Given the speed with which fast reroute typically repairs problems (a few milliseconds),
MPLS 429
this is generally easy to ensure. When using BFD in conjunction with backup LSPs (see
section below on backup LSPs), BFD may detect link or node failures faster than the
control plane, but since both BFD and the control plane will take the same action on
detecting a failure, this isn??™t a problem. In general, when using BFD, the upper bound on
the sending rate is determined by the ability of the LSRs to process BFD control packets.
The ITU-T has also defined an MPLS OAM mechanism in Y.1711. Y.1711 is designed
to run end-to-end along an MPLS LSP with a 1-sec frequency. There has also been work
on enhanced OAM mechanisms for MPLS which use elements of Y.1711 and of Y.1731
Ethernet OAM.
Traffic Protection MPLS supports a range of traffic protection mechanisms. Note that
there are two stages to traffic protection??”the fault must first be detected, and then the
traffic must be diverted away from the fault.
LDP-signaled LSPs Because LDP-signaled LSPs follow the IGP, shortest path protection
of these LSPs depends on IGP reconvergence.
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