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