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Re: [HSSG] MAC Data Rate of Operation Objective


At 07:29 PM 8/14/2006 , Menachem Abraham wrote:
Geoff and proponents of "B",

1. Do you envision compatibility with telecom long haul systems as one of the objectives?
   (E.g. OC-192, OC-768, DWDM channel spacing)

Seems like it may come to pass.
Certainly it is an appropriate topic for Criteria Big Triad (BMP, EF, TF) discussions

2. IEEE 802.3 standards were successful in the market to a large extent due to their simplicity.
   Any concerns about the complexity that this approach would have?

As opposed to what?
The market for 1000BASE-T doesn't seem hindered at this point by its complexity.
It's complexity is the responsibility of the implementor and compat/conformance testers.
It's complexity in multiple laneing is masked by 4-pair media and connectors
This will be a standard for professional installation, so it can stand a little more complexity than my examples but I don't see it as a major impediment.

3. Do you envision, for example, vendor X implementing products that go up to 80G and vendor Y up to 120G and when connected to each other auto-negotiation will make them interwork?
I am concerned about the user reaction to these degrees of freedom.

These are the areas we need to study and make judgement calls as to relative and cross [BMP, EF, TF]. I have concerns but I think we can handle them in a reasonable manner. I don't think it is inherently any worse than hooking a 100 M cu port to a Gig cu port and our market should be able to handle mismatches better than our pure amateur users.


Menachem Abraham
Columbus Advisors

-----Original Message-----
From: Geoff Thompson <gthompso@xxxxxxxxxx>
Date:         Mon, 14 Aug 2006 15:53:24
Subject: Re: [HSSG] MAC Data Rate of Operation Objective

John- I count myself as an advocate of Proposal B. I do not agree that "Proposal B" is unbounded, rather that we are still very early in the process (we have not even met as a Study Group yet) and we have not yet had the "Study" of the issue of precisely what we would would be appropriate to  propose in this area. That is Study Group work! My prejudices and suspicions going into the process lie something along the following lines: * I am guessing a "PHY that binds" (PTB) similar in philosophy to the copper PHYs in EFM * I expect configurable but fixed speeds aligned to the number of lanes * Initial market relevance (and therefore initial projects) would be based on 10G lanes * I have a gut feel that we should talk in lane groups of 4 (for 10G lanes) * I would guess that 12 or 16 would be our max. * We will draw heavily on work that has been done for 10G optical PHYs but we will end up having to fiddle a bit. * I expect ribbon fiber for data centers * I expect WDM for metro and carrier Other topics will bounce in and out of our discussions. One of the most difficult will be whether or not we will depart from a strict model of [n lanes in a single point-to-point link]. There are certainly a number of places to go, e.g. * Is "n" set in the standard or configurable? * What happens when you lose a lane?         (i.e. slow down by 1/n or stop) * Do we need to take on dual homing?         (My personal opinion is that is out of scope for this project) That ought to be enough to get things kicked off. Best regards, Geoff At 02:20 PM 8/14/2006 , John DAmbrosia wrote: All, In regards to proposed MAC data rates, I have seen two basic proposals         Proposal A) 100 Gb/s         Proposal B) Scalable Solution Proposal A supports the traditional 10x increase in speed.  Proposal B, as presently discussed, is unbounded.  (The following are only my observations of statements made on the reflector by others)  The lowest limit proposed was a 4x10 approach for 40 Gb/s.  No upper limits have been proposed.  It has been suggested that this approach should use existing PMDs, but there have been also been comments regarding use of 10G, 25G, and 40G lambdas, but that carriers would want to leverage their existing DWDM layer, which mean baudrate in the 9.95-12.5 Gig.  Consuming wavelengths has been brought up as a possible concern.  It was also suggested that the greatest bandwidth demands are on VSR links < 50m and that the longer reach (>10km) may be able to live with 4x10G.  (Data in support of these observations that could be used to guide the creation of objectives would be welcome.)   An objective for Proposal A could be similar to what was done for 10 GbE Support a speed of 100.000 Gb/s at the MAC/PLS service interface.   For Proposal B, given its current unbounded nature and multiple discussion points, I am not sure what would be proposed.  I am looking to the advocates of this proposal to provide some verbiage to the reflector for discussion.  Using the objective above as a basis: Support a speed greater than 10.000 Gb/s at the MAC/PLS service interface, would create too broad an objective.   Also for both proposals what are people s thoughts on an objective that would specify an optional Media Independent Interface (MII)?   John