nanog mailing list archives
AS_PATH length and route selection (WAS: Strange BGP announcement)
From: I Am Not An Isp <patrick () ianai net>
Date: Tue, 17 Nov 1998 17:46:50 -0800
At 05:09 PM 11/17/98 -0800, Tony Li wrote:
patrick () ianai net (I Am Not An Isp) writes:You said you wanted routers that followed the RFC. The RFC does not mention list AS_PATH length as a route selection criteria. I have been told that the draft for the next rev specifically prohibits using AS_PATH length as a route selection criteria.Patently false. In particular, the spec allows an implementation to invoke local policy when computing the local preference of a route. An implementation can reasonably incorporate the AS path length in its local preference calculations as part of its policy.
Guess that answers the question. So the draft for the next version of BGP does not list as-path length as a necessary criteria, but does leave the door open for vendor implementations (much like the current standard). This, of course, leads to many, many other questions (such as the possibility routing loops caused by different local policies as was seen with implementations of BGP4), but few of which are of a truly operational issue. So I will apologize for starting a thread based on mis-information and go back to my cave.
Tony
TTFN, patrick I Am Not An Isp www.ianai.net "Think of it as evolution in action." - Niven & Pournelle
Current thread:
- Re: Strange BGP announcement Enke Chen (Nov 10)
- RE: Strange BGP announcement Winfried Haug (Nov 13)
- Re: Strange BGP announcement Enke Chen (Nov 13)
- Re: Strange BGP announcement Andrew Bangs (Nov 13)
- Re: Strange BGP announcement I Am Not An Isp (Nov 16)
- Re: Strange BGP announcement Andrew Bangs (Nov 17)
- Re: Strange BGP announcement I Am Not An Isp (Nov 17)
- Re: Strange BGP announcement Tony Li (Nov 17)
- AS_PATH length and route selection (WAS: Strange BGP announcement) I Am Not An Isp (Nov 17)
- Re: AS_PATH length and route selection (WAS: Strange BGP announcement) Tony Li (Nov 17)
- Re: AS_PATH length and route selection (WAS: Strange BGP announcement) Ben Black (Nov 18)
- Re: Strange BGP announcement Enke Chen (Nov 13)
- RE: Strange BGP announcement Winfried Haug (Nov 13)
- Re: Strange BGP announcement Vijay Gill (Nov 17)
- Message not available
- AS_PATH length and route selection (WAS: Strange BGP announcement) I Am Not An Isp (Nov 17)
- Re: AS_PATH length and route selection (WAS: Strange BGP announcement) Vijay Gill (Nov 17)
- Re: AS_PATH length and route selection (WAS: Strange BGP announcement) Sean M. Doran (Nov 20)
- <Possible follow-ups>
- RE: Strange BGP announcement Martin, Christian (Nov 17)