Cabletron Systems CSX1200, CSX1000 manual IPX Routing Protocol Background Information, Sap

CONFIGURING IPX

IPX Routing Protocols

RIP/SAP NUMBER OF TABLE ENTRIES

Specifies the maximum number of routing entries which can be stored in the route or service table. You may select a number between 20 and 3072. The default value is 141

IPX ROUTING PROTOCOL BACKGROUND INFORMATION

Routing Information Protocol (RIP) and Service Advertising Protocol (SAP) are used to automate the exchange of information across a network. These discovery protocols reduce the need to manually update routing and service tables.

IPX RIP is a protocol used to exchange routing information among IPX devices. RIP maintains a routing table of routing information gathered across the network. RIP broadcasts this information (either periodically or triggered by events) to update other routers. RIP determines the fastest path between two points on a network in terms of the number of “ticks” between those points.

IPX SAP is a protocol used to exchange service information among IPX devices. Servers use SAP packets to advertise their particular services. Routers retrieve these packets and store them in tables. Like RIP, routers then broadcast this service information to update other routers.

ROUTING/SERVICE TABLES

The system stores IPX routing information in a table. Each time a packet is received, the routing table is referenced to determine to which network interface to forward the packet. There are three types of routes stored in this table:

•static

•RIP (learned)

•internal

Static routes are configured locally on the system. These routes are stored, used internally and advertised to other routers using RIP.

RIP routes are learned from incoming RIP packets. These routes are stored, used internally and advertised to other routers using RIP.

Internal routes are stored and used by the system exclusively. These include routes for:

•the internal network number of this router

•the broadcast address for each IPX network interface configured

•the individual address for each IPX network interface configured

The maximum number of routes to be stored depends on the size and topology of the IPX network. Routers in the same network may have large differences in the maximum number of routes they store just because of their location in the network. Because of these factors, and limited memory in the router, the maximum number of routes for each router must be configurable.

Similarly, the system also stores IPX service information in a table. Each time service information is requested, the service table is referenced to determine the IPX address of the server. The following service entries are stored in this table:

•static

•SAP

Workgroup Remote Access Switch 279