Below are some notes from my CCIE written. Hope you enjoy them

MPLS IP Forwarding: Data Plane

– MPLS routers inject (push) or remove (pop) or forwards packets based on labels
– MPLS relies on the CEF while expanding the logic and data structures as well

LSR (Label Switch Router)

– any router that has awareness of MPLS Labels
FIB – used for incoming unlabled packets
LFIB – used for incoming labeled packets

MPLS header and Label
– header of 4 bytes, located before the IP header

MPLS header
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