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Re: RIP is preferred over eBGP! posted 09/27/2007
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Gregory,

Step 1: Router B is faced with two BGP sources, ebgp and locally originated
(redistributed from RIP).

BGP decision process will pick the locally originated over the ebgp route
(Wendel Odom)

W - weight
L - local preference
L - locally originated
A - AS path

O - Origin
M - MED
N - Neighbor Type
I  - cannot remember :)


Step 2: BGP administrative distance for locally originated is 200, for RIP
120. RIP therefore wins.

In case I've got the sequence figured out wrongly, comments are welcome.

Ben






On 9/26/07, Gregory Gombas <ggombas@xxxxxxxxx> wrote:
>
> I'm seeing the following quirk in a production network:
>
>          BGP-->
>          RIP-->
> RTRA----------RTRB
>
> Router A is directly connected to router B and is sending the same
> routes via RIP and eBGP.
> Router B is also redistributing the RIP routes into BGP (but filtered
> from sending back to A)
>
> When you look at the route table on RouterB, it shows the routes as RIP
> routes!
> You would think the eBGP learned routes would be preferred because of
> lower AD.
> But when I look at BGP table it shows the route originated locally and
> thus preferred over eBGP learned route.
> When I clear ip route the route is then shown as a eBGP route in the
> routing table and BGP route table does not show the locally originated
> route!
>
> Just wondering if anyone else has seen this...
>
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