RE: XAUI, SFF connectors
Chris,
Well, I'm sure we all have our own recollections of history which are
sure to vary, but mine is that it was driven by system vendors (PC board
vendors to me means the people who sell you raw FR4 rather than board
level end product) whose primary goal was to increase the reach of
the interface between the chips. Reducing the complexity of the
PC board traces was a secondary benefit. IC vendors and system
vendors also appreciated the reduction of the number of leads
on chips enabling support for more ports on a single chip.
So, it was system and chip vendors getting together to develop
an interface with extended distance and lower pin count.
Those of us developing Infiniband interfaces also intend to use
it to drive short (~6 m) cable connections between devices.
The Infiniband interface definition is different from XAUI.
Partly, this stems from the object to use a HARI based
interface as an electrical PMD. Partly it comes from Infiniband
supporting a range of link widths. And partly, from some differences of
technical philosophy between Ethernet and Infiniband developers
has made the Infiniband.
Pat
-----Original Message-----
From: Chris Simoneaux [mailto:csimoneaux@xxxxxxxxxxxxx]
Sent: Monday, July 31, 2000 8:18 AM
To: stds-802-3-hssg@xxxxxxxx
Subject: RE: XAUI, SFF connectors
Maybe someone can help me understand this....
Was XAUI initially driven by:
a. IC vendors as an effort to reduce the number of leads on the
chips?
b. PC board vendors to reduce the number, and complexity of traces
on a board
c. OEMs for the reasons a. and/or b.
d. Other?
Thanks,
Chris
-----Original Message-----
From: Joel Goergen [mailto:joel@xxxxxxxxxxxxxxxxxxx]
Sent: Friday, July 28, 2000 9:26 AM
To: stds-802-3-hssg@xxxxxxxx
Subject: Re: XAUI, SFF connectors
Sabato,
I agree with your comments stated below. Though I still don't believe 8b10b
was
the best choice for XUAI, I strongly believe XUAI is necessary and I support
it
completly. Thanks for taking the time to get the points across.
Take care
Joel
-----------------
"Simon L. Sabato" wrote:
> Roy,
>
> I'm quite happy to have go through the "growing pains". If this means
> beating FC and IB to 10G rates, that means that some of their applications
> will migrate to Ethernet. As they climb on the XAUI bandwagon, it will
only
> serve to increase the market for many of the components (retimers, etc)
that
> go into 10G Ethernet boxes, as well as increasing the amount of expertise
in
> the core technologies.
>
> Imagine a world where there's a limited number of experts who can put
> together a high speed interface such as XAUI (this shouldn't be very
hard...
> just look around you). Now, imagine two possible scenarios. The first in
> which 10GE, FC, and IB all have different physical layers, and the limited
> number of experts is split up into three groups. The second in which all
> have very similar physical layers and the limited number of experts work
on
> parts that could be used in each application. Now, you tell me, which one
> of the above scenarios gives the end customer the lowest cost, highest
> quality product?
>
> You seem to assume that if FC and IB reuse our technology then we are
> "paying for this and the other technologies are the actual beneficaries".
> You're partially right, we are paying for the development -- that's the
> price of being on the cutting edge. Trailing technologies will always
> leverage the latest technology.
>
> But your continuous assertions imply that we are paying for development of
> XAUI features that *are not useful in 10GE*. These assertions need to
stop
> or backed up with some information that makes sense. I have yet to see
this
> information. I've seen a lot of explanations from varied people at
various
> companies explaining the benefits of XAUI. I find it odd that you can be
so
> sure that *no-one* needs something. It's easy to know what *you* need,
but
> how can you speak for everyone else?
>
> In summary, I see XAUI as a way to use a common technology across various
> applications due to the shared market and shared expertise. Using TTL
> voltage levels across various applications is a *good thing* even if, say,
> it wasn't particularly ideal for each one. The only argument against this
> is that we are saddling XAUI with burdens from other standards, which you
> claim but cannot substantiate.
>
> -Simon Sabato
> -Manager, Product Architecture
> -InterNetworking Operation, Intel Corp.
>
> P.S. Speaking of what is "costing" the 10GE group, constant discussion on
> subjects that are closed costs us all. It just cost me twenty minutes to
> write this message, and a whole lot to read all the others.
>
> > -----Original Message-----
> > From: owner-stds-802-3-hssg@xxxxxxxx
> > [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Roy Bynum
> > Sent: Thursday, July 27, 2000 2:55 PM
> > To: stds-802-3-hssg@xxxxxxxx
> > Subject: Re: XAUI, SFF connectors
> >
> >
> >
> > Ali,
> >
> > You may have it backwards. XAUI is not presented as a back plane
> > technology. XAUI is presented as a copper etch extension
> > contained only on
> > the PCB.
