Where the payload of a pseudowire comprises a number of distinct
flows, it can be desirable to carry those flows over the Equal Cost
Multiple Paths (ECMPs) that exist in the packet switched network.
Most forwarding engines are able to generate a hash of the MPLS label
stack and use this mechanism to balance MPLS flows over ECMPs.
This document describes a method of identifying the flows, or flow
groups, within pseudowires such that Label Switching Routers can
balance flows at a finer granularity than individual pseudowires.
The mechanism uses an additional label in the MPLS label stack.
[STANDARDS-TRACK]