MPLS Traffic Engineering ? Fast Reroute

One of the desirable features of any network is the ability to keep services running after a link or node failure. This ability is known as network resilience and has become a key demand from service providers. Resilient networks recover from failure by repairing them automatically by diverting traffic from failed part of the network to another portion of the network. The traffic diversion process should be fast enough to ensure that the interruption of service due to a link or node failure is either unnoticeable or as small as possible. At the time of failure, new path is taken by diverted traffic through a procedure called Re-Routing. Alternatively the path can be computed before a failure occurs through a procedure called Fast Reroute. In Traditional IP networks best path calculation is done using Re-Routing mechanisms that happen on-demand when a failure is detected, whereas in the proposed system MPLS Traffic Engineering we use Fast Reroute mechanism to provide backup tunnels that can be pre-programmed into the router. This way the best path calculation happens before the failure actually occurs. Fast Reroute protects paths from link and node failures by locally repairing the protected paths and rerouting them over backup tunnels at the point of failure allowing data to flow continuously. In case of a network fault, the fast switchover of protected traffic onto pre-established backup paths happen in a minimal time to minimize traffic loss.