© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1Version 4.0

Communicating over the Network

Network Fundamentals – Chapter 2

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What will we Learn from chapter 2? Describe the structure of a network

Explain the function of protocols.

Explain the advantages of using a layered model .

Describe the role of each layer In the:TCP/IP model OSI model.

Describe the importance of addressing and naming schemes.

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Network Structure Elements of communication

• Message source• The channel• Message destination

– Networks carrying different types of messages:– Data, voice, video, images

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Network Structure How messages are transmitted

– Messages are sent across a network in small “chunks” called segments, packets, frames, cells…

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Network StructureComponents of a network

• Hardware• Software

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Network Structure End Devices

– Interface with humans or other devices– Role of end devices:

• Client• Server• Printers, routers…• Any terminating networking device

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Network StructureIntermediary devices in contrasted to the role of end

devices• Provides connectivity and ensures data flows

through the and across network

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Network Structure What is network media?

The path or channel over which a message travels

What are the criteria for making media choice?

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Network TypesLocal Area Network (LAN)

– A network serving a home, building or campus may be considered a Local Area Network (LAN)

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Network TypesWide Area Networks (WANs)

– Specialize networks connecting LANs, MANs, PANs…

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Network Types What is the Internet

– A global mesh of interconnected networks (WANs, MANs, LANs, PANs…

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Network Types Symbols used to represent network devices and media

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Function of Protocol in Network Communication Protocol

– A set of rules

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Function of Protocol in Network CommunicationNetwork protocols are used to govern communicate between

devices

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Function of Protocol in Network CommunicationIndustry standards

– A process or protocols that has been endorsed by the networking industry and ratified by a standards organization

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Function of Protocol in Network Communication Technology independent Protocols

– Diverse types of devices can interact using standard sets of protocols

– Network protocols specify network functionality, not the underlying device technology

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Layers within the OSI and TCP/IP Reference Models

The benefits of a layered model• Aids in protocol design• Provides for corporate competition• Changes in one layer do not affect other layers• Provides for standard interfaces between devices

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Layers with TCP/IP and OSI Model

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Layers with TCP/IP and OSI ModelThe Communication Process

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Layers with TCP/IP and OSI ModelProtocol Data Units (PDU) and encapsulation

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Layers with TCP/IP and OSI ModelProcess of sending and receiving messages

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Layers with TCP/IP and OSI Model– A protocol model provides a model that closely matches the

structure of a particular protocol suite– A reference model provides a common reference for

maintaining consistency within all types of network protocols and services

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Layers with TCP/IP and OSI ModelOSI Reference Model

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Layers with TCP/IP and OSI ModelOSI and TCP/IP model

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Addressing and Naming SchemesHow labels in encapsulation headers are used to manage

communication in data networks

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Addressing and Naming Schemes Ethernet MAC Addresses, IP Addresses, and TCP/UDP

Port numbers

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Addressing and Naming SchemesHow labels in encapsulation headers are used to manage

communication

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Addressing and Naming SchemesHow information in the encapsulated header is used to identify

the source and destination processes for communication

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What did I Learn from Chapter 2 Describe the structure of a network

Explain the function of protocols.

Explain the advantages of using a layered model .

Describe the role of each layer In the:TCP/IP model OSI model.

Describe the importance of addressing and naming schemes.

30© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Communicating over the Network

NextApplication Layer Functionality and Protocols