Re: GMPLS signaling documents updated per last calls

[Jonathan Sadler <jonathan.sadler@tellabs.com>]

Eric -

Comments inline...

Jonathan Sadler

"Mannie, Eric" wrote:
> "A SONET signal which has an identical SDH signal SHOULD be requested using
> the same traffic parameters as for the equivalent SDH signal, and will
> consequently use the SDH label."

Why SHOULD and not MUST?  This ambiguity is likely to create
interoperability problems in the future...

> We spend with Maarten a lot of time to write that sentence (not easy to
> write).
> 
> Maybe that it should be better written:
> 
> "A SONET signal which has an identical SDH signal SHOULD be requested as an
> SDH signal using the same traffic parameters as for the equivalent SDH
> signal, and will consequently use the SDH label."

Again, "SHOULD" needs to be replaced with "MUST"...

> This doesn't mean that the SONET signal format disappear (simply not used in
> that case), for backward compatibility we need to keep it.

I'm curious what sort of backward compatability is necessary, as a
"standard" doesn't exist currently that this needs to be backward
compatible with...

> Kind regards,
> 
> Eric
> 
> -----Original Message-----
> From: Stephen Trowbridge [mailto:sjtrowbridge@lucent.com]
> Sent: Tuesday, December 18, 2001 7:46 PM
> To: Kireeti Kompella
> Cc: ccamp@ops.ietf.org; dbrungard@att.com; lberger@movaz.com;
> bwijnen@lucent.com; sob@harvard.edu
> Subject: Re: GMPLS signaling documents updated per last calls
> 
> Kireeti,
> The one outlyer is VT3 (3 Megabits). VC-3 is an extremely popular
> rate in both SONET and SDH. I exchanged an email with Deborah Brungard
> (T1X1.5 chair) on this one and I take the liberty of sharing her response:
> 
> Deborah Brungard wrote:
> > The VT3 (3M) structure was defined - but no services (mappings) were ever
> defined for it. So there are no services/equip
> > with it. My take was if in the future it was ever defined (doubtful), we
> would be adding it to g707 also. So then it
> > would just be part of g707 too.
> 
> So basically, there are no mappings or equipment functions for this rate,
> and as far as we know no network equipment or networks supporting it.
> Deborah suggests that if we were ever to define such mappings, that this
> would be proposed for addition to G.707 and hence be part of SDH.
> 
> I think our agreement had been to use the SDH label for all signals that
> had the same multiplex structure in SONET and SDH. In Salt Lake City, we
> thought
> that this was everything except VT3. Given that VT3 seems not to be a "real"
> signal at this point and will likely be added to SDH if it ever becomes
> real, does our agreement then become that we use SDH labels for everything?
> 
> Regards,
> Steve
> 
> Kireeti Kompella wrote:
> >
> > Hi Deborah,
> >
> > > I previously made the
> > > comments to merge the (1) SDH and SONET values as one value
> >
> > There was a meeting among Steve Trowbridge, Maarten Vissers,
> > Eric Mannie, Dimitri Papadimitriou, the CCAMP ADs and chairs on
> > several issues, among them this one.  The upshot was that whenever
> > possible, the SDH label should be used, with the encoding type
> > set to SDH (i.e., G.707); however, there are signals that have
> > no SDH equivalent (if I remember right, VC-3 -- someone correct
> > me!), so we will keep SONET labels and encoding types around
> > for that case and for legacy equipment.
> >
> > The revised SONET/SDH document will contain the exact wording.
> > I will also be sending a reply to the ITU communication stating
> > the agreement we came to.
> >
> > Kireeti.