[j-nsp] Troubleshooting BGP

[Stefan Fouant]

On Wed, Oct 7, 2009 at 10:24 PM, Stefan Fouant <sfouant at gmail.com> wrote:

> On Wed, Oct 7, 2009 at 10:15 PM, Jason Lixfeld <jason at lixfeld.ca> wrote:
>
>> If I'm reading this correctly, the router is preferring the OSPF route
>> over the BGP route, which makes sense because OSPF has a lower
>> administrative distance (is that a Juniper term too, or just a Cisco term?)
>> than iBGP.  This shouldn't prevent the route from being announced to eBGP
>> peers (at least it doesn't in Cisco land, but maybe there are differences in
>> how J and C work in this regard which I'm missing) should it?
>>
>> user at router> show route 69.57.14.0 detail
>>
>> inet.0: 296972 destinations, 664182 routes (296971 active, 0 holddown, 1
>> hidden)
>> 69.57.14.0/24 (2 entries, 1 announced)
>>        *OSPF   Preference: 150
>>                Next hop type: Router, Next hop index: 530
>>                Next-hop reference count: 1262
>>                Next hop: 72.15.49.21 via ge-2/0/1.0, selected
>>                State: <Active Int Ext>
>>                Local AS: 21949
>>                Age: 1:11:22    Metric: 2020    Tag: 0
>>                Task: OSPFv2
>>                Announcement bits (2): 0-KRT 5-Resolve tree 1
>>                AS path: I
>>         BGP    Preference: 170/-791
>>                Next hop type: Indirect
>>                Next-hop reference count: 1
>>                Source: 72.15.48.2
>>                Next hop type: Router, Next hop index: 530
>>                Next hop: 72.15.49.21 via ge-2/0/1.0, selected
>>                Protocol next hop: 206.223.182.67
>>                Indirect next hop: 155101d4 1048579
>>                State: <Int Ext>
>>                Inactive reason: Route Preference
>>                Local AS: 21949 Peer AS: 21949
>>                Age: 1:11:27    Metric: 0       Metric2: 2020
>>                Task: BGP_21949.72.15.48.2+179
>>                AS path: I (Originator) Cluster list:  66.207.194.20
>>                AS path:  Originator ID: 72.15.48.6
>>                Communities: 21949:70 21949:790
>>                Localpref: 790
>>                Router ID: 66.207.194.20
>>
>
> Yep, the OSPF route is preferred, you can see that in your display by
> looking at the * symbol next, which indicates which route is active.  Also
> you can see that the BGP route has an "Inactive reason: Route Preference",
> which makes sense in this case because as you indicate the default
> preference value for OSPF externals is lower than BGP routes.  By default,
> BGP will only advertise active BGP routes.  You'll need to either put in a
> policy to redistribute the OSPF route to BGP, or use the advertise-inactive
> command to advertise the inactive BGP route.
>
> --
> Stefan Fouant
>

BTW, in Juniper land the terminology is "Preference" but for all intents and
purposes it is the same as AD.

Cheers,

-- 
Stefan Fouant