mLDP FEC type 1

mLDP defines several FEC (Forwarding Equivalence Class) types for P2MP LSPs. SR Linux supports only the basic FEC with opaque type 1. Because only basic FEC type 1 is supported, mLDP operates within a single IGP area without Area Border Router (ABR) or Autonomous System Border Router (ASBR) transit for recursive FEC types.

In the following figure, SR Linux can serve as the root node for both inter-AS and intra-AS networks because mLDP advertises only a basic (type 1) FEC in the root area. Consequently, any complex recursive FECs are simplified and reduced down to this basic type 1 FEC format at the root level.