[c-nsp] ibgp prefix advertisement

Dave Temkin dave at ordinaryworld.com
Tue Aug 8 09:57:33 EDT 2006


You need to disable synchronization on CUSTOACCESS (no sync in router
bgp).

Rules of iBGP say every speaker must be meshed.  In your setup, they don't
really *need* to be, and to overcome this you must disable sync.
The correct method, however, would be to enable a session directly between
CUSTOACCESS and IXROUTER.


-Dave

On Tue, 8 Aug 2006, Mikisa Richard wrote:

> Hi all,
>
> Scenario
>
> AS29032--ebgp--CUSTOACESS(41.220.15.253)--ibgp--CUSTODIST(41.220.15.250)--ibgp--IXROUTER(41.220.15.252)
>
>
> Problem is that CUSTODIST receives prefixes from CUSTOACESS but does not
> advertise them to IXROUTER.
>
> from CUSTODIST ....
>
> distro#show ip bgp su
> BGP router identifier 41.220.15.250, local AS number 28941
> BGP table version is 231, main routing table version 231
> 29 network entries and 30 paths using 3893 bytes of memory
> 8 BGP path attribute entries using 480 bytes of memory
> 5 BGP AS-PATH entries using 120 bytes of memory
> 0 BGP route-map cache entries using 0 bytes of memory
> 0 BGP filter-list cache entries using 0 bytes of memory
> BGP activity 78/633 prefixes, 105/75 paths, scan interval 15 secs
>
> Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down
> State/PfxRcd
> 41.220.15.252   4 28941     388     370      231    0    0 00:25:14       25
> 41.220.15.253   4 28941     953     949      231    0    0 15:46:40        5
>
>
> distro#show ip bgp ne 41.220.15.253 ro
> BGP table version is 231, local router ID is 41.220.15.250
> 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
> *>i0.0.0.0          41.220.15.253                 100      0 29032 i
> *>i41.220.0.0/20    41.220.15.253            0    100      0 29032 i
> * i41.220.14.0/23   41.220.15.253            0    100      0 i
> *>i217.212.230.0/23 41.220.15.253                 100      0 29032 i
> *>i217.212.242.0/23 41.220.15.253                 100      0 29032 i
>
> Total number of prefixes 5
>
> distro#show ip bgp 217.212.242.0
> BGP routing table entry for 217.212.242.0/23, version 206
> Paths: (1 available, best #1, table Default-IP-Routing-Table)
>    Not advertised to any peer
>    29032, (received & used)
>      41.220.15.253 (metric 11) from 41.220.15.253 (41.220.15.253)
>        Origin IGP, localpref 100, valid, internal, best
>
>
> distro#show ip bgp ne 41.220.15.252 ad
> distro#
>
>
> Any ideas on why CUSTODIST is not advertising?
>
>


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