[c-nsp] DMVPN and OSPF

[Rodney Dunn]

Jay Nakamura wrote:
>> Did you force the DR to be the hub by setting the priority?
> 
> Yes.  And confirmed.
> 
>> I forgot, did you set it to broadcast or multipoint?
> 
> broadcast
> 
>> I'd suggest you look at the packet capture feature and get a trace when it's
>> down.
> 
> Is this what you are referring to?
> 
> http://www.cisco.com/en/US/docs/ios/12_4t/12_4t11/ht_rawip.html#wp1049404
>

No this one:

http://supportwiki.cisco.com/ViewWiki/index.php/Tech_Insights:Utilizing_the_New_Packet_Capture_Feature



> There is no tech onsite and it's a little far so I can't do it at the
> moment but if I can't figure out anything else, that will be the next
> step.
> 
>> Do you see the LSA's in the database?
> 
> I believe it was blank.  It's working now after a reboot so I can't
> check but I will check next time it happens.
> 

Ok. That is the starting point if the neigbors are not flapping.


>> Can you ping 224.0.0.5 and get a response?
>>
>> Are the neighbors flapping?
> 
> It didn't flap at all.  Routes just disappeared.  Well, that's not
> 100% true.  The backup hub VPN connection went down and it wouldn't
> come up.  I could ping the primary hub tunnel IP when the routes were
> gone but none of the other DMVPN peer IP.
> 

Almost always issues like this are with packet loss. You have to make 
sure the multicast traffic can traverse the cloud and that requires 
replication at the hub..and the spoke if you are doing a single spoke 
tunnel with dual hubs.


> 
>> Jay Nakamura wrote:
>>> Has anyone seen this symptom?
>>>
>>> 1841, advanced IP feature set
>>> DMVPN spoke and OSPF over the DMVPN
>>>
>>> Running 12.4(24)T
>>>
>>> Periodically, the router looses all it's OSPF routes and stays that
>>> way.  Clearing the DMVPN or OSPF process does nothing.  It recreates
>>> the OSPF session with neighbor but it still has no routes.  It can't
>>> seem to re-connect to the backup DMVPN hub either.
>>>
>>> Router still routes to the static default route for internet traffic
>>> and everything else seems normal.  Just can't get to the VPN network.
>>>
>>> It's really not doing anything fancy other than DMVPN and OSPF.
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