[j-nsp] OSPF next hop

[Aaron Dewell]

On Jul 24, 2012, at 2:04 PM, Wayne Tucker wrote:
> On Tue, Jul 24, 2012 at 12:36 PM, Aaron Dewell <aaron.dewell at gmail.com> wrote:
>> Yes, Type Transit (2).  However, the Network LSA only includes 3 attached routers (should be 6 currently).  There are two Network LSAs in R7.  One has the interface IP of R1 (non-DR/BDR) with 3 attached routers (R1, R5, R6).  The other has the interface IP of R2 and shows 3 attached routers (R2, R7, and R8).  The interfaces on R3 and R4 are currently shut down.
>> 
>> Further looking into it, there is disagreement all across this network about who is the DR and BDR.  Half the routers show one set, and half show the other.  I think that might produce some issues!
> 
> Wow, that is weird.  If L2 communication is good across the segment
> then MTU or authentication mismatch would be my next guess.
> 
> It might be worth turning on OSPF tracing, if you haven't done so already:
> 
> set protocols ospf traceoptions file ospf-trace.log size 2m files 2
> world-readable
> set protocols ospf traceoptions flag error detail
> 
> There are other flags available, but I've found that "error detail"
> almost always provides me the information I need.  At the same time,
> it's pretty quiet under normal conditions (so I leave it enabled on
> most of my OSPF routers).
> 
> :w

This is a shared segment across a layer 2 provider, and at this point, we think it's partial connectivity across them.  I think the routers are behaving properly given a semi-random connectivity on this supposed broadcast segment.

The initial symptom just threw me.  :-)  

Aaron