IPX and GRE over L3VPN

[mjbriggs]

I have a customer that wishes to fully mesh a 30 site IPX network using the existing L3VPN infrastructure . We intend to encapsulate the IPX within a GRE tunnel BUT can I peer all 30 sites to a "core" VPN router and have this router foward IPX packets to the destination IPX network , this would result in one tunnel on each remote router or will I have to configure 30 tunnels , one for each remote IPX network ? Is there a prefered Cisco solution for this ?

[Richard Burts]

Mike

When you refer to the existing L3VPN infrastructure, is this IPSec with GRE already or is it IPSec and you will be adding GRE to the infrastructure?

There are several options to choose between in designing how to implement the feature for your customer. The traditional approach would be to configure a single GRE tunnel on each remote connecting to the hub router (the hub router would have 30 tunnels, one to each remote). If you configure IPX addresses on each tunnel, then you can route IPX from each remote site to the hub, and from the hub to other remote sites. This is probably the solution that I would choose if I were setting this up.

As you mention there is also an option to configure each remote router with a unique GRE tunnel to each other remote router (as well as one to the hub I guess). In this case each remote router would have 30 tunnels. The advantage would be that each remote could communicate directly with each other remote without requiring the hub to be involved. And it would remove a potential single point of failure at the hub. But full mesh solution do not scale well and I would not want to implement this way for your customer.

There are some other possibilities that you might think about like the possibility of multipoint GRE tunnels which would have the advantage of simplifying the configuration of the hub router. But I would be concerned about issues like split horizon and would personally prefer the point to point tunnel of the traditional approach.

HTH

Rick