The MPLS WG Archive

[Chris Kuszmaul <fyodor@pluris.com>]

 Before a label can be mapped to an FEC that has already been mapped, the LSR
must release the old label (prompted perhaps by a withdrawal message). Thus, LDP
calls for a break-before-make on LSP updates.  It would seem a straightforward
matter for the protocol to include a withdraw-and-map message that performs this
sequence atomically, and so preserves a make-before-break condition.

  Is there some reason for not providing for this kind of functionality?

 Thanks for any comments.

CLK

PS: The careful reader will realize that I have mentioned this issue before in
the thread [Re: Receive Label Receive !!], but have not seen any reply. This is
an attempt to focus the question and broaden the pool of possible respondents.