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Demand Circuit in OSPF Virtual Link


I am trying to configure an OSPF Demand Circuit between three areas connected by a virtual link. Here is the setup:

R1 (area 2) -- R2 (Area 1 Area 2) -- R3 (area 2 Area 0) -- R4 (area 0).

The virtual link is between R2 and R3. The ISDN runs between R1 and R4. My question is: when I put the network of the Dialer interfaces on R1 and R4 into OSPF, which area do they have to be part of ? Or is it a limitation of the OSPF Demand Circuit that it cannot span areas ? After all, the same network cannot be part of two areas.

Thanks for your help in advance.



Community Member

Re: Demand Circuit in OSPF Virtual Link

Although I am not familiar with the rest of your network, I don’t see why you have a virtual-link between area2 and area0? I would make R1 and R2 both members in area2 then make area2 totally stubby. The WAN interfaces of R3/R4 would also be in area2, making the LAN interfaces of R3/R4 in area0 (this would make R3/R4 both ABRs). You could then make both WAN links demand-circuit. You don’t mention if ISDN is for backup only or will be used some other way.

Hope this link helps!

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