Subject: FEC next hop when FEC has multiple elements

From: Chris Kuszmaul <[email-masked]>
Date: Wed, 02 May 2001 10:44:36 -0700

Having studied the LDP spec., some code that attempts to implement
the LDP spec, and several previous threads on the subject of FEC
aggregation
and deaggragation, I have formulated a little question, for which I am
almost certain of the answer, but there is this nagging doubt.

 In the LDP spec, in appendix A for the receive label mapping
procedure, section A.1.2, page 101, we have:

LMp.11 Determine the next hop for the FEC

 Suppose FEC1 is a set of n FEC elements: F1 and F2 ... Fn.
 Suppose the next hop for F1 is the MsgSource, but for F2 ... Fn it
is something else.
 Suppose (for sake of specificity) we are in downstream unsolicited
ordered
advertisement mode.

 My take is that the next hop for FEC1 is NO ROUTE, and that the
label being mapped is not used for switching/forwarding *at all*.

 If my take is right, then

label_map(label, FEC, otherargs);

 Is not at all like:

for each ELEMENT in FEC:
  label_map(label, ELEMENT, otherargs)

 Unless the next hop for each (or no) ELEMENT is MsgSource.

  So, is my take right?

 Thanks to any who can respond!

CLK