In message <9410132230.AA21917@msf.psi.net>, "Mark S. Fedor" writes:
Again I would like to draw to your attention the fact that some destinations are apparently being originated by more than one AS. These show up in the report with more then one origin. I was under the impression that thsi is an illegal or highly undesireable configuration; I would still like to hear some comments on this issue.
This is not illegal by the BGP RFC, but it is basicly frowned upon by operators and the BGPd community. This usually occurs when people are back-leaking redistributing IGP's into different BGP ASs.
If you were homed to the NSFNET in two different places, you needed unique AS's at each peering point. So you had to dump your nets into two different AS's. I realize this recently changed, but why deal with it now, when it will soon go away.
mf
Mark, This has not been the case for about 1/2 year now. You can border in two places with the same AS number. Even when it was the case, you should still provide the same home AS, just different border AS somewhere in the path. Other providers manage to do this. Curtis