> >
> > The people that would be benefiting from the technology sharing is Fibre
> > Channel and Infiniband. At present, those groups do not have any mature
> > technology at 10Gb. Have you not noticed the reflector traffic
> > discussing
> > how this technology should be developed. If Fibre Channel and Infiniband
> > had demonstrated 10Gb parallel interfaces already, then it would be a
> > different situation. The original presentations on "Hari" and
> > then "XAUI"
> > would have been very different; they would have referenced previous
> > implementations. If it were mature technology from the other
> > environments,
> > then the questions of "striping" and "jitter" would have been answered
> > already and not be topics of discussion here. The fact that these are
> > topics of discussion is another proof that it is P802.3ae that is paying
> > for this and the other technologies are the actual beneficiaries.
> >
> > It will be P802.3ae that will be paying for the technology
> > development and
> > go through the "growing pains" to mature the technology. As a
> > customer, I
> > find paying for the development of a technology specific for
> > other markets
> > to be difficult to accept in order to get the technology that I
> > do want and
> > am willing to pay for. I also find it uncomfortable and insecure to
> > attempt to depend on a technology that does not have a development and
> > maturation history.
> >
> > Thank you,
> > Roy Bynum
> >
> > At 09:03 AM 7/26/00 -0700, ghiasi wrote:
> >
> > >Hi Roy
> > >
> > > > X-Sender: rabynum@xxxxxxxxxxxxxxxxxx
> > > > Date: Mon, 24 Jul 2000 14:26:27 -0500
> > > > To: ghiasi <Ali.Ghiasi@xxxxxxxxxxx>
> > > > From: Roy Bynum <rabynum@xxxxxxxxxxxxxx>
> > > > Subject: Re: XAUI, SFF connectors
> > > > Mime-Version: 1.0
> > > >
> > > > Ali,
> > > >
> > > > I agree, it should be possible to put more than one 10GbE
> > port on a PCI
> > > > form factor. I agree, XAUI is a good technology to get from
> > the backplane
> > > > to the ASIC.
> > >
> > >How do you expect 10Gig Ethernet data is getting from ASIC through
> > >backplane and to the I/O?
> > >
> > > >What I object to is hijacking the Ethernet standard to
> > > > develop technology that is not for Ethernet, but for generic system
> > > vendors
> > > > using Infeneband and Fibre Channel.
> > >
> > >Gigabit Ethernet physical layer was based on Fiber Channel, it is
called
> > >leveraging or cost amortization. Also Infeneband is written as
> > >"Infiniband".
> > >
> > > >If possible, I am going to make the
> > > > XAUI people pay for their pushing the cost of that technology
> > development
> > > > into the P802.3ae standard.
> > >
> > >Since we are going to save you some buck, I hope you don't mind instead
> > >you paying us.
> > >
> > >Thanks,
> > >
> > >Ali Ghiasi
> > >Sun Microsystems
> > >
> > > >
> > > > Thank you,
> > > > Roy Bynum
> > > >
> > > > At 10:33 AM 7/24/00 -0700, you wrote:
> > > > >Hi Roy
> > > > >
> > > > > > X-Sender: rabynum@xxxxxxxxxxxxxxxxxx
> > > > > > Date: Mon, 24 Jul 2000 11:23:15 -0500
> > > > > > To: rtaborek@xxxxxxxxxxxxx, HSSG <stds-802-3-hssg@xxxxxxxx>
> > > > > > From: Roy Bynum <rabynum@xxxxxxxxxxxxxx>
> > > > > > Subject: Re: XAUI, SFF connectors
> > > > > > Mime-Version: 1.0
> > > > > > X-Resent-To: Multiple Recipients
> > <stds-802-3-hssg@xxxxxxxxxxxxxxxxxx>
> > > > > > X-Listname: stds-802-3-hssg
> > > > > > X-Info: [Un]Subscribe requests to majordomo@xxxxxxxxxxxxxxxxxx
> > > > > > X-Moderator-Address: stds-802-3-hssg-approval@xxxxxxxxxxxxxxxxxx
> > > > > >
> > > > > >
> > > > > > Rich,
> > > > > >
> > > > > > What need does an interface card have for SFF connectors that
can
> > > only put
> > > > > > one optical port within a 13 inch copper etch radius?
> > > > >
> > > > >It should be very reasonable to put two to four 10 Gig port
> > on a PCI form
> > > > >factor card.
