Subject: [mpls] Query on LDP Specification 5036

From: Anil Kumar <[email-masked]>
Date: Mon, 10 Sep 2018 10:41:57 +0530

Hi All,

MPLS Label Space             : Per platform label space.

MPLS label retention mode    : Liberal label retention.

MPLS Label distribution mode : unsolicited downstream.
MPLS Label control mode      : Independent label distribution.

For above modes and configuration i have following queries (understanding
the protocol behavior)

1) When a system should send Label Withdraw message
2) What should be a system's behavior when peer is not responding with
withdraw message.

3.5.11.1 <https://tools.ietf.org/html/rfc5036#section-3.5.11.1>.
Label Release Message Procedures

   An LSR transmits a Label Release message to a peer when it no longer
   needs a label previously received from or requested of that peer.

   An *LSR MUST transmit a Label Release message* under any of the
   following conditions:

      1. The LSR that sent the label mapping is no longer the next hop
         for the mapped FEC, and the LSR is configured for conservative
         operation.

      2. The LSR receives a label mapping from an LSR that is not the
         next hop for the FEC, and the LSR is configured for
         conservative operation.

    *  3. The LSR receives a Label Withdraw message.*

With Regards
Anil S N