From: Mark Lewis (markl11@xxxxxxxxxxx)
Date: Mon Feb 04 2002 - 12:43:21 GMT-3
Hi,
BGP split horizon is quite different to RIP/EIGRP/etc split horizon. BGP
split horizon is as follows: an iBGP update received by a router will not be
advertised onwards to another iBGP neighbor. The reason for this is that the
mechanism that BGP uses to detect loops is the AS_PATH attribute (in the
absence of RRs & cluster-IDs, etc.). Within an AS this is not modified, so
there is no way to detect whether a loop is developing.
This is standard whether you are using Cisco or Juniper or whatever.
Hope that helps,
Mark
CCIE#6280 / CCSI#21051 / JNCIS
>From: John Neiberger <neiby@ureach.com>
>Reply-To: John Neiberger <neiby@ureach.com>
>To: "David" <dave_murphy_1@excite.com>
>CC: ccielab@groupstudy.com
>Subject: Re: Junos BGP routes update
>Date: Sun, 3 Feb 2002 23:46:18 -0500
>
>It's my understanding that this is also Cisco's implementation,
>and that it was up to the receiving router to analyze the AS-
>PATH and drop an update if it saw its own ASN.
>
>I'll have to double check this, but I'm about 75% sure that
>this is how Cisco behaves, as well.
>
>John
>
>
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