OSPF network type over global VPLS network

[tbogucki1]

What is the best choice of ip ospf network type to use to run OSPF over global (15 sites) VPLS network?

My understanding is:

ip ospf network:

P-t-m n-b – no DR/BDR election, neighbor command required, partial mesh adj, non-optimal traffic flow

P-t-m      –  no DR/BDR election, no neighbor command required, full mesh adj, optimal traffic flow

Broadcast –     DR/BDR election, no neighbor command, Hub-Spoke adj, optimal traffic flow

Which OSPF network type should be used and why?

Are there some examples of deployment of OSPF over global VPLS network?

What should be considered to deploy such a scenario?

Thanks

Tom

[Marwan ALshawi]

is your topology hub and spoke ? or not

i would say p-t-m is goo doption to go with but the queston here can the underlaying VPLS pass the multicast of p-t-m

if yes then use it if not then use p-m-p-nb

HTH

if helpful Rate

[tbogucki1]

We have 4 main hubs and the rest are branch offices.

Yes I believe VPLS can pass the multicast for p-t-m topology.

With p-t-m there will be full mesh of OSPF adj, which do not look to be a very scalable solution.

I think it is the choice between Broadcast and P-t-M non-broadcast

with Broadcast network type there will be DR/BDR election

with P-t-M N-B, there must be a neighbor command configured manually.

I am leaning towards p-t-m n-b and we can create full mesh between 4 hubs and the branch offices will connect to the closest hub.

Can somebody also agree with that? Did somebody have experience with similar scenarios/choices?

Thanks

[Peter Paluch]

Hello Tomasz,

The VPLS essentially provides you with a multiaccess segment on which every member can communicate with all other members directly. There should be no partial connectivity as in Frame Relay partially-meshed VPNs, for example. The VPLS should behave for you essentially like a huge switched Ethernet segment.

Because of this, I see no reason to have hard feelings about the OSPF network type. My personal opinion that the Broadcast network type would be just fine for this example. Using PtMP would certainly work but I see no advantages in using it here. The PtMP is best used in partially-meshed environments. The PtMP NB would be an additional complication here because of the need to specify all neighbors manually. Unless you would need to specify separate costs for each neighbor on a multiaccess segment, using the PtMP NB would unnecessarily complicate things.

Best regards,

Peter

[t.bratinov]

Peter, there are already some cases why not to use Broadcast over VPLS.You can see example of what happens here.

http://ieoc.com/forums/t/16073.aspx.