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Mikrotik 3.10 BGP behavior

Posted: Thu Oct 09, 2008 2:56 pm
by trbl
Hello! Currently I'm trying to establish second BGP peering session with my ISP. But it fails, while log shows:
14:38:05 route,bgp,error Duplicate remote RouterId: x.x.x.233 
14:38:05 route,bgp,error     RemoteAddress=x.x.x.165 
How can I resolve my problem?

Re: Mikrotik 3.10 BGP behavior

Posted: Thu Oct 09, 2008 6:55 pm
by changeip
Do you have more than one peer ? If so you are probably connecting to the same router twice or more. 3.14 would also be a good idea.

Re: Mikrotik 3.10 BGP behavior

Posted: Thu Oct 09, 2008 7:43 pm
by trbl
Well I know that I am connecting to the same neighbor router twice. But I connecting to the same router via different interfaces/physical channels, and I need to connect to the same neighbor router twice. But receiving this error.
Unfortunately I've recently upgraded one of my systems to 3.14 and then had a lot of fun :(.

Re: Mikrotik 3.10 BGP behavior

Posted: Thu Oct 09, 2008 10:30 pm
by changeip
the remote side needs to give that 2nd connection a different routerID then.

Re: Mikrotik 3.10 BGP behavior

Posted: Thu Oct 09, 2008 11:08 pm
by trbl
Is there any other choises? Or I need to upgrade to some newer version of Mikrotik?

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 10, 2008 12:17 am
by changeip
nope, BGP wont allow you to have more than 1 peer with the same routerID. Is the remote end not capable of changing the routerID for each peer ?

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 10, 2008 2:16 am
by airnet
Same problem here with v3.14. Just use a different BGP instance per peer that connect to the same duplicate ID router. Should be the same with v3.10 ?

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 10, 2008 12:34 pm
by rpingar
you are not going on the right way.

if you need a second connection to the same neighbor or bgp router, you have to choose the routing-test package and use the recursive nexthop feature that is available only into the test package.

You must have one bgp configuration about the remote neighbor and two static route to reach it.

Regards
Ros

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 10, 2008 4:03 pm
by trbl
Thnx. I've used second bgp instance for the same peer. It works.
But I've received new problem - unable to add the same network to different bgp instances:
> routing bgp network add instance=bgp1 network=x.x.x.0/22 
failure: network with this name already configured
:(

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 10, 2008 4:08 pm
by mrz
In latest version bgp network don't have instance parameter at all.
In v3.14 when you add network it will be used by all instances.

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 10, 2008 8:09 pm
by changeip
be aware that when you have multiple instances that each instance won't see each others routing table entries. ie, ap-path will not be used to compare which route gets used.

Re: Mikrotik 3.10 BGP behavior

Posted: Sat Oct 11, 2008 3:12 am
by trbl
Thnx. I'm planning to upgrade to 3.14.

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 24, 2008 12:35 am
by BrianHiggins
be aware that when you have multiple instances that each instance won't see each others routing table entries. ie, ap-path will not be used to compare which route gets used.

Can you clairify what problems this would cause?

If I am correct in understanding, each instance would simply add the route to the routing table like normal, and it would then be up to the router to determine which route has the least cost as if its a normal route, and not baised on the AS path length (I think that's what you meant by ap-path but I'm not certain)

Re: Mikrotik 3.10 BGP behavior

Posted: Fri Oct 24, 2008 1:48 am
by changeip
correct, as-path isnt taken into account when using separate instances. In my case, I want to use the shortest ap-path which is the main thing with BGP. Something that crosses 5 providers vs being directly on one of my providers goes out the wrong way sometimes.