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Communicating over the

Network

Network Fundamentals Chapter 2

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Objectives Describe the structure of a network, including the

devices and media that are necessary for successfulcommunications.

Explain the function of protocols in network

communications.

Explain the advantages of using a layered model todescribe network functionality.

Describe the role of each layer in two recognizednetwork models: The TCP/IP model and the OSImodel.

Describe the importance of addressing and namingschemes in network communications.

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Network Structure

The elements of communication

3 common elements of communication

Message source

The channel Message destination

The network

Data or information networks capable of carrying many differenttypes of communications

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Network Structure The elements of communication

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Network Structure How messages are communicated

Data is sent across a network in small chunks calledsegments

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Network Structure The components of a network

Network components

Hardware

Software

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Network Structure

Devices

End Devices: Computers, Servers, printers, IP-Phones,Mobile Devices, Security Cameras

Intermediary Devices:

Network Access Devices: Hubs, Switches, Wireless AccessPoints

Internetworking Devices: Routers

Communication Servers and Modems

Security Devices: Firewalls, Filtering Proxies

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Network Structure

End Devices and their Role in the Network

End devices form interface with human network &communications network

Role of end devices:

Client

Server

Both client and server

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Network Structure

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Network Structure Role of an intermediary device

Provides connectivity and ensures data flowsacross the network

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Network Structure Media

Network media this is the channel over which a messagetravels

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Network Types

Types of Media:

Metallic wires within cables

Glass or plastic fibers (fiber optic cables)

Wireless transmission

Criteria for choosing a network media:

The distance a signal can be transmitted within the medium

The environment where a media is to be installed

The amount of data and speed of transmission

The cost of media and installation

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Network Types

Local Area Networks (LANs)A network serving a home, building or campus is considered a

Local Area Network (LAN)

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Network Types

Local Area Networks (LANs) Characteristics

Span over a single Geographic Area

Services and Application are common for an organization

Administered by a single organization

No cost for transmission of data

Examples: Ethernet, Token Ring, FDDI, Wi-Fi

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Network Types

Wide Area Networks (WANs)

LANs separated by geographic distance are connected by anetwork known as a Wide Area Network (WAN)

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Network Types

Wide Area Networks (WANs) Characteristics

Span over a large Geographic Area

Use of a Telecommunication Service Provider (TSP)

Interconnects LANs

You pay for the Service

Examples: Leased lines, Frame Relays, DSL, ISDN, PSTN.

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Network Types

Definition of the Internet The internet is defined as a global mesh of interconnected

networks. An Internetwork that connects other networks.

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Network Types

Terminology

NIC Network Interface Card): Provides physical connection tothe PC or other host (end device)

Physical Port: A connection to the Networking Device (switch,

hub) where it connects to hosts or other networking devicethrough media

Interface: Ports on the Internetworking Device (Router) thatconnects to a Network.

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Network Types

Network Representations

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Function of Protocol in Network Communication

Network protocolsA protocol is a set of predetermined rules

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Function of Protocol in Network Communication

Network Protocols Network protocols are used to allow devices to communicate

successfully

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Function of Protocol in Network Communication

Terminology

Protocol Suite: collection of interrelated protocols (e.g.TCP/IP suite).

Protocol Stack: visualization method for protocols (e.g. OSImodel, TCP/IP Model).

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Function of Protocol in Network Communication

The protocols define:

The format or structure of the message

The method by which networking devices share information

about pathways with other networks

How and when error and system messages are passedbetween devices

The setup and termination of data transfer sessions

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Function of Protocol in Network Communication

Organisations developing protocols:

IEEE: Institude of Electrical and Electronic Engineers

IETF: Internet Engineering Task Force

ITU: International Telecommunication Union

EIA/TIA: Electronic/Telecommunication Industry Association

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Function of Protocol in Network Communication

Example of a Protocol Stack

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Function of Protocol in Network Communication Technology independent Protocols

Many diverse types of devices can communicate using thesame sets of protocols

This is because protocols specify network functionality, not theunderlying technology to support this functionality

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Layers with TCP/IP and OSI Model

The benefits of using a layered model Benefits include

Assists in protocol design

Fosters competition

Changes in one layer do not affect other layers

Provides a common language

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Layers with TCP/IP and OSI Model

Protocol and reference modelsA protocol model provides a model that closely matches the

structure of a particular protocol suite

A reference model provides a common reference for maintainingconsistency within all types of network protocols and services

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Layers with TCP/IP and OSI Model

The TCP/IP Model

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Layers with TCP/IP and OSI Model

The Communication Process

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The Communication Process

1. Creation of data at the Application layer of the originating sourceend device

2. Segmentation and encapsulation of data as it passes down theprotocol stack in the source end device

3. Generation of the data onto the media at the Network Accesslayer of the stack

4. Transportation of the data through the internetwork, whichconsists of media and any intermediary devices

5. Reception of the data at the Network Access layer of thedestination end device

6. Decapsulation and reassembly of the data as it passes up thestack in the destination device

7. Passing this data to the destination application at the Application

layer of the destination end device

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Layers with TCP/IP and OSI Model

Protocol data units (PDU) and encapsulation

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Protocol data units (PDU) and encapsulation Data - The general term for the PDU used at theApplication layer

Segment - Transport Layer PDU

Packet - Internetwork Layer PDU

Frame - Network Access Layer PDU

Bits - A PDU used when physically transmitting dataover the medium

Layers with TCP/IP and OSI Model

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Layers with TCP/IP and OSI Model

Sending and receiving messages Activity 2.4.6.1,2

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Layers with TCP/IP and OSI Model

The OSI Model

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Layers with TCP/IP and OSI Model

Comparison of the OSI and TCP/IP model

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Addressing and Naming Schemes

Encapsulation headers are used to managecommunication in data networks

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Addressing and Naming Schemes

Physical Addressing (Layer 2)

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Addressing and Naming Schemes

Logical Addressing (Layer 3)

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Addressing and Naming Schemes

Service Port Numbers (Layer 4)

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Warriors of the Net A network

Visualizationhttp://www.warriorsofthe.net

http://www.youtube.com/watch?v=LGnJw9rtjas

http://www.warriorsofthe.net/http://www.youtube.com/watch?v=LGnJw9rtjashttp://www.youtube.com/watch?v=LGnJw9rtjashttp://www.warriorsofthe.net/

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Homework

PT Lab 2.2.4.2Activity 2.2.5.1

Activity 2.4.4.1

PT Lab 2.4.8.2 PT Lab 2.6.1.2

Activity 2.6.2.1

PT Lab 2.6.1.2

Activity 2.7.1.2

PT Lab 2.7.1.3

Quiz 2.8.1.1

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Summary

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