-----Original Message-----
From: Greg Bernstein [mailto:gregb@grotto-networking.com]
Sent: Wednesday, April 15, 2009 10:02 AM
To: julien.meuric@orange-ftgroup.com
Cc: ccamp@ops.ietf.org
Subject: Re: Generalizing WSON information...
Hi Julien, interesting point. It did seem like older SDH
equipment did have a "time-slot continuity constraint", but I
never directly dealt with those systems. There was some work
a while ago on MS-SPRing (Diego?).
Maybe we need to think up a level, as you said in the usual
GMPLS, MPLS cases full label swapping is a typical
capability. Should we be explicit in the WSON case (maybe
with the connectivity matrix) in indicating that this may or
may not be the case? Right now we are being implicit about
this lack of wavelength (label) conversion capability.
The notion of the shared wavelength converter pools and the
accompanying details seem very WSON specific. But the fact
that a switch or mux can't perform label exchange seems a
fairly general notion that we could group with other
generalizable information...
Best Regards
Greg
julien.meuric@orange-ftgroup.com wrote:
Hi Greg.
Just a small comment on Wavelength Converter Pool in
section 3.2. In some other GMPLS contexts, this may be
modelled as a label swapping capability, which is a common
enough to be considered as "Generalizable" (it's even a
typical case that becomes an exception due to our label
continuity constraint). However, as for several other
parameters, I don't think there is an actual need for it
(this is already the default); but maybe we could imagine
some MS-SPRing operations in SONET/SDH.
Regards,
Julien
-----Original Message-----
From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On
Behalf Of Greg Bernstein
Sent: Tuesday, April 14, 2009 6:32 PM
To: ccamp
Subject: Generalizing WSON information...
Hello fellow CCAMPers, at the 74th IETF meeting in San
Francisco the
question came up as to what if any of the WSON path computation
information model would be useful in other technologies. Below is a
first attempt at such an assesment based on the current version of
draft-ietf-ccamp-rwa-info-02.txt.
Existing GMPLS
standard information is not included.
From section 3.2 Node Information:
Switched Connectivity Matrix: Generalizable:Yes. This can
be used to
model any type of asymetrical switch in any technology. Caveat:
Besides optical is there any current products that can make use of
this?
Fixed Connectivity Matrix: Generalizable: Yes. This can be used to
model fixed connectivity between ports. Caveat: Is there any need
outside optical?
Wavelength Converter Pool: Generally useful: No. This is very
application specific to optical switching systems.
From section 3.3 Link Information:
Switched and Fixed Port Wavelength (label) Restrictions: Generally
useful: I don't think so but open to examples. These
constraints must
be shared in the WSON case for two reasons: (a) the wavelength
continuity constraint requires global label assignment, (b) WSON
devices present many different types of wavelength
constraints. Note
that without requirement (a) then (b) doesn't need to be
shared since
local label (wavelength) assignment would suffice.
From section 3.4 Dynamic Link information
Available Wavelengths (labels): Generally useful? We need detailed
wavelength availability information due to the wavelength
continuity
constraint.
Way back
in the old days many of us implemented bit maps to track SONET/SDH
time slots but this never made it into the standards. Any
interest in
that now? Other examples?
Shared Backup Wavelengths (labels): Similar to the above
but used in
efficient shared mesh backup path computation.
From section 3.5 Dynamic Node Information
Wavelength Converter Pool Status: Not generally applicable. Too
application specific.
Comments appreciated
Greg
--
===================================================
Dr Greg Bernstein, Grotto Networking (510) 573-2237