5. When the Resv message reaches the ingress LSR, the LSP setup is complete.
RSVP-TE has also been extended to enable it to create point-to-multipoint LSPs, which
may also be traffic engineered. The LSPs created are analogous to the trees created by
PIM-SSM in IP multicast. P2MP RSVP-TE is useful for applications such as multipoint
video distribution or multicast VPLS (see section on IP Multicast in VPLS below).
BGP Signalling BGP is used by service providers as an exterior gateway protocol (i.e.,
to distribute routes to other service providers and to carry external routes within each
service provider??™s network). RFC 2858 defines multiprotocol extensions to BGP, and
RFC 3107 builds on this by defining how to advertise labelled routes using BGP. In RFC
3107, a label for FEC is piggy-backed on the BGP update message used to advertise
the FEC itself.
BGP is used to signal the VPN labels used in the RFC 2547 standard for implementing
IP VPNs over MPLS (now updated in RFC 4364), but it may also be used to advertise
labelled FECs between different autonomous systems within one service provider??™s
network or between service providers.
Pages:
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961