> > > > >
> > > > > From what you and
> > > > > > others are making us believe, the form factor
> > requirements for 10GbE
> > > > > are so
> > > > > > large that SFF connectors are a non-issue. If 10GbE
> > interfaces are
> > > going
> > > > > > to be so dense that we will need SFF connectors, why did we need
> > > XAUI? I
> > > > > > can't see how you would need both.
> > > > >
> > > > >XAUI provides high through put 3.125 Gb/s from two ASIC pin
> > (+ few extra)
> > > > >with very flexible interconnect, while keeping the package pin
count
> > > > >reasonable. XAUI is the high bandwidth pipe to get data to and
from
> > > > >your big ASIC.
> > > > >
> > > > >The other reason for XAUI was to define an interface for the
> > backplane
> > > > >and ASIC so they can be developed, while everyone is arguing on the
> > > > >right PMD for 10 gig.
> > > > >
> > > > >Thanks,
> > > > >
> > > > >Ali Ghiasi
> > > > >Sun Microsystems
> > > > >
> > > > > >
> > > > > > Thank you,
> > > > > > Roy Bynum
> > > > > >
> > > > > > At 10:13 PM 7/23/00 -0700, Rich Taborek wrote:
> > > > > >
> > > > > > >Roy,
> > > > > > >
> > > > > > >As is usually the case, you always bring up interesting
> > tangential
> > > > > > >issues in your email. This time it's:
> > > > > > >
> > > > > > >"Given the form factor that would use XAUI, SFF connectors
would
> > > not be
> > > > > > >a requirement."
> > > > > > >
> > > > > > >What in the world does the XAUI interface, specified for
> > use as an
> > > XGMII
> > > > > > >extender, have to do with SFF connectors???
> > > > > > >
> > > > > > >Please enlighten me.
> > > > > > >
> > > > > > >Best Regards,
> > > > > > >Rich
> > > > > > >
> > > > > > >--
> > > > > > >
> > > > > > >Roy Bynum wrote:
> > > > > > > >
> > > > > > > > Chris,
> > > > > > > >
> > > > > > > > I am not sure of your comment about LC having a proven track
> > > record
> > >for
> > > > > > > > single mode implementations. At present, WorldCom has not
> > > deployed
> > >any
> > > > > > > > LC. All of the connectors currently specified for SM
> > > installations is
> > > > > > > > SC. A particular vendor is attempting to get
> > WorldCom to make
> > > use of
> > > > >their
> > > > > > > > connectors. ( I will not say how successful or not they
are.
> > > > > ) Several
> > > > > > > > system vendors are attempting to make use of LC, but
> > at present,
> > > > > none have
> > > > > > > > been certified. Given the form factor that would use
> > XAUI, SFF
> > > > > connectors
> > > > > > > > would not be a requirement.
> > > > > > > >
> > > > > > > > Thank you,
> > > > > > > > Roy Bynum
> > > > > > > >
> > > > > > > > At 04:28 PM 7/21/00 -0600, Chris Simoneaux wrote:
> > > > > > > >
> > > > > > > > >Our opinion is that LC is a better connector than
> > MTRJ. The LC
> > > > > does not
> > > > > > > > >seem to suffer the possible damage that MTRJ can see
> > with high
> > > > >mate/demate
> > > > > > > > >cycles...due to the guide pin action. Also, the LC
> > has a proven
> > >track
> > > > > > > > >record for singlemode whereas the MTRJ does not.
> > > > > > > > >
> > > > > > > > >PS: My feeling is the standards body's charter should be to
> > > specify a
> > > > > > > > >connector. However, there's too much rhetoric in the
> > procedure.
> > > > > Therefore
> > > > > > > > >it's difficult to choose the best solution.
> > Inevitably the real
> > > > > winner/s
> > > > > > > > >will come forward. Conclusion: Choose a connector at
> > the standards
> > > > > > > level as
> > > > > > > > >it can expose good points of each solution.
> > > > > > > > >
> > > > > > > > >Chris Simoneaux
> > > > > > > > >Picolight
> > > > > > >
> > > > > > >-------------------------------------------------------
> > > > > > >Richard Taborek Sr. Phone: 408-845-6102
> > > > > > >Chief Technology Officer Cell: 408-832-3957
> > > > > > >nSerial Corporation Fax: 408-845-6114
> > > > > > >2500-5 Augustine Dr. mailto:rtaborek@xxxxxxxxxxx
> > > > > > >Santa Clara, CA 95054 http://www.nSerial.com
> > > > > >
> > > >
> >
> >
--
Joel Goergen
Force10 Networks
1440 McCarthy blvd
Milpitas, Ca, 95035
Email: joel@xxxxxxxxxxxxxxxxxxx
Direct: (408) 571-3694
Cell: (612) 670-5930
Fax: (408) 571-3550