5-8 CHAPTER 5: ROUTING WITH IPX
The Elements of IPX Routing
IPX routers use the following elements to transmit packets over an
intranetwork:
■Router interfaces
■Routing tables
■SAP
Router Interfaces A router interface is the connection between the router and the network
number (address). In traditional routing models, the interface would be the
same as the port, since only one interface could exist per port.
In the LANplex system’s IPX routing, more than one port can be connected
to the network number. Therefore, the router interface is the relationship
between the ports and the network number (address) in your IPX network.
Each router interface has a network address. This address defines the
network number that the router interface is attached to. A router interface’s
IPX address serves two functions:
■It is used when sending IPX packets to or from the router itself.
■It defines the network number of the segment connected to that interface.
Routing Tables A routing table holds information about all the network segments. It allows
a router to send a packet toward its ultimate destination using the best
possible route. The routing information table contains an entry for every
network number that the router currently knows exists. A router uses the
routing information table when the destination network number of the
packet it is sending is not on a network to which it is directly connected.
The routing information table provides the immediate address of a
forwarding router that can forward the packet toward its destination.
The routing table consists of the following elements:
■Interface — Identifies the router’s interface that will be used to reach the
specific network segment.
■Address — Identifies the addresses for segments that the router currently
knows exists.