Subject: Independent Control Mapping in LDP

From: [email-masked]
Date: Wed, 11 Aug 1999 19:58:34 +0800

In LDP Draft 5

3.5.7.1.1. Independent Control Mapping

   If an LSR is configured for independent control, a mapping message is
   transmitted by the LSR upon any of the following conditions:

      1. The LSR recognizes a new FEC via the forwarding table, and the
         label advertisement mode is Downstream Unsolicited
         advertisement.

      2. The LSR receives a Request message from an upstream peer for a
         FEC present in the LSR's forwarding table.

      3. The next hop for a FEC changes to another LDP peer, and loop
         detection is configured.

      4. The attributes of a mapping change.

      5. The receipt of a mapping from the downstream next hop  AND
            a) no upstream mapping has been created  OR
            b) loop detection is configured  OR
            c) the attributes of the mapping have changed.

How exactly is (4) different from (5c)? Can anybody shed light on this?

Thanks in Advance
chetan

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From: Eric Gray <[email-masked]>
Date: Wed, 11 Aug 1999 11:59:10 -0400

Chetan,

> How exactly is (4) different from (5c)? Can anybody shed light on this?

You're right, since 4 OR (5 AND 4) logically reduces to 4.

But I don't think that it is harmful to include this small
redundancy to avoid implementation logical 'parse errors'.