Re: Timing of the upstream data path establishment

[Harry Mantakos <harry@meretrix.com>]

>I don't think that this is an issue.  Suggested label allows a node to begin
>to establish the forward direction as it progresses the Path message.  Since
>it controls the labels in the reverse direction, it can also begin to
>establish the reverse direction concurrently.

As I understand it, suggested label allows a single node to do
whatever hardware preparation is required for the upstream and
downstream data flows in parallel, but this preparation is
still necessarily done at each node in the path sequentially.
If it takes 'T' time to prep hardware for a single direction at a
single node, and there are 'N' nodes, you're looking at something
on the order of TN to establish the LSP. In the absence of suggested
label, you'd be looking at something like 2TN.

The suggested "3-way handshake" allows "preparation" to be done
at all nodes in the path in parallel. The circuit establishment
time can be reduced to something on the order of T (assuming suggested
label was chosen).
-harry