ARP can’t be sent outside of the network The DG’s MAC address is substituted
REVIEW Which process finds out the MAC address of
a PC on the local network? ARP
At the Internet & Network layer, which address is logical? IP address
Which address is physical? What layer of the OSI? MAC; Data Link
When sending data outside your network, which address is used for the destination MAC? Default gateway MAC address
REVIEW & STUDY Complete the study guide handout
Take the quiz on netacad.com
Jeopardy review
SUMMARYIn this chapter, you learned: Devices must comply with
communication rules and protocols. TCP/IP is an example of a protocol suite.
Most protocols are created by a standards organization such as the IETF or IEEE.
The most widely-used networking models are the OSI and TCP/IP models.
SUMMARY Data that passes down the stack of the OSI model
is segmented into pieces and encapsulated with addresses and other labels.
The process is reversed as the pieces are de-encapsulated and passed up the protocol stack.
The OSI model describes the processes of encoding, formatting, segmenting, and encapsulating data for transmission over the network.
The TCP/IP protocol suite is an open standard protocol.
SUMMARY The names of layers in the OSI & TCP/IP
models.
Protocol Data Units (PDUs) are data, segment, packet, frame, and bits.
ARP & Proxy ARP are used in sending data.
Applying models allows individuals, companies, and trade associations to analyze current networks and plan the networks of the future.
NETWORK PROTOCOLS &
COMMUNICATIONS
Chapter 3
Intro to Routing & Switching