At 06:03 PM 11/17/98 -0500, Vijay Gill wrote:
You appear to have misunderstood the problem. The issue has nothing to do with route selection, or are you talking about FastPath(TM, Pat Pending) here?
Cute, Vijay. Really cute. Of course, if everyone had only licenced it, we wouldn't have this problem now, would we? :p
The issue is that an invalid as-path attribute was injected from somewhere. The cisco as-path sanity check code failed to pick it up.
[SNIP] I have not misunderstood the problem, you have misunderstood my response. Someone posted that the routers should follow the RFC. I was commenting that you should be careful what you wish for. If we magically made all routers strictly conform to the RFC instantly, it would have solved this particular problem, but it would have caused *much* larger problems for the 'Net at large. I was also hoping to start a debate by those more knowledgeable than I about the ... wisdom of intentionally removing what is currently far and away the most used metric for route selection from the next version of BGP; namely: AS_PATH length. (At least I was under the impression that AS_PATH length was the used more than all other metrics combined for route selection in the backbone.) RFC1771 does not list AS_PATH length as a selection criteria - but at least RFC1771 does not specifically forbid use of AS_PATH length, as the draft for the next version does. Or perhaps I'm just misinformed. I have not actually read the draft for BGP 4+ (or whatever they're calling it now). This is second hand information, but I consider it to be from a very reliable source (even if he doesn't like ciscos ;). I am also not saying removal of this metric is a gigantic mistake, but my thought process to date leads me to tentatively believe it would be ... suboptimal. However, the people writing the spec obviously know more about it than I do, perhaps I've overlooked something. 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?
/vijay
TTFN, patrick P.S. Before anyone goes off on me, I once again *agree* that the least cisco could do is deal with malformed announcements and the errors they generate properly. There are just other parts of the RFC with which I'm not so sure I agree. I Am Not An Isp www.ianai.net "Think of it as evolution in action." - Niven & Pournelle