Conclusion

Fast ReRoute IP solutions have been developed over the last fifteen years to protect traffic in 50 ms following a link or node failure. The problem is a difficult one, since IP routing needs to be bypassed, and IP has no tool for doing so.

LFA is a simple and easy solution, but only provides a partial solution. What's more, the protection coverage rate and the details of protected and unprotected destinations are not easy to determine without simulation, and they change with every change in network topology.

RLFA improves LFA's coverage rate to almost 100%, but introduces complexity through the dynamic addition of tunnels. It may also require additional configuration to guide the choice of an RLFA that respects the operator's routing policies.

The latest addition, TI-LFA, has good properties: it can protect all destinations...