nanog mailing list archives
RE: AS_PATH length and route selection (WAS: Strange BGP announcement)
From: "Martin, Christian" <CMartin () mercury balink com>
Date: Tue, 17 Nov 1998 22:29:01 -0500
So, would anyone care to discuss (from an operational POV) what removing AS_PATH length from the BGP route selection algorithm will do to the Internet?
You determine your local policy based on the tools that you have. If AS_PATH length were not in the algorithm by default, you could force it in there (in Cisco IOS) using route maps and regexps. For example: ! route-map MATCH_LONGER_THAN_5_ASPATH_HOPS permit 10 match as path 5 set local-preference 50 ! route-map DISCARD_LONGER_THAN_5ASPATH_HOPS permit set local-preference 100 ! ip as-path access-list 5 permit ^[0-9]+\ [0-9]+\ [0-9]+\ [0-9]+\ [0-9]+_ ! This goes for any routing protocol, not just BGP. -Chris
Current thread:
- RE: AS_PATH length and route selection (WAS: Strange BGP announcement) Martin, Christian (Nov 17)