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IPX/SPX• Novell Internetwork Packet Exchange

(IPX) has been around since 1980’s. • Novell Netware was the most popular

network operating system in 1980’s.• Currently, Novell uses TCP/IP as

default network protocol. • Why should we learn about IPX/SPX?

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IPX/SPX Protocol Stack

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IPX/SPX Protocol Stack• Internetwork Packet Exchange (IPX)

– Connectionless, predominantly layer 3 protocol– Responsible for finding the best path through a

multipath IPX network• Sequenced Packet Exchange (SPX)

– Connection-oriented layer 4 protocol– Provides guaranteed delivery services for the

connectionless IPX• Service Advertisement Protocol (SAP)

– Operates at layers 5, 6, and 7– Advertises services running on IPX/SPX servers

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IPX/SPX Protocol Stack• NetWare Core Protocol (NCP)

– Functions at layers 4, 5, 6, and 7 of the OSI model

– Facilitates client/server interaction on a NetWare network

• Routing Information Protocol (RIP)– Distance-vector protocol built into the IPX/SPX

protocol stack– Operates at layer 3– Uses ticks and hop counts as metrics

• NetWare Link Services Protocol (NLSP)– Link state routing protocol designed by Novell– Functions at layer 3

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IPX/SPX Addressing• 80-bit (10 bytes) addresses consisting

of a 32-bit (4 bytes) network portion and a 48-bit node portion– The network administrator arbitrarily

assigns the network portion– No subnetting! No address classes! – MAC address of the node makes up the

node portion of the address• Addresses normally appear in hexadecimal

format• 0000.7C80.0000.8609.33e9

– What is good about using MAC addresses?

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Communication• Client-Server

– Novell Netware follows a strict client-server model.

– Every Netware server builds a service advertisement table comprising all the network resources that it is aware of.

– Clients use Get Nearest Server (GNS) request to locate servers.

• Server-Server– Servers use SAP and RIP.

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Service Advertisement Protocol (SAP)• SAP advertisements on an

IPX/SPX network allow servers to “advertise” running services to network clients

• NetWare servers take SAP broadcasts and build SAP tables.

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Encapsulation

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Lab