BGP Labeled Unicast

For creating MPLS LSPs, other than RSVP, LDP, and SR, we can also make use of BGP. BGP can advertise transport labels, using a speical address family.

BGP-LU is used to run MPLS VPNs between autonomous systems. RSVP LSP on one AS, may be an LDP LSP on the other AS, BGP-LU in between these two ASs. With this we can achieve an end-to-end LSP between two different domains.

By using BGP-LU, ASBR can advertise a transport label to another AS.