RE: Why wrong LINE rate could cost dear
- To: "Perkins, Drew" <drew.perkins@xxxxxxxxxxxx>, <stds-802-3-hssg-speed@xxxxxxxx>
- Subject: RE: Why wrong LINE rate could cost dear
- From: Fred Weniger <weniger@xxxxxxxxxxx>
- Date: Tue, 29 Jun 1999 20:51:11 -0700
- In-Reply-To: <2072E1221F1DD211848C00104B938E7B733591@xxxxxxxxxxxx>
- Sender: owner-stds-802-3-hssg-speed@xxxxxxxxxxxxxxxxxx
I agree with your position, especially your concluding statement. Also, if
you allow the GaAs Industry the opportunity to compete with other
technologies in the same space (specification-wise), you will find we are
very cost-effective. We need to hear more from the optics vendors on this
topic, and I suspect we will!
At 08:47 PM 6/28/99 -0700, Perkins, Drew wrote:
>It seems to me that we're drawing to a conclusion something like the
>Semiconductor technology is continuing to follow Moore's Law. That suggests
>that the next generation of silicon will support something in the
>neighborhood of 2.5 - 3.125 Gb/s since the current generation supports 1.25
>Gb/s. Some day, however, another generation (maybe the next) will support
>something in the neighborhood of 10 Gb/s. This may be using SiGe instead of
>Si. So, we should plan for two or more generations to occur: 2.5 - 3.125
>(G1) and 10 Gb/s (G2). Of course GaAs supports 10 Gb/s today, but is seen as
>being more expensive than Si or SiGe. So we probably want to specify a
>serial version of 10 Gb/s immediately as well, but we should expect that we
>may have to revise it when G2 becomes available.
>G1: For Generation 1, we will want to use a non-serial protocol
>implementation that leverages G1 silicon. This may be WWDM/CWDM/etc. and/or
>MAS. We may also need to do this because of fiber impairments that don't
>allow 10 Gb/s serial anyway. For G1, we may want to specify multiple
>standards, just like Gigabit Ethernet did. We may want equivalents of SX and
>LX. In fact, perhaps these two standards were well enough matched to market
>demands that we should copy the requirements and try to meet them. Also,
>these standards may have not set a good set of expectations that the market
>will force us to meet. I would propose that we take these two as baseline
>goals. I.e. let's use the same fiber types and lengths as our goals and try
>to work with them. This probably implies that we want an SX-like solution
>that uses 850 nm VCSELs, and an LX-like solution that uses 1310 nm FP
>G2: For Generation 2, we will want to use a serial protocol implementation
>that leverages G2 semiconductors on fiber that supports it. In fact, we
>probably want to specify and standardize a 10 Gb/s solution immediately as
>well for use with GaAs technology.
>Ciena Corporation Email: ddp@xxxxxxxxxxxx
>Core Switching Division Tel: 408-865-6202
>10201 Bubb Road Fax: 408-865-6291
>Cupertino, CA 95014 Cell/Pager: 408-829-8298
>[mailto:owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx]On Behalf Of
>Sent: Monday, June 28, 1999 5:46 PM
>To: piers_dawe@xxxxxx; stds-802-3-hssg-speed@xxxxxxxx;
>Subject: Re: Why wrong LINE rate could cost dear
>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.
Product Marketing Manager, Gigabit Products
Vitesse Semiconductor Corporation
741 Calle Plano, Camarillo, CA 93012
Phone: 805-388-7571 Fax: 805-987-5896