The MPLS WG Archive

[Manoj Dutta <manoj@ipinfusion.com>]

Hi,

In RFC 3036 section A.1.2 ,LMp.18, Note 8, it is mentioned that if
LSR is not merging, then it may have sent label mapping for LSP in
question to at most one LSR.  Lets take the following scenario :

LSR A is non merge capable and operating in DoD advertisement mode with
independent control. Now, it may receive requests from multiple LSRs say
LSR B, LSR C etc. Since, it is using independent control, it may send
mapping (different labels) to LSRs B & C immediately without waiting for
a mapping from its next hop (offcourse it will send requests to next hop
for each such mapping). Also, it may so happen that LSR B is also non
merge capable and it may send multiple requests to A (one for each of
B's upstream peers). In this case, we might end up in a situation where
A has send multiple uniquely distinct mappings to B and one (or
more) uniquely distinct  mappings to C for the same FEC. Now, when
A receives a mapping from its next hop for the FEC in question, we see
that Note 8 as enumerated above is clearly violated as there is more
than one LSR (in this case B & C) for which A has previously sent a
mapping.
Let me know if there is some inconsistency in the above mentioned line
of reasoning.

Thanks in advance
manoj