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Re: Does only decimal system work for data rate specification?


I think that there are several WDM and CWDM vendors that offer interfaces for
GbE.  I have a 32/64 wavelength/channel DWDM system in my lab, over which I can
run aggregated links.

Thank you,
Roy Bynum

JR Rivers wrote:

> For informational purposes only :-)....
> 802.3ad specifies a mechanism for aggregating multiple similar speed
> ethernet links into a single "aggregate port".  Customers use this today to
> provide performance scaling when they don't want to upgrade to the next
> higher speed ethernet.  In some cases, customers use a single bundle of
> copper to transport both physical ports, and it seems that some clever
> implementer or could design a way for customers to use WDM to transport the
> parallel paths over a single fiber.
> JR
> At 09:09 AM 12/9/99 -0700, Mike Wincn wrote:
> >
> >At 09:55 AM 09-12-99 +0100, Fenghao Mu wrote:
> >>1) Why we prefer to only specify 10GE rather than suggest other
> >>reasonable data rates related to gigabit Ethernet, say  2.5/5 gigabit
> >>Ethernet?
> >
> >suppose i turn the question around -- what would be the point of having many
> >more datarate communication standards, when we already have 1, 10, 100, and
> >1000-base-whatever?  it isn't clear to me that finer granularity offers any
> >useful
> >advantage.
> >
> >>2) Why we need Hari coding to tie four individual links together instead
> >>of sending data separately?
> >
> >Hari doesn't code anything.  Hari is a proposed method of standardizing
> >PMD interconnect that uses existing line codes.  otherwise, the four serial
> >links are separate, other than for issues related to word- or byte-striping.
> >
> >>3) Does our data rate specification fit with market requirement and
> >>technology progress well?
> >
> >yes, else there would not be much interest in developing a new standard
> >for interoperable, higher-datarate systems.  you should understand that
> >no one will be compelled to use any standards-based 10GbE system,
> >other than for desire to participate in that market space.  that has been
> >true for all 802.3 stuff, since inception.
> >
> >>1. From a customer point of view, only 1GE and 10GE give less choices
> >>for one to build a good switching structure. He has to chose between two
> >>possible data rates, either 1GE or 10GE. It might be very difficult for him
> >>to upgrade his data links, in other words, 10GE is too luxurious and 1GE
> >>is insufficient for his requirement. What is his best solution?
> >
> >there is already interest in developing a higher datarate standard.  issues
> >such as feasibility, interoperability, and so on are to be resolved in the
> >standards development process.  there will always be technological
> >and dollar cost barriers to general market entry, and though the standards
> >process helps to reduce that cost it cannot be removed entirely.
> >
> >>2. Data rate evenly distributed networks are seldom met in reality, and it
> >>exists only in people's imagination. Designing a switcher fabric based on
> >>this imagination will cause a big waste of resource.
> >
> >i think you will need to define your use of "wasted resource" more carefully
> >before anyone can address this.  do you want 100% capacity, 24 x 7?  you
> >won't find it here.  define your conditions and we can proceed.
> >
> >>[...] If we could use 2.5/5/10 GE data
> >>rates, we can individually assign a data rate for a path in a network
> >>according different requirements. Multiple data rates can be very helpful
> >>for optimal I/O pad usage.
> >
> >you can do that now, at 1, 10, 100, or 1000MBaud. (aside:  i offer this for
> >the sake of completion.  does anyone know whether Starlan is still in use?)
> >
> >>3. There is no reason why we only specify 10GE, which bonds 4 individual
> >>links together. Probably there isn't any information source or sink today
> >>which has to be specified at 10Gb/s.
> >
> >if that were true, there would not be much interest in HSSG participation.
> >
> >>5. At today's technology, few devices could support 10GE within one link
> >>for a meaningful distance.
> >
> >have you ever heard of OC-192/SDH-48?  you may want to try a search
> >engine.
> >
> >> From technology point of view, there isn't any
> >>remarkable breakthrough so that we can utilize a new and cheap device
> >>to implement 10GE links.
> >
> >fast VCSELs, DMD-flattened M-M fiber, fast (linear) equalization, FEC, MAS
> >and the like all offer potentially cheap solutions for 10GbE.  you may want
> >to have a look at presentation notes at the reflector site.
> >
> >>6. In fact, we could simply extend the Gigabit Ethernet standard to
> >>2.5/5 GE specification by adapting new speed as a smooth move. If we
> >>use 8B10B encoding, the speed will be 3.125/6.25 Gb/s, respectively.
> >>Simple and efficient! Why not?
> >
> >i gather that people considered that, early on.  seems there wasn't much
> >interest.
> >--
> >jmw
> >
> >