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Title: RE: MPLSOAM BOF meeting draft minutes Hi
Dave:
I
understand your points.....
When
it comes to fault management (which this discussion seems to be focused upon),
my expectation is that I'm doing this for multiple reasons, first is knowing I
have a problem, the second is the possiblity of the network taking some
automated corrective action, protection switching, local repair, re-route etc.
So I have a reasonable expectation that the layer/level doing fault management
also has the ability to take some corrective action.
If I'm
doing fault management at the pseudo-wire layer, I have trouble imagining it's
utility. It will either depend on the lower layer to take some corrective action
(wait some arbitrary amount of time before declaring the service dead) or it
will have to implement some nodal behavior to direct the lower layer to take
some corrective action. This could get messy.
If the
fault actually occurs in the PW end points, then if the transported service has
it's own OAM (e.g. ATM, SONET or FR), then I am assuming that the interworking
function (IWF) would permit the fault to be sectionalized as either the PW or
the ingress/egress links. Its only if the PW interworking function is
transparent to the higher layer OAM that you lose this capability, the PW and
the ingress/egress appear as a single link.
Similarly if either end of the PW goes down or
degrades, the service is effectively toast unless the PW client layer has some
degree of agility and can detect the fault and take corrective action.
So
IMHO fault management is required in layers that can proactively respond to
faults. I understand that there can be a rationale for a pseudo-wire having
some OAM functions, but this does not eliminate the need for OAM in the PW
transport, in this case MPLS.
rgds
Dave
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