Autumn 2000John Kristoff1 Computer Networks Other Network Protocols.

Autumn 2000 John Kristoff 1

Computer Networks

Other Network Protocols


Motivation

Even though TCP/IP may have won the protocol wars, you will be able to

understand networking and even TCP/IP better if you learn about contrasting solutions and implementations. This

may help you to avoid reinventing the wheel or perhaps to borrow from the past's good ideas to solve seemingly

new problems.


Novell IPX/SPX

Novell proprietary Based on Xerox's XNS protocol system

Runs on top of Ethernet, Token Ring, etc. Usually used with NetWare OS's Very popular in corporate environments Declining usage


Novell Protocol Stack Illustrated


Internetwork Packet eXchange (IPX)

32-bit network, 48-bit node/host address Network is generally fixed at 32-bits Node address = IEEE 802 MAC

address Dynamic host address assigment Many features IP wishes it had!


IPX Routing

IPX Routing Information Protocol TTL counts up NLSP

Similar to OSPF and IS-IS Never took off

Concept of internal IPX numbers


Sequenced Packet eXchange (SPX)

Similar to TCP, but with no sliding window!

SPX II addressed the window size problem Though, not really well

Most Novell based apps avoided SPX It was inefficient and just got in the way Some newer apps used SPX II (e.g. Notes)


Service Advertisement Protocol (SAP)

Services are advertised periodically The anti-DNS system e.g. "I'm a Netware printer, here I am!"

Default interval was every 60 seconds Very chatty on large networks Does not scale

NDS was supposed to help


NetWare Core Protocol (NCP)

Novell's layer 5, 6 and 7 layers - kinda File access protocol Print services Login/authentication requests Messaging/management services Provided "burst mode" for file

read/writes


NetWare Directory Services (NDS)

Hierarchical database of network objects Based on X.500 and works with LDAP Logical and physical objects represented

Leafs, containers, users, drive mapping, etc. Naming structure similar to DNS

e.g. jdoe.networks.acme_us. Partitions and replicas stored on servers


AppleTalk

De Facto standard from Apple for Macs Very easy for end users Very chatty - scaling problems Runs on top of LocalTalk, Ethernet,

Token Ring, etc. TokenTalk and EtherTalk technologies

developed to support AppleTalk over IEEE LANs


This Picture is Wrong!


AppleTalk Network Layer Addressing

Only 3 bytes for network layer addresses! 2 bytes for network, 1 byte for host/node

Networks can be ranges e.g. 135-141 Arbitrary size, unlike IP (x2)

Looks/Requests network address Chooses host/node address at random!

Sends an AARP and looks for a reply


AppleTalk Routing

Routing Table Maintenance Protocol (RTMP) Similar to RIP

Seed Router 1 router configured with network, others

learn Nodes can optimize best exit router by

examining received packets Associates NET with ROUTER ADDRESS


AppleShare

Centralized file sharing system Runs on top of AppleTalk Also allows for

Printer sharing Peer to peer sharing Mail handling Security functions (ids and passwords)


ISO Network Layer

Connectionless Network Layer Protocol (CNLP)

Variable length, 20 bytes max Address specifies a host rather than

an interface Was considered to replace IPv4 Provided for autoconfiguration like

IPv6 and IPX


ISO Routing

Intermediate System to Intermediate System (IS-IS)

Link state routing protocol Very similar to OSPF Widely used by many ISPs Runs directly on top of a layer 2

protocol


ISO Transport Layer

Transport Protocol (TP) Four classes of transport layer protocols

TP0, TP1, TP2, TP3, TP4 Each provide increasing degree of features

TP4 is similar to TCP Three-way handshake Sliding window Retransmission timer


ISO Protocol Stack Illustrated


DECnet

Most commonly referred to as Phase IV Earlier phases and Phase V also defined

DECnet Phase V was CLNP or IP Only 2 bytes for addresses in Phase IV!

6 bits for network (area), 10 bits for host/node

Traditionally implemented on Digital Equipment Corp. machines (e.g. VAX) Ported to many other systems


DECnet Protocol Stack Illustrated


Systems Network Architecture (SNA)

Proprietary architecture from IBM There is no true layer 3 function in legacy

SNA - no routing! Historically built for token ring and source

routing (that was the layer 3 network) Central control (dumb terminals) APPN came later to provide distributed

control


SNA Protocol Stack Illustrated


SNA Components

Hosts (mainframe) Communications controller/FEP Cluster controllers - like a hub Terminals and printers Software (VTAM, NCP, emulation) Physical and logical concepts

(PUs/LUs)


Network Basic Input Output System (NetBIOS)

A simple API for LAN applications Assigns names for nodes on the network Very chatty - does not scale No network layer Often uses the NetBIOS Extended User

Interface (NetBEUI) Server Message Block (SMB) used to

provide file/print sharing (e.g. Samba)

Autumn 2000John Kristoff1 Computer Networks Other Network Protocols.

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