RE: Fwd: LSC Interface Doubt ...

[Jonathan Lang <jplang@calient.net>]

Maarten,
  Please see inline.

Thanks,
Jonathan

> -----Original Message-----
> From: Maarten Vissers [mailto:mvissers@lucent.com]
> Sent: Friday, December 07, 2001 1:30 AM
> To: manoj juneja
> Cc: ccamp@ops.ietf.org
> Subject: Re: Fwd: LSC Interface Doubt ...
> 
> 
> Manoj,
> 
> Are you aware that a PXC can be operated as an ODUk switch or 
> a STM/OC-N switch in addition to an OCh switch?
> 
> The PXC is a name for an optical fabric equipment. As fabrics are typical
more
> transparent than the connected line/trib ports, those latter determine the
> switching type. E.g. a PXC connected to optical line systems including
> transponders will not operate at wavelenght level. 
A clarification here is needed.  I agree that a PXC with integrated
transponders can be TDM capable.  However, if the OLS is a separate piece of
equipment (most likely not speaking GMPLS), then from a GMPLS perspective,
the PXC is doing wavelength switching.  Granted the wavelengths actually
being switched may all be the same wavelength (e.g., 1310), but they are
still wavelength switched.

> The transponders have
> terminated the wavelengths. Such combination will switch ODUk and/or
STM/OC-N
> signals. For the case the line systems do not have transponders, the PXC
> operates as true OCh (i.e. wavelength) switch.
agreed, this is an example of 15xx wavelength switching.

> 
> Most line systems in the core network today deploy 10G wavelengths,
whereas many
> service signals are at 2G5 level. Therefore, the transponders in the line
system
> may include 4:1 TDM multiplex circuits. With future 40G wavelengths, there
will
> be 16:1 TDM mux circuits (case of 2G5 services) and 4:1 TDM mux circuits
(case
> of 10G services). Here it is more obvious that the PXC doesn't switch
"wavelengths".
I don't see the difference here (except higher rates) from the first
example.  Again,
if the PXC is speaking GMPLS, the PXC can be considered to be doing
wavelength switching since it is switching (e.g., 1310) wavelengths
transparently.

> 
> Therefore LSC for me is limited to true G.709 OCh switching; i.e. when no
> transponders are present around the fabric.
This is not the definition in GMPLS.

> 
> Regards,
> 
> Maarten
> 
> manoj juneja wrote:
> > 
> > Hi Marteen,
> >             I refer to LSC interface as defined in GMPLS architecture
> > document (i.e. interface which switch data based on the wavelength on
> > which the data is received e.g. PXC or OXC which operate at the level
> > of individual wavelength). I don't think it has any thing to do with
> > Och (G.709).
> > 
> > Regards,
> > manoj.
> > 
> > >From: Maarten Vissers <mvissers@lucent.com>
> > >To: manoj juneja <manojkumarjuneja@hotmail.com>
> > >CC: ccamp@ops.ietf.org
> > >Subject: Re: Fwd: LSC Interface Doubt ...
> > >Date: Thu, 06 Dec 2001 11:42:02 +0100
> > >
> > >Manoj,
> > >
> > >I assume you refer to G.709 OCh connections when you use the term "LSC
> > >LSP". If
> > >so, then a bi-directional OCh link connection will use the same OCh
> > >tributary
> > >slot in both directions; i.e. the same wavelenght is used for go and
return
> > >direction.
> > >
> > >Regards,
> > >
> > >Maarten
> > >
> > >manoj juneja wrote:
> > > >
> > > > Hi All,
> > > >         If I need to establish a bi-directional LSC LSP then do I
> > > > need to configure the remote end wavelengths on an LSC interface ?
> > > > Is there any case where both the upstream and downstream labels of
an
> > > > bi-directional LSC LSP be same ?
> > > >
> > > > Regards,
> > > > manoj.
> > > >
> > > > 
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