> Tulip Rasputin wrote: > That's why i explicitly asked for some "social/political/etc." > reasons where an ISP may not want his traffic to traverse some > particular AS number(s). Something which is beyond BGP to > determine as of now ! :-)
FWIW, this is exactly how I understood the question. It's all about "non-BGP" issues. > I believe with the responses that i received both on the list > and offline, that it is indeed quite normal for ISPs to filter > routes based on the AS Paths for 'other' reasons. Reasons, > quite beyond BGP as a protocol to handle! And this can happen, > when an ISP doesnt want its traffic to traverse some AS(es). I'm not sure I agree with "normal", but it is common practice indeed, a significant part being in a <cough> grey <cough> area, and notice that nobody dared to post the reasons on the ML. Trying to stay intellectually honest, there are "good" and "bad" reasons for it. Using my well-known politically incorrect bluntness, I would say this (words borrowed from several people) (disclaimer #2: this is somehow exaggerated, but here it is anyway): God has given men a brain and a penis, but not enough blood to operate both of them at the same time. Although there are exceptions, when the blood flows to the brain, men use BGP; when the blood flows to the penis, men manipulate the AS_PATH and/or create route-maps :-D Michel.