© agilent technologies copyright 2000 h7211a+212, rev. 2.0 review of wan protocol basics

© Agilent TechnologiesCopyright 2000H7211A+212, Rev. 2.0

Review of WAN Protocol Basics

Review of WAN Protocol Basics


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Lesson 1 - AgendaLesson 1 - Agenda

Data Communications FundamentalsIntroduction to Network ProtocolsPhysical InterfacesBit Oriented ProtocolsBasic Analysis with the Internet

Advisor


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Lesson 1 - ObjectivesLesson 1 - Objectives

On Completion of this lesson you will be able to: List and explain data communications fundamentals as they apply to

wide area networks. Define the term network protocol. Explain the OSI seven-layer protocol model, peer-to-peer

communications and protocol encapsulation. Explain bit oriented protocol and give examples. Identify and describe the different interfaces and components of the

Internet Advisor. Demonstrate how to connect the Internet Advisor to a network under

test.


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Data Communications Fundamentals

Data Communications Fundamentals

Communications ModesDTE/DCE TerminologyWide Area Analog/Digital TransmissionMultiplexing Private Leased LinesPublic Switched Data Networks


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Communication ModeCommunication Mode

Full Duplex Half Duplex

Simplex

one direction always

both directions always

alternate one direction

and then the other


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DTE/DCE TerminologyDTE/DCE Terminology

Customer Premise

Wide Area Network

Full Duplex

Line (DCE)

EQPT (DTE)

Data TerminalEquipment (DTE)

Data Circuit-TerminatingEquipment (DCE)


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Wide Area Analog/Digital Transmission

Wide Area Analog/Digital Transmission

modem modem

analog transmissiontypically asynchronoustypically low speed (<=56kbps)

digital transmissiontypically synchronoustypically high speed (>=56kbps)

DSU/CSU DSU/CSU


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MultiplexingMultiplexing

Transmission of more than one signal on a single communications line

Increases the number of communications sessions that can be maintained at one time

Various types – Time Division Multiplexing – Frequency Division Multiplexing


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Time Division MultiplexingTime Division Multiplexing

A B B A C AB

AB

C

D


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Private Leased LinesPrivate Leased Lines

Point to Multipoint

Point to Point

Fully Meshed


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Public Switched Data Networks

Public Switched Data Networks

X.25Frame RelayATMSMDSISDN


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Summary of Data Communications Fundamentals

Summary of Data Communications Fundamentals

Binary communicationsMost often serial in networksFull duplex communications occurs in both directionsDTE on customer site while DCE on WANMultiplexing allows more than one communications

channel on the same line Time division multiplexing WAN cover large distances


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Introduction to Network Protocols

Introduction to Network Protocols

Definition Protocol Functions ISO Reference Model Peer to Peer Communications Data Encapsulation from Higher

Layers


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Definition of Communications Protocol

Definition of Communications Protocol

Set of communications rulesDefines addressingDefines syntax and semanticsAllows communications between disparate systems

– Communication rules – Connection control


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One Adam 12, HQ.

What’s your 10-22?

Over.

HQ, One Adam 12.

I’m going 10-22 at

DD for a cuppa java.

Over.

Radio Communications Protocol

Radio Communications Protocol


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ISO Reference ModelISO Reference Model

Physical

Application

Presentation

Session

Transport

Network

Data Link

Responsible for the transmission of bits. Includes themechanical, electrical and functional physical interface.

Responsible for ensuring error-free, reliable flow of dataacrossa physical link.

Responsible for end-to-end connectivity through the network. Includes routing and flow control.

Responsible for moving data between nodes; providingreliable or unreliable data transfer. Includes packetfragmentation, error detection, and retransmission.

Responsible for establishing, maintaining and terminatinglogical connections.

Responsible for format and code conversion. Includesformatting the syntax of data.

Provides access to the network for the end user orsoftware application.


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AddressingConnection controlOrdered delivery and

sequencingFlow controlError control

Protocol FunctionsProtocol Functions

Segmentation and reassembly

Encapsulation (control plus data)

Multiplexing

– Message– Other protocols


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Peer-to-Peer Communications

Peer-to-Peer Communications

Physical

Application

Presentation

Session

Transport

Network

Data Link

Application

Presentation

Session

Transport

Physical

Network

Data Link

Physical

Network

Data Link


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Each Protocol Layer Encapsulates Data from the

