RE: [EFM] Moving forward on extended temperature range optics
Colleagues,
Geoff brings up a good point here. In this thread the discussion has mainly been on the structure of the standard to meet the objectives of the task force. However, as he points out, there appears to be an undercurrent of concern that the present objectives (10km, extended temperature range) cannot be met in a manner consistent with two of the five criteria. Until we have concensus on this issue the structure of the standard to support this is not particularly relevant. I think that a temporary shift in emphasis is in order.
Personally, I am comfortable with the technical and economic feasibility. Looking at the published specifications of commercial parts that claim 10km and -40degC to +85degC operation I note that they are nearly within the bounds of the present specifications of Clause 59. Not much tweaking would be needed. Remember, these specifications were developed before Clause 59 was written. I feel comfortable that Clause 59 can be met. However, other may not agree. We need a larger concensus here.
I think this breaks down into two topics.
First, from link designers, do the present Clause 59 requirements satisfy 10km at 1.25Gbaud? If not, what should the requirements be?
Second, from component suppliers, can you deliver components meeting the optical requirements of Clause 59 over the Industrial Temperature range (-40degC to +85degC) without a significant price hit compared to the present 100BaseLX components? If not, how big will the impact be?
Until concensus has been reached on these items, I do not think that we can move forward. I would like to ask for comments on the two items above.
Jerry Radcliffe
-----Original Message-----
From: Geoff Thompson [mailto:gthompso@xxxxxxxxxxxxxxxxxx]
Sent: Sat 1/25/2003 2:33 AM
To: stds-802-3-efm@ieee.org
Cc: thompson@xxxxxxxx
Subject: Re: [EFM] Moving forward on extended temperature range optics
Colleagues-
After the discussions at Vancouver and all of the messages that have piled up in the past few days regarding extended temperature optics, I feel that there are a few essential words that still need to be said, explicitly.
P802.3ah was approved as a project on the basis of satisfying the 5 Criteria
Those criteria are:
* Broad Market Potential
* Compatibility with IEEE Standard 802.3
* Distinct Identity
* Technical Feasibility
* Economic Feasibility
The anecdotal discussions (not conclusive, alleging or, at least, casting suspicion) that I have heard are that the optical specs needed are not technically feasible at extended range, or at least not without significant cost impact.
At Vancouver we had rather painful discussions about having several different temperature ranges and type naming therefore, painful to the extent that people explicitly mentioned loss of distinct identity.
So what it seems to me is happening (in 802.3 terms) is...
The group is desperately trying to trying to juggle and trade off:
* Distinct Identity
* Technical Feasibility
* Economic Feasibility
without losing Broad Market Potential.
It is not a foregone conclusion at this point that we can make it on all 5 at the same time.
It seems to me that in spite of Piers' argument that temperature range is out of scope, that if we can't make Technical & Economic Feasibility without using the temperature range that it takes to meet Broad Market Potential then we don't have a project.
The Five Criteria are not just a hoop to be jumped through at PAR time. They are really the criteria needed for success. If it turns out that what we put down at PAR time turns out not to be true, then the standard will not be a success.
So my bottom line from what I hear is:
If we don't have basic extended temperature optics (I'm not talking "option" here) AND we don't make our cost points THEN we don't have Broad Market Potential and don't have a "real" project (without regard as to whether or not we have a PAR).
Therefore, I urge you to support Bruce's effort and move it to center stage.
Geoff