Hi Greg,
Sorry for the
delay in replying. I'm working on this topic since a while so yes, it's
interesting. Before going on specific issue I would have some
question/clarification regarding the draft itself.
* Within Abstract and
the following.
You don't talk about
Optical Cross Connects (OXC) is something missing or understated
somewhere?
* Section 3.1
where you state:
"A fixed mapping
between the
GMPLS label space and
these ITU-T WDM grids as proposed in [Otani] "
Does it implies a sort
of network level label space? How relate with usual local label
significance?
* Section 3.4
Wavelength Converters
"Current or envisioned
contexts for wavelength converters are : ..."
Could we think to a description/model for wavelength
converter that is technology agnostic? Simply
something like: full conversion capability, partial conversion capability
with some constrains, and may be others.
* Section 3.4. the
following:
"4. Wavelength
converters that are O-E-O based will have a restriction
based on the
modulation format and transmission speed"
Not clear to me the type
of restriction here when OEO happens... probably I'm missing what you mean
here.
* Section 4.1 when you
talk about Lightpath temporal characteristics:
"Lightpath
connection duration has typically been thought of as
approximately
three time frames: "
and the following you
define: dynamics, pseudo-static, static.
Why there?s a need of
this classification? When you us Short/long is compared to what?
minor typo on your mail below: point (c) rfc4328 (not 4238)
right?
Thanks,
Giovanni
Hi folks, I haven't seen too many comments on our draft "Framework
for GMPLS and PCE Control of Wavelength Switched Optical Networks" ( http://www.ietf.org/internet-drafts/draft-bernstein-ccamp-wavelength-switched-01.txt).
So I figured I'd point out some potentially controversial issues that the
draft brings up.
(a) The draft brings up models for the following WDM
network elements:
- WDM links
- Optical transmitters
- Wavelength Converters and OEO regenerators
- ROADMs, FOADMs, optical splitters and combiners.
For items (3) and (4) we are taking the modeling
lead rather than some other SDO. And for ROADMs, in particular, we going
beyond the classic ITU-T "fabric" model (M.3100) which has been the mainstay
of any connection oriented switch (TDM, ATM, MPLS).
(b) The draft
brings up three (not one, not two, but three) different computational models
for RWA which can impact GMPLS and PCE protocols:
- A single PCE computing both the path and wavelength
- Two distinct PCEs, where one computes the path, and a different PCE
computes the wavelength assignment
- A PCE computes the path and wavelength assignment is accomplished in a
distributed fashion via signaling (e.g., using label set objects)
Do we really need all three models?
(c)
G.709 includes the Optical Multiplex Section and Optical Channels.
RFC4238 was aimed at GMPLS extensions for G.709 (Optical Transport
Network) control. Weren't we finished with all this optical stuff years
ago?
I'd like to think the draft answers some of these questions.
I also think that network element models and the process models are important
enough to warrant this separate framework document. Your opinions are
solicited.
Regards
Greg B.
--
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Dr Greg Bernstein, Grotto Networking (510) 573-2237