From: ying chang (ying_c@xxxxxxxxxxx)
Date: Thu Mar 28 2002 - 00:00:01 GMT-3
Hi,
Not sure if I read the question right. But I think the reason the route is
not selected as the best route is because the route is not learned from IGP,
thus by BGP synchronization rule, it cannot be used as the best route to
avoid black hole. R3 has no problem, because it's not a route that it
learned from IGP.
Chang
>From: Tarek Sabry <tsabry@houston.sns.slb.com>
>Reply-To: Tarek Sabry <tsabry@houston.sns.slb.com>
>To: ccielab@groupstudy.com
>Subject: Route Reflectors again!
>Date: Wed, 27 Mar 2002 19:34:52 -0600
>
>Hi
>
>I have the following:
>
>r8-------r3(rr)--------r2
> |
> eBGP
> |
>r7-------|
>
>
>or basically r3 acting as a RR between r8 and r2 (iBGP) and also having
>eBGP
>with r7.
>
>Now I am trying to do this the hard way (use syncronization) for this lab.
>
>On r2 I have no problem seeing the BGP routes that were originally imported
>from r7.
>
>The problem is that on r2 I cannot get the BGP routes that are reflected
>from r3 to appear as "best path". Basically they appear as "not
>syncronised"
>as you see below. I think that the reason for this is the fact that the BGP
>router ID of the original route is lost by the reflection process and has
>been replaced by "Originator: 10.10.0.8", whci is the ID of the reflector!
>This makes the BGP RID different than the OSPF RID (the latter being that
>of
>r8)! How can I solve this problem by still not changing the
>synchronisation?
>Or can't I?
>
>As you can see below also, the RID of the reflector is the same for BGP and
>OSPF.
>
>Thanks
>Tarek
>
>r2#
>r2#
>r2#sh ip bgp 88.0.0.0
>BGP routing table entry for 88.0.0.0/8, version 0
>Paths: (1 available, no best path)
> Not advertised to any peer
> Local
> 10.10.0.8 (metric 70) from 172.16.1.3 (200.0.0.3)
> Origin IGP, metric 0, localpref 100, valid, internal, not
>synchronized
> Originator: 10.10.0.8, Cluster list: 200.0.0.3
>r2#
>r2#sh ip route 88.0.0.0
>Routing entry for 88.0.0.0/8
> Known via "ospf 1", distance 110, metric 71, type inter area
> Last update from 172.16.1.3 on TokenRing0, 01:41:37 ago
> Routing Descriptor Blocks:
> * 172.16.1.3, from 10.10.0.8, 01:41:37 ago, via TokenRing0
> Route metric is 71, traffic share count is 1
>
>r2#
>--------------------------------
>
>r3#
>r3#
>r3#
>r3#sh ip bgp
>BGP table version is 17, local router ID is 200.0.0.3
>Status codes: s suppressed, d damped, h history, * valid, > best, i -
>internal
>Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
>*>i88.0.0.0 10.10.0.8 0 100 0 i
>r3#
>r3#
>r3#
>r3#sh ip ospf
> Routing Process "ospf 1" with ID 200.0.0.3
> Supports only single TOS(TOS0) routes
> It is an area border and autonomous system boundary router
> ...
>...
>r3#
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