I have
a solution for this problem.
Basically
if any LSR receives an Label withdraw message from its valid Next hop neighbor
then before propagating to its upstream peers it need to check the value of
the label being withdrawn, if the label happens to be an NULL label then it
should not propagate the label withdraw to its upstream peers. Now this LSR
should now assume itself as an egress for that LSP.
[Vijayanand C - CTD,
Chennai.] What will happen in valid cases when the eggress actually
wants to withdraw label and when u no longer want to switch for that FEC
?The pennultimate hop should not hold the label in that case.
How will the Phop know for which case the withdraw applies
?
Second
one could be there should be a provision to change the label for the
particular FEC. I.e any point of time the valid next hop LSR can advertise a
change of label for that FEC. Here problems are we need to maintain the
context of that advertisement (LM).
[Vijayanand C - CTD, Chennai.] This
becomes unsolicited advertisement.
A better way would be for the
egress to withdraw the label. However the ingress will not issue a
request unless it is in Independent control. This anyway is
a problem. My suggestin would be - The ingress after sending a release
can issue a fresh request for the label even if its not in independent
control if it still supports label switching on the FEC. I feel
This would be more cleaner .
Vijay