Subject: [PWE3] questions on draft-ietf-pwe3-mpls-eth-oam-iwk-03 .

From: binny jeshan <[email-masked]>
Date: Wed, 8 Sep 2010 19:46:23 +0530

Hi all,

Few questions on draft-ietf-pwe3-mpls-eth-oam-iwk-03 .

In the below section,
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*3.2** Use of PW Status notification for MPLS PSNs*

When PWs are established using LDP, LDP status notification
signaling SHOULD be used as the default mechanism to signal AC and
PW status and defects
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*[ Binny ]:* This statement may not apply at all cases, according to what i
have observed. This shall apply to defects that arise due to a CE OAM only.
But, if MPLS OAM tools like VCCV-BFD, by default when detects a LOC on a PW
in Receive direction, sets its Diag Code to '1' and sends it to other end.
The other end (example PE2) in response to this code can understand that it
is now entering a PW defect in TX direction.
In this case, there may not be a need of mandating that LDP "SHOULD" be
used. For defect notification that originate explicitly from PSN (MPLS
Cloud) side, BFD protocols already take care of informing the other end
though its diagnostic codes.
Is there any specific reason that you make this action as "SHOULD" ?

*[ Binny ]:* Which architecture/mode of interworking does this draft
describe. Is it Single Emulated mode or Coupled mode ? I belive its the
coupled mode. Is my understanding correct?

*[ Binny ]:* If CE1 is able to relay its OAM messages through the MPLS
domain to remote CE2 (may be the level of the MEPs may be different than the
one from CE1-PE1) then interworking of the defects using the mentioned
mechanisms are necessary?

*[ Binny ]: *What happened if one of the interworked MEPs are locked for OAM
traffic? For example, a MPLS OAM mechanism can go for an ADMIN DOWN where it
will not send any OAM packets to its peer? In that scenario, should the
defects originating from CE side be ignored?

*[ Binny ]: *For VPLS cases there can be many ACs mapped to one PW, what is
the action? Should the defects reported by peer, be broadcasted to all the
ACs ? My thought is that this should not be the case? How can interworking
be done in such a condition? I think this draft should be applicable rightly
for a VPWS implementation.

I shall be glad to get your replies. Any questions i have asked that you
find unclear, please do knock.

Thanks,
Binny Jeshan.