From: Peter van Oene (pvo@xxxxxxxxxxxx)
Date: Mon Feb 04 2002 - 14:05:53 GMT-3
Issue is likely even simpler and the question stems likely from a variance
in behavior. If A EBGP peers with B, in Juniper, A will send directly back
the B the paths received from B. B then drops per the AS-Path
loop. However, Cisco's implementation will automatically prune these
advertisements in a split horizon like method.
Also, as previously discussed (though maybe on the juniper list?), IBGP
advertisement rules do not constitute a split horizon implementation.
At 10:57 AM 2/4/2002 -0500, John Neiberger wrote:
>That statement is certainly true but I thought we were
>discussing eBGP, not iBGP. I thought he was referring to a
>scenario where an eBGP peer receives an update from another
>eBGP peer that includes its own ASN.
>
>Let's say AS1 has routers A and B, both of which are connected
>to AS2, routers C and D. Both A and B advertise their prefices
>to C and D who in turn trade updates. Then C will advertise
>back to AS1 the routes it learned from D. The receiving router
>in AS1 will see its own ASN in the AS-PATH and drop the update.
>
>I believe that the original poster thought that AS2 wouldn't
>even transmit an update to AS1 that had AS1 in the AS-PATH.
>I'm fairly sure that it is up to the receiving router to check
>the AS-PATH for its own ASN, not the advertising router.
>
>Regards,
>John
>
>
This archive was generated by hypermail 2.1.4 : Thu Jun 20 2002 - 13:46:11 GMT-3