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