LSP Control

With Label Switched Path Control the argument was Local Control vs Egress Control of the label switched path.

Egress Method

• originates LSP set up
• LSP setup arrives from correct next hop node and its propagated to all others

Why Egress Method is required for:

• aggregation
• loop prevention
• shutting off LSP
• de-aggregation
• implicit peering
• differential service (ToS / QoS)
• TTL
• MTU
• unique VCI distribution

The attributes from Egress over the Local method of LSP control in terms of messages is 1 message/hop to O(n) messages.

Egress method subsumes Local, that is provides what the Local method does plus more. The alleged advantages of Local that is faster and more robust are very much questionable, in fact it makes no difference since standard protocols use root based routing.

As a conclusion there is no reason for both details can be found in <draft-rosen-mpls-arch>