Subject: Label mapping from targetted peer

From: "Vijayanand C" <[email-masked]>
Date: Thu, 31 May 2001 10:52:20 +0530

Hello all,
I have a question regarding the label mapping procedure(A.1.2) of
rfc3036(LDP).

In Lmp.11,12,13 the next Hop for FEC is checked and if message source is not
the next hop, the label release procedure is executed.

Suppose the peer which sent the label mapping is a targetted peer, then it
will not be the next hop for the FEC but still, it may be a valid mapping if
the mapping has come through the correct next hop interface. So, I think the
check should do more than just compare the message source against the FEC
Next Hop.Going one step further, what to do if there are 2 or more targetted
peers on the same Next Hop interface for the FEC and both of them send
Unsolicited label mappings. How will we decide which to retain and which to
drop?

Please correct me if I am wrong.

Regards,
Vijay

---

From: Eric Gray <[email-masked]>
Date: Thu, 31 May 2001 16:42:24 -0400

Vijay,

    Consider two cases: one, the targetted LSR _is_ a next hop on
some (one or more) LSP(s) corresponding to a link/interface(s) at
the local LSR; two, the targetted LSR _is_not_ a next hop in any
sense.  In the former case, LMp.12 takes you past LMp.13 and the
local LSR can use these labels when sending packets to the
targetted LSR over an LSP that acts as a direct link.  In the latter
case, the received label is not useful, anyway, and would naturally
be released.

    If an LSR receives a label from another LSR that is not directly
connected to it - by some definition of 'directly connected' - then
I cannot use the label because no directly connected LSR will be
able to interpret it.

--
Eric Gray