point-to-point on OSPF over Frame-relay

Unanswered Question
May 13th, 2008

Can anybody explain how to get the sub-interfaces to operate in this mode. I've enabled the physical interface which works fine over the frame, but i can't seem to get the actual point-to-point interfaces to communicate. I've got inverse-arp enabled, i've assigned the sub-interfaces their own Ip addresses in the same subnet, OSPF is running across the physical interface, but i've had a brain dead day - so simple i know, but still... Help would be appreciated.

I have this problem too.
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Edison Ortiz Tue, 05/13/2008 - 09:20

Can you ping end-to-end?

Can you provide a portion of the configuration from the routers?



gregg.malcolm Tue, 05/13/2008 - 09:24

2 questions and a request:

1. Can you ping between the 2 P2P int's? If not, a 'show frame map' would be nice.

2. If so, what is the output of a 'sh ip ospf int' cmd?

It would be useful to have:

sh run int

sh run | b router ospf

Richard Burts Tue, 05/13/2008 - 09:36


I can not tell from your original post whether you have configured the frame-relay interface-dlci command under the subinterfaces. It sounds to me like perhaps you have not. If you have not yet done this, then configure this and let us know how things are working.



Giuseppe Larosa Tue, 05/13/2008 - 09:37


having an IP address on the physical interface and some DLCIs used by the main interface.

You should add under the point-to-point subif the command

frame-relay interface-dlci just to be sure that the right DCLI is associated with the the point-to-point subif.

Inverse-arp can tell you than on dlci 100 you ca n reach ip address 10.x.y.z but the LMI information is not aware of subinterfaces.

OSPF uses multicast frames and the frame-relay interface-dlci defines the DCLI as the exit point for every possible type of traffic including broadcast and multicast.

have you added a network area command for the point-to-pointsubif inside the router ospf process?

In defining the point-to-point subif have you specified the point-to-point nature of it ?


inteface ser3/0.100 point-to-point

If all these are defined you should be able to build an OSPF adjacency on the point-to-point subif.

Hope to help


Ibbywannit Wed, 05/14/2008 - 01:18

"frame-relay interface-dlci" - that was the key that i was missing!!

Absolute genius! I love you Giuseppe (in a totally manly way of course :) )

Still the number 1 forum.


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