Uhm but an AS-path is a trail of bread-crumbs to prevent an announcement
loop, not a proper predictor of the forwarding-path towards the origin.
Indeed, because of hop-by-hop routing, the ultimate destination may
have nothing to do with the originating AS. Fun fun fun!
Consider what happens when, at an IX, one of the ASes in an AS path
gives you someone else's router address as a next-hop...
Sean.
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Jared Mauch wrote:
second, if they (AS5662) were connected to MCI/CW rather than
Sprint, they would be unreachable with this announcement, other
than the fact that ANS would be announcing the aggregate, and following
that path, rather than having the actual as-path be traversed.Uhm but an AS-path is a trail of bread-crumbs to prevent an announcement
loop, not a proper predictor of the forwarding-path towards the origin.
but, as jared was talking about filtering of routes, forwarding path is
quite irrelevant.
randy