[Xorp-users] iBGP routes not being used/forwarded

[Russ Dill]

I figured out my issue, I needed to include an empty AS list with my route
instead of including my own AS.

On Tue, Dec 2, 2008 at 11:30 PM, Bruce M Simpson <bms at incunabulum.net>wrote:

> Russ,
>
> We need to see what the RIB thinks about the routes you're introducing from
> your collector daemon.
>
> Russ Dill wrote:
>
>> ...
>>
>> However, no local routes are added:
>>
>> ip route
>> 192.168.1.0/24 <http://192.168.1.0/24> dev eth0  proto kernel  scope link
>>  src 192.168.1.136 <http://192.168.1.136>  metric 2
>> 169.254.0.0/16 <http://169.254.0.0/16> dev eth0  scope link  metric 1000
>> 10.0.0.0/8 <http://10.0.0.0/8> dev mea0  scope link
>> default via 192.168.1.1 <http://192.168.1.1> dev eth0
>>
>> And no updates are sent to the backhaul peer.
>>
>> Both peers are running XORP 1.5-6 from debian.
>>
>>
>
> The most likely explanation for the behaviour you are seeing, is that the
> updates are present in the BGP routing table, but the RIB is not selecting
> them as the candidate paths because of that 10.0.0.0/8 entry, which the
> RIB will learn about from the FEA as a 'connected' route. That's pretty
> clear from the output you've provided.
>
> Note that whilst the iBGP routes are "valid", they are not "best",
> therefore there is absolutely no reason for iBGP to propagate them in
> updates -- unless you do some very specific tweaking using LOCAL_PREF and
> import policies, to cause those routes to win BGP's internal lookup.
>
> You're also going to have to do some tricks with administrative distance to
> get the RIB to choose the iBGP learned routes with the /24 prefixes. XORP
> defaults to an admin distance of 200 for iBGP and 0 for "connected" routes,
> so clearly, the iBGP routes will lose the RIB lookup every time.
>
> I believe the features to control admin distance on a per-protocol basis
> got added in the run up to the 1.5 release -- OLSR certainly makes use of
> them -- although they may not be fully documented until 1.6.
>
> thanks
> BMS
>
>
>
>
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