From: Joe Chang (changjoe@earthlink.net)
Date: Mon Mar 03 2003 - 15:58:15 GMT-3
I understand how the command:
neighbor ip-address advertise-map map1 non-exist-map map2
works, but can't quite grasp when it would be useful. Excepted out of the BGP
configuration guide on the CD:
"Can be used in a multihomed network, in which some prefixes are to be
advertised to one of the providers, only if information from the other
provider is missing. This condition would indicate a failure in the peering
session, or partial reachability.
If the same information is advertised to all providers in a multihomed
environment, the information is duplicated in the global BGP table. When the
BGP Conditional Advertisement feature is used, only partial routes are
advertised to each provider, and the size of the global BGP table is not
increased with redundant information. The administrator can also guarantee the
path that inbound traffic will follow because only specific paths are
advertised to providers."
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_
c/ipcprt2/1024384
Why would you advertise a route to one provider only if the other provider is
no longer advertising another set of routes?
How does that have to do with managing redundant routes?
This archive was generated by hypermail 2.1.4 : Sat Apr 05 2003 - 08:51:31 GMT-3