Ubigate iBG2016 Configuration Guide/Ed.00© SAMSUNG Electronics Co., Ltd. 147MPLS ForwardingMPLS forwarding consists of 3 main operations:1. Mapping of data packets into LSPs based on destination FEC bypushingMPLS labels. For Martini case, a VC label followed by a tunnel labelwill be pushed.2. Switching of MPLS labeled packets by swapping the incoming MPLSlabels with pre-agreed outgoing label.3. Forwarding of MPLS packet as L3 packets by popping the MPLS labelat the PHP HOP or at the egress LER. For Martini case, forwarding ofMPLS packet as L2 packets by popping the MPLS outer label, andexamine the inner VC label.The MPLS architecture defines the components of the forwardinginformation base(FIB) as follows:y Next Hop Label Forwarding Entry(NHLFE): An entry containing next-hop information(interface and next-hop address) and labelmanipulation instructions; it may also include label encoding, L2encapsulation information, and other information required forprocessing packets in the associated stream.y Incoming Label Map(ILM): A mapping from incoming labels tocorresponding NHLFEs.y FEC-to-NHLFE map(FTN): A mapping from the FEC of any incomingpackets to corresponding NHLFEs.y Existing FIB design must be enhanced to support the FTN and ILMtable for MPLS packet forwarding.
