Traffic Engineering with MPLS

Protection Scalability

This section covers how to use Fast Reroute (FRR) link, node, and path protection in your network—specifically, how well it scales.

There's quite a lot to FRR. But the biggest piece people want to get their hands on, after understanding how protection works, is how it scales. If I do link protection everywhere in my network, how many extra LSPs does that give me? What about node protection? Or path protection?

Luckily, the formulae for link/node/path protection are pretty simple. All you need to do is determine the number of additional LSPs each node will have to deal with. You can then add this back into the full-mesh scalability numbers generated earlier in the chapter and see how your design stacks up against your scalability ...