On Mon, 15 Oct 2001, E.B. Dreger wrote:
Let's say that I have transit from 6347 and 2914. Now let's say that I'm stupid, and start advertising routes that I learn from 2914 into 6347, and that 6347 isn't filtering my as-paths or netblocks. [Note: 6347 does know better in the real world.]
Ok, I understand. There was a problem along these lines a few weeks ago. "Sorry guys, a circuit came into service unexpectedly, we hadn't installed any filters yet." (AS#s withheld to protect the guilty.) But then the question is: which is worse, having traffic flow over an inferior path, or taking the chance that two people who both should know better screw up?
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So a community that indicates "you don't want to use this route unless you absolutely have to--trust us" would have been very welcome. Such a community would be especially useful in the face of congestion:
I see and agree. Good idea, IMHO.
But is it worth the trouble to try to "standardize" communities for this?
I should think that this would be trivial. 0x0000:* and 0xffff:* are reserved per RFC1997... release a new RFC with your "you don't want this route!" communities added, participants would benefit, non-participants would observe no change, and there would be no interoperability troubles.
Yes, why not. If anyone has something to contribute or wants to co-author such a draft or RFC, contact me off-list.
I think I like this better than my prior geography-based post... you're suggesting that MED-like info be advertised via standard communities. And who would know better than the originating provider? Makes sense to me...
I've been thinking about other information that could be conveyed in communities. For instance, bandwidth, delay and packet loss. If each router along the way modifies such a community (should probably be an extended one) then a much richer set of information would be available to multihomers to aid in route selection. Iljitsch