Re: Moving right along ... Switching Type

[Ben Mack-Crane <Ben.Mack-Crane@tellabs.com>]

In reviewing the GMPLS signaling drafts I have been unable to
get a clear understanding of the need for and use of the Switching
Type field in the Generalized Label Request object.

This appears to be an attempt to address LSP setup involving multiple
layer networks, but it does not adequately address the issues involved.

That it "Indicates the type of switching that should be performed on a
particular link." makes it seem to be a local concern, while others
have indicated it is an end-to-end field. For example, George Swallow
says "It is my understanding that for a given LSP it does not change, 
but is carried end-to-end and applies at all intermediate hops along 
the path."

As an end-to-end item I have trouble understanding how the originating node
would determine how to set this (on what basis one determines what switching
choice to make in all cases).  In fact, I'm not sure why the originating
node would care what type of switching is used as long as the LSP is delivered
to the egress faithfully.

Regards,
Ben Mack-Crane