Layer Above

Each Protocol Layer Encapsulates Data from the

Layer Above

L7 -- Application

L5 -- Session

L4 -- Transport

L3 -- Network

L2 -- Data Link

L1 -- Physical

User or user program

Bit Stream

User Data

Data

Data

Data

Data

Data

FCSDLH

AH

PH

SH

TH

NH

Flag Flag

L6 -- Presentation


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Protocol Layers and Stacks

Protocol Layers and Stacks

WAN protocol analysis focuses on the lower three layers

– Physical, Data Link and NetworkDifferent protocol stacks often share the same

lower three layers– For example, IP, IPX and SNA over Frame

Relay


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Protocol SummaryProtocol Summary

Protocols are sets of rules that allow computer with different characteristics to communicate with one another

Protocol stacks share common lower layers for actual communication

Peer-to-Peer communication occurs between upper layers

Lowest three layers often involved in network analysis and troubleshooting


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Physical InterfacesPhysical Interfaces

Physical interfaces are hardware components that attach to the physical media that transmit and receive network signals

Physical interfaces are associated with one or more protocols that utilize the interface to perform the function of the lower layers of the ISO reference model

Physical interface standards are sets of common features that manufacturers use to produce products that operate with one another


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Typical WAN Physical Interfaces

Typical WAN Physical Interfaces

RS-232/V.24V.35RS-449/V.36 T1E1ISDN Basic Rate Interface (BRI)ISDN Primary Rate Interface (PRI)


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Introduction to Bit-Oriented ProtocolsIntroduction to Bit-Oriented Protocols

Definition Data Communications Today: Bit-Oriented

Protocols Examples of Bit-Oriented Protocols The Control Field Specifies the Frame Type Point-to-Point Protocol Bit-Oriented Protocols Summary


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Data Communications Today:

Bit-Oriented Protocols

Data Communications Today:

Bit-Oriented Protocols

01 E3 FCSThe quick brown fox...

DataControl FlagAddressFlag FCS


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Examples of Bit-Oriented Protocols

Examples of Bit-Oriented Protocols

SDLC (Synchronous Data Link Control) HDLC (High-level Data Link Control) LAP-B (Link Access Procedure-Balanced) ADCCP (Advanced Data Communications Control Procedures) And many others

01111110 01111110

8 bits 8 or 16 bits 8 or 16 bits optional (multiple of 8 bits) 16 bits 8 bits

payload (next protocol)

frame type identification, frame numbering

link level addressing

DataControl FlagAddressFlag FCS

Framedelineation


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Point-to-Point Protocol (PPP)

Point-to-Point Protocol (PPP)

Synchronous PPP Asynchronous PPP Multilink PPP

InformationControl FlagAddressFlag FCS01111110 01111110

8 bits 8 bits 8 bits 16 bits optional (multiple of 8 bits) 16 bits 8 bits

next protocol type field

03 hex identifies PPP information frame

not used (FF hex)

11111111 00000011

Type Field

payload (next protocol)

Synchronous PPP frame format:


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Bit-Oriented Protocol Summary

Bit-Oriented Protocol Summary

Bit oriented protocols can transmit more types of data than can character oriented protocols

Fields within the protocols (not control characters) manage network overhead and physical layer maintenance


Connecting the Agilent Technologies Internet Advisor

to the Network Under Test



modemmodem

Asynchronous

RS-232C/V.24(RS-449/V.36 or V.35)

RS-232C/V.24(RS-449/V.36 or V.35)






Synchronous

DSU/CSU DSU/CSU

T1 DSXCEPT - E1RS-232C/V.24RS-449/V.36X.21or V.35

T1 network, CEPT - E1 or DDS 4-wire

R R


Interface ConfigurationInterface Configuration

DTE clock source: DTE or DCE (default) Data sense: normal, inverted, NRZI-external

RS-232C/V.24RS-449/V.36V.35

V-series interfaces include:

Bits/secondor

Interface configuration:


Agilent Technologies Internet Advisor

Configuration Menu

Agilent Technologies Internet Advisor

Configuration Menu

Interface/Protocols– Data source– Monitor options– Protocols

Decode TableFilters/CountersLog

– Disk logging options– Disk logging configuration


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Lesson 1 - ReviewLesson 1 - Review

You should be able to: List and explain data communications fundamentals as they apply

to wide area networks. Define the term network protocol. Explain the OSI seven-layer protocol model, peer-to-peer

communications and protocol encapsulation. Explain bit oriented protocol and give examples. Identify and describe the different interfaces and components of

the Internet Advisor. Demonstrate how to connect the Internet Advisor to a network

under test.

© agilent technologies copyright 2000 h7211a+212, rev. 2.0 review of wan protocol basics

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