nanog mailing list archives
Re: consistent policy != consistent announcements
From: John Scudder <jgs () ieng com>
Date: Thu, 13 Mar 1997 10:46:06 -0500 (EST)
Yep, policy filters run up against the policy of only announcing the single, best route. I've been thinking with policy filters and variable weighting, should it be changed to announcing the 'best' route that meets policy, even if it is the second or third 'best' route you know about.
Unless I misunderstand what you mean by "variable weighting", this would not be a good idea. It's a BGP design point for a router to only announce the route(s) that it is actively *using*. In your comment above, a. If a router has a route it believes is "best", why isn't it using it? b. Regardless of the answer, the router should announce the route it is using for its own forwarding. To do otherwise would be to lie about the path which traffic will take to the advertised destination. If policy forbids it from announcing the route it is using, so be it. (Or, if that's not acceptable change the policy.) By the way, this general fact about BGP (external announcements are governed by internal route selection) also means that for Randy to always announce the same route to his peer, he would have to change his own, internal routing policy to do cold-potato routing to one of the two candidate paths. This doesn't seem like a reasonable thing for a peer to demand he do. Regards, --John - - - - - - - - - - - - - - - - -
Current thread:
- consistent policy != consistent announcements Randy Bush (Mar 12)
- Re: consistent policy != consistent announcements John W. Stewart III (Mar 13)
- <Possible follow-ups>
- Re: consistent policy != consistent announcements Vadim Antonov (Mar 13)
- Re: consistent policy != consistent announcements Tony Barber (Mar 13)
- Re: consistent policy != consistent announcements Randy Bush (Mar 13)
- Re: consistent policy != consistent announcements Tony Li (Mar 16)
- Re: consistent policy != consistent announcements Sean Donelan (Mar 13)
- Re: consistent policy != consistent announcements Randy Bush (Mar 13)
- Re: consistent policy != consistent announcements John Scudder (Mar 13)
- Re: consistent policy != consistent announcements Vince Fuller (Mar 13)
- Re: consistent policy != consistent announcements Henry Kilmer (Mar 13)
- Re: consistent policy != consistent announcements David Schwartz (Mar 13)
- Re: consistent policy != consistent announcements the Riz (Mar 13)
- Re: consistent policy != consistent announcements Henry Kilmer (Mar 13)
- Re: consistent policy != consistent announcements Vince Fuller (Mar 13)
- Re: consistent policy != consistent announcements Henry Kilmer (Mar 13)
- Re: consistent policy != consistent announcements Vince Fuller (Mar 13)
- Re: consistent policy != consistent announcements David Schwartz (Mar 13)
- Re: consistent policy != consistent announcements Alan Barrett (Mar 13)
- Re: consistent policy != consistent announcements Randy Bush (Mar 14)
- Re: consistent policy != consistent announcements David Schwartz (Mar 13)