-----Original Message-----
From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On Behalf
Of Greg Bernstein
Sent: mercoledì 15 aprile 2009 19.02
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