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BGP |
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| When FECs can be identified with routes to address prefixes and
having deployed routing algorithm which distribute those routes, it can be
argued that label distribution can be achieved by piggybacking the label
distribution on the route distribution. For example, BGP distributes
routes; then, if a BGP speaker needs to distribute also labels to its
BGP peer, it's better to use BGP to do the label distribution
(MPLS-BGP), having this way a scalability advantage over using LDP. |
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RSVP |
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| When RSVP is used to set up resource reservations for a
particular flow, it can be desirable to label the packets in those flows, so
that the RSVP filterspec does not need to be applied at each hop. In
this case, letting RSVP distribute the labels as part of its
path/reservation process is the most efficient method to distribute
them. |
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Explicitly Routed LSPs |
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| In traffic engineering applications, it is desirable to set up explicit
routed paths, from ingress to egress, including also resource reservation
along that path. This can be done by: |
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- Starting with an existing protocol used for setting up resource
reservations, and extend it to support explicit routing and label
distribution. This approach is specified in the protocol
[MPLS-RSVP-TUNNELS].
- Starting with an existing protocol used for label distribution, and
extend it to support explicit routing and resource reservation. This
approach is specified in [MPLS-CR-LDP].
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Important keywords to understand and remember |
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Label Distribution Protocol (LDP)
BGP as LDP
RSVP as LDP
RSVP-TE
CR-LDP |
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