Re: BGP Route Reflector with Synchronization ON

If you have BGP routes not in IGP such as OSPF, you should turn OFF BGP
synchronization.
For an example, if you peer with EBGP and/or your router is working as
transit router from BGP viewpoint, you have to turn off.

BGP sync will check IGP routing table, and if it is not in there, BGP
will not install those BGP prefix for active entry.

Alex

Divin Mathew John wrote:
> Hey...
> i have this scenario where R5-----R6-----R7 and R7 is connected to
> R5 for redundancy.! now. I made R5 the Route Reflector. and i have
> OSPF running with all the loopbacks advertised in OSPF. Now without
> turning ON Synchronization this is the output
> R6#sh ip bgp
> r>i5.5.0.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.1.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.2.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.3.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.4.0/24 5.5.0.5 0 100 0 ?
> r>i7.7.0.0/24 7.7.0.7 0 100 0 ?
> r>i7.7.1.0/24 7.7.0.7 0 100 0 ?
> r>i7.7.2.0/24 7.7.0.7 0 100 0 ?
> r>i7.7.3.0/24 7.7.0.7 0 100 0 ?
> r>i7.7.4.0/24 7.7.0.7 0 100 0 ?
>
> where as in Switch ON Synchronization @R6
>
> r>i5.5.0.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.1.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.2.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.3.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.4.0/24 5.5.0.5 0 100 0 ?
> *> 6.6.0.0/24 0.0.0.0 0 32768 ?
> *> 6.6.1.0/24 0.0.0.0 0 32768 ?
> *> 6.6.2.0/24 0.0.0.0 0 32768 ?
> *> 6.6.3.0/24 0.0.0.0 0 32768 ?
> *> 6.6.4.0/24 0.0.0.0 0 32768 ?
> * i7.7.0.0/24 7.7.0.7 0 100 0 ?
> * i7.7.1.0/24 7.7.0.7 0 100 0 ?
> * i7.7.2.0/24 7.7.0.7 0 100 0 ?
> * i7.7.3.0/24 7.7.0.7 0 100 0 ?
> * i7.7.4.0/24 7.7.0.7 0 100 0 ?
>
> @R7 SYN is OFF
> r>i5.5.0.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.1.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.2.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.3.0/24 5.5.0.5 0 100 0 ?
> r>i5.5.4.0/24 5.5.0.5 0 100 0 ?
> r>i6.6.0.0/24 6.6.0.6 0 100 0 ?
> r>i6.6.1.0/24 6.6.0.6 0 100 0 ?
> r>i6.6.2.0/24 6.6.0.6 0 100 0 ?
> r>i6.6.3.0/24 6.6.0.6 0 100 0 ?
> r>i6.6.4.0/24 6.6.0.6 0 100 0 ?
> *> 7.7.0.0/24 0.0.0.0 0 32768 ?
> *> 7.7.1.0/24 0.0.0.0 0 32768 ?
> *> 7.7.2.0/24 0.0.0.0 0 32768 ?
> *> 7.7.3.0/24 0.0.0.0 0 32768 ?
>
> I turn OFF SYN at R6 and everything has a RIB failure.. becoz OSPF is
> running advertising all the loopbacks.!
>
> Is there any special thing to be noted while using SYNC with Route Reflectors.!
>
> Generally SYNC is OFF.. Just out of curiosity.!
>
>
> Thanking You
>
> Yours Sincerely
>
> Divin Mathew John
> divinjohn_at_gmail.com
> divin_at_dide3d.com
> http://www.dide3d.com
> +91 9945430983
> +91 9846697191
> +974 5008916
> PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt
> Sent from Bangalore, KA, India
>
>
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Received on Wed May 13 2009 - 12:35:44 ART