Specifications

Introduction
9
Network Addresses
The Network Number addresses the network. All stations on the same “network” will have the same Network
Number. Note that a network could be a single segment, or multiple segments joined by either bridges or repeaters.
In IPX internetworks, routers must be used to join different networks together.
Node Addresses
The Node Number identifies the individual stations in a Network. In IPX devices, this address is assigned
automatically and is identical to the MAC address. This means that the Node Number is self-configuring, and will be
unique within the Network because the MAC address that was copied is (supposed to be) unique.
The use of the MAC address as the Node Number allows IPX stations to be self-configuring. This makes the initial
configuration of a station much simpler, but there are drawbacks. The Node Numbers cannot be structured as
needed, with groups of stations having for example consecutive addresses. Instead, the network is forced to live with
whatever MAC address is assigned to the LAN port.
Socket Addresses
The Socket Number identifies the process within the source/destination that is communicating. Common Sockets
include File Servers (Socket Number 0451), SAP (Socket Number 0452), and RIP (Socket 0453). The Socket
Number can be thought of as the address of the upper layer using the IPX communication.
The Socket Numbers are assigned by Novell and do not change from LAN to LAN. In other words, all
communications with File Servers use Socket Number 0451. When a software vendor uses IPX to communicate
across a Netware network, the vendor will apply to Novell to receive a Socket Number for the application. As an
example, if Acme Schedule Company made a groupware scheduling program for Netware, they would get a Socket
assigned for their use. No other communications on the LAN would use the Acme Scheduler Socket.
Other IPX Header Information
The IPX header contains some other information besides the source and destination addresses.
Figure 1 - 4 IPX Header