Re: Why wrong LINE rate could cost dear
- To: piers_dawe@xxxxxx, stds-802-3-hssg-speed@xxxxxxxx, stds-802-3-hssg@xxxxxxxx
- Subject: Re: Why wrong LINE rate could cost dear
- From: JVpico@xxxxxxx
- Date: Mon, 28 Jun 1999 20:46:11 EDT
- Sender: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
In a message dated 6/28/99 2:41:48 PM Eastern Daylight Time,
> Why wrong LINE rate could cost dear
> 1. Cost JUMPS as bit rate goes up.
> Faster IC technologies, more heat, possibly substantial extra complexity
> around the optoelectronics.
> Lasers don't follow Moore's Law.
> Unlike transistors, there is no virtuous circle of smaller -> faster and
> cheaper -> better. The guts of a laser are sized for the wavelength.
> Laser speed has increased slowly and unevenly, but until now, they were
> fast enough (for 2.5 Gbit/s line rate). Optical modulator type
> transmitters as used in OC-192 are very expensive.
> Picking a line rate that's faster than the state of the art will delay
> product availability and cause extra costs into the future (25% to 150%
> more? make your own guess).
> 2. Standards are good.
> Line clock ICs take time and money to design. Other parts
> (multiplexers, receivers, whatever) may be in the market now for ~9.95
> Gbit/s, a very few at OC-192+FEC rates, none for 12.5 Gbit/s. Analog
> parts are rarely right first time, respins add to the delays...
> Picking a non-standard line rate could cause delay and further fragment
> the market for parts which we believe are currently too expensive but
> where volumes are driving costs down.
> So, I believe that raising the line rate of optical transmitters
> four-fold is a worthwhile achievement, and then we attach ourselves to
> the nearest standard, the OC-192 line rate of 9.95328 Gbit/s. Raising
> the line rate of optical transmitters five-fold, out ahead of the state
> of a slow-moving art and away from any standard, will cost money and
> delay and needs very good justification. There's an obvious direct hit
> on link length too (dispersion limited) but what I'm talking about is
> more severe than that.
> Can we get back the difference between what's desired and what's
> affordable by looking at line codes, interframe gap or what? Maybe
> settle for 95% of what we would like and get a good-enough job done on
> time and affordably?
> "Keep it simple, follow standards, keep it cheap."
> Piers Dawe
I heartily agree with Piers' recommendation!
As a receiver manufacturer looking for better 10g amplifier solutions,
it becomes clear very quickly that good IC's for anything above 10g
are simply not readily available, while 10g components are receiving
considerable attention from several suppliers, and are in fact providing
acceptable sensitivity performance at both 850 and 1310nm.
Although the needs for FEC will be addressed by speciality products,
this certainly will not be the main stream, and also will not reach the cost
structure necessary for a viable product on the anticipated timeline.
The most elegant, cost-effective, and especially, timely solution will
exploit those components that are already being developed for related
Common sense is a good thing.