- TCP/IP and IPX Routing Tutorial
- IPX Routing
The following is a brief introduction to IPX routing in the context of a Novell environment. For more information, consult Novell’s IPX Router reference.
Because IPX is always dynamically routed, and the routing architecture works by “learning” network addressing automatically, there is usually no need to do anything special in the setup of an IPX network in order to get routing to function. Thus this section is provided for completeness only.
An IPX address consists of a 4-byte Network Number, a 6-byte Node Number, and a 2-byte Socket Number. The node number is usually the hardware address of the interface card, and must be unique inside the particular IPX network. The network number must be the same for all nodes on a particular physical network segment. Socket numbers correspond to the particular service being accessed. Consider the following IPX network:
Nodes A and D are Novell NetWare workstations, and Nodes B, C and E are Novell NetWare Servers. Node C has two Ethernet cards and acts as an IPX router between the two networks.
The NetWare Servers broadcast routing information and service advertisements to all nodes on the network segment using RIP/SAP or NLSP. Node C forwards this information to connected networks, so that workstations are made aware of the addresses of all file and print servers available, and servers are made aware of the routes to these other servers.
To address a service running on a server, each server has its own Internal Network Number, which is placed in the network number field of the IPX header.
For example, suppose A wants to access the file server E whose internal network number is 5E1C0155. A would have been made aware of E’s address through service advertisements broadcast by C. To learn how to reach E, it broadcasts a routing request. C receives this request and returns its own hardware node number. A therefore addresses an IPX packet to E using E’s internal network number of 5E1C0155 and node number 22-5A-4D-8C-C3-DA. The Ethernet header’s destination address is Node C’s node address of 34-56-78-9A-BC-DE. C then receives this IPX packet and observes that the IPX packet header’s destination address is not its own, so it transmits the packet on network DDEEAADD knowing that E is on that network, using an Ethernet header destination address of 22-5A-4D-8C-C3-DA.
See the WANPIPE® operations manual for information on configuring WANPIPE® for use with IPX.