Incoming Label Map (ILM)

The Incoming Label Map (ILM) maps each incoming label to a set of NHLFE's. It is used for forwarding packets that arrive as labeled packets. If the ILM maps a particular label to a set of NHLFE's that contains more than one element, exactly one element of the set must be chosen before the packet is forwarded. Having the ILM map a label to a set containing more than one NHLFE may be useful if e.g. it is desired to do load balancing over multiple equal cost paths.