Help about Routing loops?

[imran_mcse]

I have found that there are some methods like split horizon, hold down timers, triggered updates, rout poison used in distance routing protocols for avoiding routing loops. Which one is best from all of this , and what is being used by default in RIP and IGRP. Is there any command with which we can customize default behavior and use our liking method from one of above. Pls help.

[smif101]

I think your best bet is to run OSPF or EIGRP and design your network in a hierarchical manner.

Jason Smith

[imran_mcse]

Thanx for ur kind reply Jason Smith.

Dear i want this information only for the sake of knowledge not for practial implementations. so pls give me detail for my above problem just for knowledge.

[vcjones]

None of them are "best" as each can fail under the "right" conditions. See the RIP RFC for a discussion of the implementation of a distance vector routing algorithm and its weaknesses (http://www.ietf.org/rfc/rfc1058.txt). For more technical details and richer explanations, head for your nearest technical library and read the sections of Perlman or Tannenbaum on routing.

As for what is being used by default, the defaults are not standardized for RIP and vary by vendor. For the IGRP defaults, the answer can be found by searching www.cisco.com :-) and is left as an exercise for the reader...

As for what is configurable, that too is documented on www.cisco.com. Try reading the command reference for IP routing, they are a reasonable length if you go back to circa IOS 10.3, which about when IGRP peaked before being obsoleted by EIGRP.

Good luck and have fun!

Vincent C Jones

www.networkingunlimited.com