6.6 Configuring EIGRP
6.6.3 Configuring EIGRP for IPX SAP updates
To reduce the frequency of SAP updates in a network that uses Cisco routers, perform the following steps:
  1. Enable EIGRP for IPX, as discussed earlier.
  2. Select the interface on which you want the SAP updates to be sent incrementally.
  3. Instruct the router to issue SAP updates only when a change occurs in the network, instead of the periodic update interval:

    router(config-if)#ipx sap-incremental eigrp autonomous-system-number [rsup-only]

LAN interfaces, such as Ethernet, Token Ring, and FDDI, have the rsup-only feature turned off by default. WAN links have the rsup-only feature turned on by default. When incremental updates are enabled on a LAN interface, another peer IPX EIGRP router should be present on that media. If an incremental update is enabled and no peer router is available, periodic SAP updates will not be sent. If a peer router becomes available, incremental updates will then be sent.