LAN Protocols

Chapter 5

Learning ObjectivesExplain the following LAN protocols and how they work with network operating systems: IPX/SPX, NetBEUI, AppleTalk, TCP/IP, SNA, DLC, DNA

Discuss and implement techniques to improve LAN performance

How LAN Protocols Work with Network Operating SystemsGive meaning to simple electrical signal that are carried on network communications cables

Can be transported individually or in combinations of two, three, or more

Multiple LAN ProtocolsAdvantage

Network can perform many different functions on same LAN

DisadvantageSome protocols operate in broadcast mode, causing a significant amount of redundant network traffic

Properties of a LAN ProtocolReliable network links

Relatively high speeds

Source and destination node address handling

Adherence to network standards (particularly IEEE 802)

LAN Protocols and Network Operating Systems

IPX/SPX and Novell NetWareIPX (Internetwork Packet Exchange)

Use with NetWare file server operating system

Routable, but chatty

SPX (Sequenced Packet Exchange)Enables exchange of application-specific data with greater reliability than IPX

Often used for exchange of database data

Deployment of IPX/SPXDOS-based computers

DOS shell drivers created by NetWare

Windows-based computersNovell Client32

Open Datalink Interface (ODI)

Network Driver Interface Specification (NDIS)

Microsoft’s NetWare Link (NWLink)

NDIS Network Architecture

IPX/SPX and Novell NetWareEmulation of IPX/SPX

Binding via NDIS

Other Protocols Used with NetWare

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Other Protocols Used with NetWare

NetBEUI and Microsoft Windows Servers

NetBEUI (NetBIOS Extended User Interface)

Developed by IBM in mid-1980sIncorporates NetBIOS for communications across a networkNative protocol for Windows NT ServerNot routable; most suited for small LANs using older Microsoft or IBM operating systemsCorresponds with several layers of OSI model

Why NetBEUI Works Well on Microsoft Networks

Simple to install

Handles large number of communication sessions on one network

Low memory requirements; can be quickly transported over small networks

Solid error detection and recovery

Disadvantages of NetBEUIInability to route medium-sized and large networks; not enough information in NetBEUI frame to identify specific networks

Few network analysis tools

AppleTalk and Mac OSAppleTalk

Peer-to-peer protocol used on networks for communications between Macintosh computers

Connectivity supported by Windows NT, Windows 2000, Windows .NET, and NetWare Server

AppleTalk Peer-to-Peer Networking

Comparison of AppleTalk Phase I and Phase II

Phase 1 Phase IINo internetworking; allows only one zone

Permits internetworking; up to 255 zones

Maximum number of stations: 254

Maximum number of stations: several million

Addressing accomplished by providing a node ID

Addressing uses combination of node ID and network identification

Functions only on a network in which it is the sole protocol

Can work on a network that uses multiple protocols

Services of AppleTalkRemote access to network files via AppleShare File Server Application

Printing services through AppleShare Print Server application

File services to DOS- and Windows-based systems via AppleShare PC application

Protocols Associated with AppleTalk

AARP

ADSP

AFP

ASP

ATP

DDP

ELAP

LLAP

NBP

PAP

RTMP

TLAP

ZIP

TCP/IP and Multiple Server Systems

TCP/IP (Transmission Control Protocol/ Internet Protocol)

Most widely used protocol

Offers a suite of protocols

Protocol of the Internet

Supported by most network server and workstation operating systems

Advantages of TCP/IPInternational language of network communicationsDesigned for use with wide range of network devicesMain protocol of most computer operating systemsMany troubleshooting and network analysis toolsUnderstood by a large body of network professionals

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Protocols and Applications of the TCP/IP Suite

SNA and IBM Operating Systems

SNA (Systems Network Architecture)Layered communications protocol used by IBM for communications between IBM mainframes and devices

Uses token ring as the access method

Advantages and Disadvantages of SNA

AdvantagesAvailable for over 25 years

Provide reliable and tested communications with IBM systems

DisadvantageProprietary; requires special devices and complex training to configure, manage, and troubleshoot

Physical Units on an SNA Network

Protocols and Applications That Work Through SNA

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DLC for Accessing IBM Operating Systems

DLC (Data Link Control) protocolEmulates SNA on Microsoft Windows operating systems

Not routable

Not truly designed for peer-to-peer communications between workstations, but only for connectivity to older IBM mainframe

DNA for Digital (Compaq) Computer Operating Systems

DNA (Digital Network Architecture)Developed for use on networks using DEC computers

AdvantageClosely follows OSI Reference model

DisadvantagesProprietary implementation

No longer widely used

Improving LAN PerformanceMinimize number of LAN protocols that must cross each router

Decreases the work routers must perform

Enables routers to process traffic faster

Does not create unnecessary traffic on network

Which Protocol?Do packets need to be routed?Size of network?Types of servers in use and the protocols they use?Are there mainframe host computers; what protocols do they use?Direct access to Internet or Web-based intranet applications?Speeds needed for WAN connections?Mission-critical applications?

Improving LAN PerformanceConnectivity issues

Eliminate unnecessary protocols configured on workstations

Chapter SummaryCommonly used LAN protocols and the network operating systems with which they are usedAdvantages and disadvantages of LAN protocolsImproving LAN performance by using only the protocols necessary in a particular situation