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IPX Basics


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IPX Basics



IPX Addressing and Address Structure



Configuring IPX Addresses



IPX Routing Configuration



Configuring IPX Routing Protocols



Configuring IPX Filtering via Access Lists



Configuring Basic IPX Dialup Services



Verifying IPX Connectivity and Troubleshooting



Configuring IPX Type 20 Packet Forwarding







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Cisco Router Configuration

From: Cisco Router Configuration
Author: Bruce Pinsky; Allan Leinwand; Mark Culpepper
Publisher: Cisco Press (53)
More Information

6. IPX Basics

  • IPX Addressing and Address Structure

    Fundamentals of the address and network structure of the IPX protocol.

  • Configuring IPX Addresses

    Overview of the IPX addressing scheme plus address configuration examples for different LAN and WAN interface types.

  • IPX Routing Configuration

    Basics of IPX routing configuration using static routes and verifying IPX routing.

  • Configuring IPX Routing Protocols

    Characteristics of the IPX, RIP, and NLSP dynamic routing protocols and basic configuration examples.

  • Configuring IPX Filtering via Access Lists

    Controlling network access and security through the use of access-list and ipx access-group commands.

  • Configuring Basic IPX Dialup Services

    Setting up IPX client asynchronous dialup connectivity.

  • Verifying IPX Connectivity and Troubleshooting

    Identifying connectivity problems through the use of show,ping, and debug commands.

  • Configuring IPX Type 20 Packet Forwarding

    Options for configuring the IOS to forward IPX type 20 packets.

In the late 1970s, Xerox created a network protocol called Xerox Network Systems, or XNS, that was widely implemented by most major LAN vendors, including Novell, Inc. Novell made some changes to the protocol in the early 1980s, renamed it Internet Packet Exchange protocol (IPX), and incorporated it as part of NetWare. The NetWare transport layer protocol, the Streams Packet Exchange (SPX), was also derived from the XNS protocol suite.

NetWare is a suite of protocols for sharing resources—primarily print and file services—among workstations through a client-server implementation. Novell describes NetWare as a network operating system (NOS) because it gives end users access to resources that are available via the LAN or WAN. NetWare, a dominant corporate NOS, is widely deployed in many internetworks.

Figure 6-1 shows the multiple protocols commonly used in the NetWare protocol suite. We do not cover each of these protocols in this chapter but instead concentrate on explaining the protocols on the network and transport layers, namely IPX, IPX RIP (Routing Information Protocol), NLSP (NetWare Link State Protocol), SAP (Service Advertisement Protocol), and SPX. The other protocols shown in Figure 6-1 reference other internetwork technologies with which you may be familiar.

Figure 6-1. The IPX protocols suite.

IPX Addressing and Address Structure

IPX is a network layer protocol with its own proprietary addressing structure. This section introduces the IPX address structure that each IPX client (sometimes called a workstation by NetWare documentation) or server must have in order to communicate with other IPX devices on an internetwork.

An IPX address has two components, a 32-bit network component that applies to a given LAN or WAN segment and a 48-bit node component that uniquely identifies a client or a server. These two components, expressed together as network.node, are written using hexadecimal format. The two-layer hierarchy of the IPX address structure makes this addressing scheme scalable for internetworks, yet not as scalable as the multiple hierarchies of the IP addressing structure.

The network administrator assigns the network number for an IPX network segment in the same way that he/she selects IP subnets for given LAN and WAN segments. All IPX clients, IPX servers, and Cisco routers on the same LAN or WAN segment must have the same network number.

NetWare servers have internal IPX network numbers that are different than the IPX network numbers for any LAN or WAN interface. The internal IPX network number is used as the source network number for NetWare services on the server. We'll discuss service advertisement later in this chapter when we discuss SAP. A Cisco router can be configured with an internal IPX network number using the global configuration command ipx internal-network. We discuss this internal network number further in the section on NLSP.

Each IPX server or client needs to have a unique node number on a LAN or WAN segment. Typically, IPX clients derive this unique number by reading the 48-bit data link address on their LAN interface and then using that number as their unique network layer node address. Although the LAN interface data link address is the same as the IPX node address, do not conclude that a client uses these two addresses in the same manner. The data link layer address is used for data link layer encapsulation, such as ethernet or Token Ring. The IPX node address is the second portion of the IPX network layer network.node address for a given client.

Using the data link layer address to determine a unique 48-bit IPX node address is not required by the IPX protocol. You can have a node address that does not match a data link layer address as long as the node address is unique on a given IPX network. For example, we have seen that an IOS device can have multiple LAN interfaces. When IPX routing is enabled, the IOS device chooses the data link layer address on the first LAN interface in the device as the unique node address for all IPX network segments. Now imagine that the data link layer address on Ethernet 0 of a router is 0000.0c11.12ab. If Ethernet 0 is the first LAN interface in this router and if the router is connected to IPX network 10 and IPX network 20, the router is seen as 10.0000.0c11.12ab on IPX network 10 and 20.0000.0c11.12ab on IPX network 20.

The IOS global configuration command ipx routing enables IPX routing in an IOS device. The device automatically chooses an IPX node number based on the first LAN interface when this global configuration command is configured. In the following example, we enable IPX routing on the SF-2 router on the ZIP network:

Configuring from terminal, memory, or network [terminal]?
Enter configuration commands, one per line.  End with CNTL/Z.
SF-2(config)#ipx routing


If your router does not have a LAN interface, you must configure a unique IPX node address as an optional parameter to the ipx routing command.

The use of the data link layer address to determine the IPX node address simplifies the job of the network administrator because IPX clients do not need manual configuration. Also, this mapping of data link layer address to network layer address can eliminate the need for a separate protocol to map between the addresses on these two layers, such as ARP, which is discussed in Chapter 4, “TCP/IP Basics.”


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