RE: Moving right along ... generalized-rsvp-te-05

[neil.2.harrison@bt.com]

Hello Ben......you asked a specific question 11 December 2001 14:38
<snipped> 
> > >7) The Notify message is intended to "enable expedited 
> notification of
> > >    failures," but it relies on the IP layer which may be 
> affected by the
> > >    failure that the Notify is reporting.  This could 
> defeat the goal
> > >    of rapid notification.  Without some means of 
> guaranteeing the Notify
> > >    doesn't have to wait for IP routing convergence to be 
> delivered,
> > >    it isn't a satisfactory solution.
> > >
> 
> Well?  Does anyone else have thoughts on this?
NH=> Yes, but these are not 'thoughts', this is what is required and indeed
provided on all transport networks defined by the ITU:

There must be a user-plane Forward Defect Indication (FDI) provided.  The
key reason this is required is to suppress downstream alarms......and this
includes *all* client layer network trails supported above the trail source
of the orginal defect.  Which therefore implies it must have a
server->client FDI mapping specified at the relevant adaptation points, and
note that this requirements recurses through all the layer networks
affected.  This requirement becomes increasingly important for international
(and larger than 1 management domain) trail spans....which, noting the
previous comments, may not be directly obvious to the source layer of
failure, ie in different country/operator/customer domains.

This is a well-known transport network requirement that simply has to be
provided, and I thought everyone knew this?
Note - it will not be satisfactory to assume that this function can be
provided via the control-plane (using any of the protocols supported) or
indeed via the (user-plane) OAM of any other layer network.  The reasons why
are obvious (I hope).

regards, Neil