At 05:05 PM 1/7/02, Wilson, Christian wrote: >I know this is a dumb question, but do IPX routing protocols, such as >EIGRPand NLSP, use admin distances to prioritize between routing protocols?
It's not a dumb question. Administrative distance is a configurable Cisco feature on routers running multiple IP routing protocols. Although the concept and configuration could be applied to multiple IPX routing protocols, they don't seem to be. IPX networks are usually designed with IPX RIP/SAP on the edges and EIGRP or NLSP in the core. There's probably little need to run multiple routing protocols on anything other than the routers that connect the edges. Redistribution between RIP and EIGRP is enabled by default. Redistribution between NLSP and RIP is also enabled by default. (Redistribution between NLSP and EIGRP is disabled by default.) With that said, however, there's nothing stopping you from running RIP and EIGRP simultaneously on multiple routers and thus ending up with an EIGRP and RIP path to the same network. According to Ivan Pepelnjak in his "EIGRP Network Design Solutions" book, "IPX EIGRP routes are always preferred over IPX RIP routes unless they have a higher IPX hop count than the IPX RIP routes. In IP terms, you could say that IPX EIGRP has a lower administrative distance than IPX RIP)." I also found the following in the 11.0 documentation. I'm not sure if it's still true. "By default, the router redistributes IPX RIP routes into Enhanced IGRP, and vice versa. When routes are redistributed, a RIP route to a destination with a hop count of 1 is always preferred over an Enhanced IGRP route with a hop count of 1. This ensures that the router always believes a Novell IPX server over a Cisco router for internal IPX networks. The only exception to this rule is if both the RIP and Enhanced IGRP updates were received from the same router. In this case, and in the case of all other RIP metrics (2 through 15), the Enhanced IGRP route always is preferred over the RIP route when the hop counts are the same." Unfortunately, I couldn't find anything that confirms my suspicion that NLSP routes are preferred over both EIGRP and RIP. Cisco documentation just says this, which doesn't answer the question: "Once you enable Enhanced IGRP and NLSP redistribution, the router makes path decisions based on a predefined, nonconfigurable administrative distance." Priscilla >I can't find any admin distances on the documentation CD. Any help or a lnk >to the info would be greatly appreciated! ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=31225&t=31225 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
