From: Perminder Grewal (percy_gunner@xxxxxxxxxxx)
Date: Tue Nov 13 2001 - 12:40:16 GMT-3
Ajit
I believe RTA is advertising network 172.16.220.0/24 via IGP (ospf),so
destination 172.16.220/24 will be in RTF route table via next hop
172.16.1.1, this route is not suppressed in an ospf update, but is in a BGP
update as shown in BGP table for RTA. Then in RTF he has a statement under
router bgp 3 network 172.16.220.0 mask 255.255.255.0 (origin igp) which
syncs with IGP ie RTF route table for network 172.16.0.0/24(ospf)(even
though he has no sync command enabled) then BGP process place's that as a
best route in the BGP table for RTF.
Note ospf is running in this set-up as he does state he has left out some
configs too save time/space.
regards
Percy
>From: "Thekkethala" <thek@mediaone.net>
>Reply-To: "Thekkethala" <thek@mediaone.net>
>To: <ccielab@groupstudy.com>
>Subject: Clarification : BGP Aggregation
>Date: Mon, 12 Nov 2001 20:30:45 -0500
>
>This is with respect to the configuration on Page 351-353 of Halabi's book
>regarding Aggregation with a subset of more specific routes.
>
>Not clear on how the objective is being reached ??
>
>The question ?
>
>1. RTR A is using a suppress map for 172.16.220.0 and therefore not
>advertising out to any peer.
>
>So how does Router F get to know abt this subnet ?? (even though RTR F
>config
>has a network staement for 172.16.220.0 ... it is not relevant is it cause
>it
>does not originate form there ??)
>
>2. Therefore how can Router F advertise this out via its EBGP when its NOT
>EVEN present in its BGP table on account of Router A's suppress map on for
>this subnet ???
>
>Am I missing something basic ?????/
>
>thanks ....still wondering hhhhmmm !!
>
>Ajit
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