Re: GMPLS signaling documents updated per last calls

[Stephen Trowbridge <sjtrowbridge@lucent.com>]

Eric,
I understand that it took some effort to come up with the sentence to which
everyone agreed. The new information since SLC is, however, that the VT3
SONET format, which we thought was the only unique format to SONET, seems
to have no mappings and is not used. With this new information, would it
be better to have a different sentence?

Certainly there is nothing incorrect the way it is written, but it may be
more helpful to readers to know to just use the SDH labels.
Regards,
Steve

"Mannie, Eric" wrote:
> 
> Hi Stephen,
> 
> The current wording is (as it is written in the updated draft that I sent
> last week on the ccamp mailing list):
> 
> "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."
> 
> 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."
> 
> This means in practice: request an SDH signal when identical to a SONET
> signal. In that case, from the control plane point of view everything is
> SDH, i.e. the control plane is not aware of SONET at all. Of course, if an
> SDH signal is requested the SDH label is used. The distinction between SDH
> and SONET in that case being only at the connection monitoring level if I am
> right (please confirm).
> 
> This doesn't mean that the SONET signal format disappear (simply not used in
> that case), for backward compatibility we need to keep it.
> 
> 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.