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Desert View IPX Documentation
Effects of IPX Traffic
Implementing Novell IPX will lead to an increase in traffic on the LAN and district WAN because IPX uses frequent broadcasts.
- Novell RIP – This is the routing protocol used on Novell networks. By default, routing table updates are sent every 60 seconds, adding to the IGRP updates which are also being broadcast every 90 seconds on the WAN link.
- Service Advertising Protocol – Network resources using IPX use Service Advertising Protocol (SAP) to advertise their network addresses and the services they provide. By default, SAP broadcasts are sent every 60 seconds. While routers do not forward SAP broadcasts, they do maintain SAP tables. When a client on one segment requests a service provided by a server on another segment, the router will respond to the request with the server's address. Since no administrative users will be running IPX, however, this will occur only on the WAN link. In addition, routers exchange SAP tables every 60 seconds. Since the design specifications require that IPX services be advertised across the district network to other curriculum LAN segments, this means that SAP table broadcasts will also be crossing the WAN link.
- Get Nearest Server Protocol – This is a type of SAP broadcast used by Novell clients at boot to find the nearest server for logon. There are 48 curriculum workstations running Novell, and which will therefore be sending GNS requests across the curriculum LAN segment each time they logon to the network.
Overall, we can expect a significant increase in traffic across the WAN core from Novell RIP and SAP table update broadcasts, as well as IPX traffic being exchanged between clients at different schools. Traffic from broadcasts on the LAN will be less noticeable due to the speed of the backbone, but there will still be an increase in traffic on the LAN from SAP broadcasts, GNS requests, and responses by the router to network service requests.
District IPX Network Number Addressing Scheme
Each network across the WAN must have a distinct network number. This applies to both IP and IPX addressing. We will therefore use the IP addressing scheme in choosing IPX network numbers by converting the IP network address to hex and using that as the IPX network address. On the Desert View network, the IP address of the curriculum network is 192.168.8.0. The IPX network address will therefore be C0A80800. The IP address of the T1 link to the Phoenix Data Center is 192.168.6.0. The IPX network address will therefore be C0A80600.
Router Configuration Changes
Along with TCP/IP, Novell IPX is the only other networking protocol that will be allowed to traverse the district WAN. Accordingly, we must enable the router to route IPX traffic. This includes choosing an encapsulation type on the ethernet interface. The most common encapsulation type for Novell NetWare after version 3.11 is Ethernet_802.2, called SAP by Cisco. Since the Novell server must be able to advertise services across the entire network, both the ethernet interface on the curriculum network and the serial interface connected to the WAN core must be configured with a Novell network address. Since no administrative workstations will be using IPX, it is not necessary to enable IPX routing on the second ethernet interface.
The commands needed to implement these changes are as follows:
Desert_View(config)# ipx routing
Desert_View(config)# interface ethernet 1
Desert_View(config-if)# ipx encapsulation sap
Desert_View(config-if)# ipx network C0A80800
Desert_View(config-if)# interface serial 0
Desert_View(config-if)# ipx network C0A80600