Re: [CCAMP] A general question on the WSON Framework draft

[Lou Berger <lberger at labn.net>]

Young,
	Please see below for in-line responses.

On 10/20/2009 7:14 PM, Young Lee wrote:
> Hi Lou, 
> 
> Thanks for your comments. Please see in-line for my response. 
> 
> In a nutshell, what the authors' intention of the WSON Framework was to stay
> in the basic RWA issues (including Wavelength Converters and OXC); 

doesn't really leave much out ;-)

> 
> Having said that, any multi-signal related issues (we refer to this as
> signal compatibility and processing constraints) that encompass Regenerators
> and OEO switches is addressed in a separate document we just updated. 
> 

see below.

> Impairment has been addressed separately as you know. 
> 

Right.  This fits with point of a function being allowed for in the
framework, but not being fully defined.

> Perhaps, Greg can elaborate more from his perspective.
> 
> Regards,
> Young
> 
> -----Original Message-----
> From: Lou Berger [mailto:lberger at labn.net] 
> Sent: Tuesday, October 20, 2009 5:03 PM
> To: draft-ietf-ccamp-rwa-wson-framework at tools.ietf.org
> Cc: CCAMP WG
> Subject: A general question on the WSON Framework draft
> 
> Authors, (WG)
> 
> 	I have a pretty basic question on the WSON framework document:  What
> is
> the scope of the optical networks covered by this framework?
> 
> I think the document should be very clear on this.
> 
> Keep in mind that a framework (or even protocol) may allow for, i.e.,
> not preclude, functions and aspects of an architecture or solution
> without fully defining them.
> 
> To elaborate on my question:
> 
> A) It's clear that some portions of optical networks are in scope, such
> as: "wavelength division multiplexed links, tunable laser transmitters,
> reconfigurable optical add/drop multiplexers (ROADM) and wavelength
> converters". But it is unclear if other portions are in or out; in
> particular regenerators, OEO switches and, to some degree, OXCs.  All
> are mentioned in the document, but the document is a bit vague on
> whether they are part of the framework or not.  So what's included and
> what's excluded?
> 
> YOUNG>> WSON RWA Framework includes wavelength division multiplexed links,
> tunable laser transmitters, reconfigurable optical add/drop multiplexers
> (ROADM) and wavelength converters and OXC. 
> 
> Regenerators and OEO switches are addressed in the context of signal
> compatibility in a separate document. 
> 
> My personal opinion is that the framework should allow for all aspects
> of today's optical networks, but need not define support for each (e.g.,
> impairment based RWA).
> 
> YOUNG>> I agree. The concern we have had was the document gets larger and
> larger to the point that it is hard to read and edit. 

The flip side of this is that you can end up with such a fragmented
document set that the base set isn't really usable (at least in
practical terms), and that the base can get significantly out of sync
with a critical component.  I fear this is where we're ending up with
the current work.

> In the framework, we
> added the document relationship across RWA, Impairment and Signal
> Compatibility so that these are all included in the larger WSON scope than
> the document is addressing. 
> 

right now it reads to me as covering half the relevant problem space,
leaving out some very basic (and almost always used) functions.

> 
> B) Are multiple signal types included or not?
> 
> YOUNG>> No. 
> 
> The document seems to say that they are not, but then there is section
> 3.2.2.  It seems to me that it really doesn't take much to allow for
> support of multiple signal types in this document.  Given that multiple
> signal types are a reality in today's optical networks, I personally
> think they belong in the framework.
> 
> YOUNG>> We thought we asked the WG chairs in Stockholm meeting. What we
> thought we heard was a suggestion to separate "signal issues" from the basic
> RWA issues. 
> 

I believe we ended this part of the discussion with "let's take it to
the list".  Albeit a bit delayed, here we are ;-)

More seriously, I think there's some concern about defining
attributes/functions that are currently not standardized in the ITU-T.
I think this is a point that we need to be sensitive to, particularly
when considering solutions drafts.  But this document is a framework
document and, in my personal opinion, the framework should cover (or
allow for) all aspects of a typical optical network.

Lou

> I have a bunch of more minor comments on the document, but will hold
> these until the above is closed.
> 
> Much thanks,
> Lou
> 
> 
> 
> 
> 
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