MPLS-Enabled Applications: Emerging Developments and New Technologies

3.10. DEPLOYMENT CONSIDERATIONS FOR LOCAL PROTECTION MECHANISMS

Service providers are attracted to MPLS FRR by the promise of fast and predictable recovery times. However, the challenges of deploying it, its cost and the guarantees it can deliver in a real deployment are not always well understood. This makes it difficult to make the correct tradeoff between costs and benefits. In the following sections we discuss some of the deployment issues for MPLS FRR.

3.10.1. Scalability considerations

Local protection comes at the cost of setting up extra LSPs in the network. In the Traffic Engineering chapter (Chapter 2) we saw that the number of LSPs is a scalability concern, both because the routers themselves have limits on the number of LSPs they support and because a large number of LSPs in the network is cumbersome to manage. In the context of protection, another scaling dimension is the amount of extra forwarding state created along the protection path. Let us take a look at several of the scalability aspects of local protection.

3.10.1.1. Extra configuration work

One of the prevailing misconceptions is that local protection is operationally very difficult to deploy and manage. This belief has its origins in some of the early implementations of local protection which required listing the protection paths in the configuration. Apart from being labor intensive, this approach also required that the computation of the path be done offline, either manually or by using a specialized ...