Do we still lose packet with fast reroute? One of my students asked me this question. And I would like to share the answer with everyone.
Fast Convergence and the Fast Reroute Network reliability is an important design aspect for deployability of time and loss sensitive applications. When a link, node or SRLG failure occurs in a routed network, there is inevitably a period of disruption to the delivery of traffic until the network reconverges on the new topology.
MPLS Traffic Engineering Fast Reroute Link Protection – I will explain it in plain English and the most important point of MPLS TE FRR Link Protection among other Fast Reroute mechanisms.
BFD is not a fast convergence mechanism. BFD stands for Bidirectional Forwarding Detection. It is an important tool for the IP layer but there is a confusion in the network community about it.
Segment Routing Fast Reroute – Traffic Engineering with Segment Routing uses LFA mechanism to provide 50 msec fast reroute capability. Current Segment Routing implementation for the OSPF uses regular LFA (Loop Free Alternate) for fast reroute in Cisco devices.