01-12-2016 12:22 PM - edited 03-08-2019 03:22 AM
In troubleshooting OSPF IPV6 routing on C4500x switches (entservice license) having only Area0 backbone, the routes are being propagated ok but I see the <show ipv6 ospf neighbor> output reflects all neighbors in the FULL state -No DR/BDR. Could this possibly be a correct status or is it an indication that IPV6 OSPF routing is not configured properly/ working correctly?
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01-12-2016 12:48 PM
Steve, Jon,
No need to add anything here. As Jon has explained, because of the point-to-multipoint network type, no DR/BDR elections are taking place.
Do you have an idea why these routers are configured for point-to-multipoint OSPF network type? This is not very usual especially over Ethernet VLANs - and I also dare to say that for Ethernet environments with full visibility between all attached routers, running point-to-multipoint OSPF makes little sense.
Best regards,
Peter
01-12-2016 12:27 PM
Hello Steve,
Posting the show ipv6 ospf neighbor output would have been helpful - but from what you write, it seems as if the interfaces were configured for a OSPF network type that does not elect DR/BDR, either point-to-point or point-to-multipoint. Would this be the case?
With these network types, the absence of DR/BDR is expected. Whether, however, those network types are used properly in your network is another question, and for that, we would need to know more about the topology.
Best regards,
Peter
01-12-2016 12:33 PM
Peter
Sorry, got distracted while posting and in the meantime you provided an answer.
Jon
01-12-2016 12:36 PM
Jon,
I am glad we have both responded :) This is all to Steve's benefit. And we may actually open up a nice can of worms if we touch something interesting in this particular case :-P
Best regards,
Peter
01-12-2016 12:38 PM
And we may actually open up a nice can of worms if we touch something interesting in this particular case
We can only hope although I'm not sure Steve would agree :)
Jon
01-12-2016 12:40 PM
Paul
#sh ipv6 ospf neighbor
Neighbor ID Pri State Dead Time Interface ID Interface
x.x.22.14 0 FULL/ - 00:01:45 51 VlanX
x.x.157.17 0 FULL/ - 00:01:35 2225 VlanY
x.x.201.15 0 FULL/ - 00:01:39 2225 VlanY
x.x.254.33 0 FULL/ - 00:01:59 27 VlanY
x.x.254.132 0 FULL/ - 00:01:57 39 VlanY
x.x.22.14 0 FULL/ - 00:01:35 50 VlanX
x.x.157.17 0 FULL/ - 00:01:55 2224 VlanX
x.x.201.15 0 FULL/ - 00:01:54 2224 VlanX
x.x.254.33 0 FULL/ - 00:01:47 26 VlanX
x.x .254.132 0 FULL/ - 00:01:41 38 VlanX
All of the IPV6 ospf interfaces have this config applied: <ipv6 ospf network point-to-multipoint>
01-12-2016 12:45 PM
Peter will probably give you a much better answer than me but what you are seeing is correct because with point-to-multipoint OSPF treats the links as point-to-point links and no DR/BDR is elected on those.
Jon
01-12-2016 12:48 PM
Steve, Jon,
No need to add anything here. As Jon has explained, because of the point-to-multipoint network type, no DR/BDR elections are taking place.
Do you have an idea why these routers are configured for point-to-multipoint OSPF network type? This is not very usual especially over Ethernet VLANs - and I also dare to say that for Ethernet environments with full visibility between all attached routers, running point-to-multipoint OSPF makes little sense.
Best regards,
Peter
01-12-2016 02:02 PM
Thanks gentlemen you are correct the point-to-multipoint configuration was a legacy configuration, I lab tested and see DR, BDR DROTHER /FULL/.. -rolled out the change into production
looks much better now
01-12-2016 12:51 PM
Do you have any vlans/IP subnets with multiple neighbors or is it all P2P links ?
If P2P links have you got "ipv6 ospf network point-to-point" under the interfaces ?
Jon
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