Frame-relay and OSPF fuly meshed network need feedback.

[allan.wells]

Hi all,

I'm after some suggestions as to the optimum way to configure OSPF and frame-relay full mesh.

Its getting a little hot in the lab at the moment [:|

Should you use sub interfaces and assign different network addresses + IP ospf network broadcast on sub int ? I have done this and it created a severe state of brain lock due to lingering loopbacks that i didnt remove so the multiple DR/BDR was a little hard to digest!!

Or would you just use 1 physical interface and let the DLCI's get assigend to that physical Interface.(assuming one provider telco providing the services) and again use the IP ospf network statement.

I see the sub interfaces as being good for assiging traffic shaping polices which you couldnt do on a physical int with multiple dlci's ?

On the other hand using different network addresses on sub interfaces seems more complex and not idealistic ?Would you just assign /30 to each different sub interface ? Or is this completely of the wall thinking...

This is an example of what of the full mesh NBMA network running OPSF I have setup in the lab and would appreciate your suggestions.

Not directly related though I'm looking for clarification on this..

One more thing I not clear on is how do you know that a NBMA enviroment doesnt support

multicast and when it does ?

Some layer 2 support multicast broadcast capabilty some dont i.e the need for ip ospf network point-to-multipoint nonbroadcast

R1 s1.1 1.1.1.1 255.255.255.252 dlci 100-->101 r2

s1.2 2.2.2.1 255.255.255.252 dlci 200-->202 r3

R2 s0/0.1 1.1.1.2 " " dlci 100-->101 r1

R2 s0/0.2 4.4.4.1 " " dlci 400-->402 r3

R3 s0/1.1 2.2.2.2 " " dlci 202-->200 r1

R3 s0/1.2 4.4.4.2 " " dlci 402-->400 r2

Cheers

Allan Wells

[ruwhite]

I've always preferred creating subinterfaces for handling NBMA in OSPF, though there are, at least, for different ways to handle it.

-- non-broadcast, with configured neighbors, on the main interface

-- broadcast, with set priorities, on the main interface

-- ospf network-type point-to-multipoint

-- create subinterfaces

It just seems cleaner to me to run subinterfaces. I would assign a /31 to each subinterface, or make them all unnumbered to a loopback, if I was really desperate (although unnumbered brings it's own set of problems to the table).

I don't know that there is any general rule to NBMA clouds supporting multicast or not.... I've not seen one that didn't support multicast, or at least wan't supposed to support multicast. What I normally do is to make certain ospf, eigrp, or some other protocol is running that would make the router listen to a link local multicast address, and then ping that address. For instance, if you have ospf running, ping 224.0.0.5. For eigrp, try 224.0.0.10.

Russ.W