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Re: honoring AS-path prepend from a peer or customer?
In article <firstname.lastname@example.org> you wrote: : If a peer (or transit customer) prepends their own AS to : their route announcements to you, do you ever strip off : the excessive As'es? That is, do you always honor them : in your announcements to your other customers (or peers)? : I do understand that any operator has full control over : deciding his own outbound policy, regardless of the : AS path. : I want to know what the industry practice is and whether : I should stipulate in my next upstream agreement that : they honor my prepends? : Thanks. Standard practice is to accept them, though you may need to tell the peer or upstream what regexps to allow if they filter by as-path as well as by prefix. (Always a good idea...) My side question is - what shipping routers will let you rewrite AS-Paths by doing anything other than just prepending? Just wondering if any 7007-type horrors are lurking in the wings. I believe Criscos, Bays, and gated boxes can't do this (without BGP->IGP->BGP redistribution). Avi