VPLS WAN scenario

nkariyawasam · ‎09-03-2008

Is it possible to deploy a single subnet for entire WAN using VPLS links ( p2p ethernet) for a large branch setup ?

What is the best practice ?

Giuseppe Larosa · ‎09-03-2008

Hello Nalaka,

I hope I have understood your question correctly.

Your question could be : is it wise to have many remote sites branch reachable via a single IP subnet ?

There are some drawbacks: some routing protocols like OSPF or EIGRP have limitations on the maximum number of neighbors that can be in the same broadcast domain for the way they work.

Control of multicast traffic flowing to the branches can be minimum if all of them are in the same subnet.If a multicast group has to be sent out on the VPLS attached interface it can reach all the sites even if not necessary.

QoS application also can be a problem: using hierarchical qos with two levels of service policy can be a problem on the hub routers if the number of remote is 200 or more.

On the other hand if remote sites need any-to-any connectivity it will be there.

But usually remote sites need to talk much more with headquarters to contact company wide servers of any kind.

I would suggest to use multiple subnets if the number or remote sites is more then 40.

Hope to help

Giuseppe

nkariyawasam · ‎09-03-2008

Hi Guiseppe,

Many thanks for the very usefull update. Yes you have understood my question correctly.

Yes I understand that it could be a problem with large number of spoke routers. But , what I thought was something like follwos;

If I have 200 remote branches, rather than to have 200 differant VPLS instances one per each branch , I can have few VPLS instances, for example, I can have about 40 remote branches in one single VPLS subnet.

In this way I can avoid large numbers of VPLS instances creation at the head office.

Any thoughts on this ?

Giuseppe Larosa · ‎09-04-2008

Hello Nalaka,

I think you can do so the exact number of remote sites per VPLS depends on your routing protocol choice.

Thanks for your good remarks

Hope to help

Giuseppe

tommerola · ‎03-07-2014

Hi Guiseppe

Is there a basic 1921 routing config for Time Warner Cable's ELAN (any to any) VPLS network you can forward or display?

I have 5 Cisco 1921 all on a common VLAN.