Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: XAUI, SFF connectors


Where are you getting information like "13 inch copper etch radius"
from? What does that have to do with either XAUI or SFF?

I believe that you are aware that XAUI will be specified in the P802.3ae
draft to support 20" traces of common FR-4 PCB. In actual
implementations using simple transmit pre-emphasis techniques, more
complex receive equalization and more sophisticated commonly available
PCB materials, XAUI will be able to support PCB traces of a meter or

The only possibly remote connection between XAUI and SFF that I can
think of is that XAUI is capable of providing an interface to SFF
optical and copper transceiver modules of the lowest pin density of any
proposed interface. This combination of low pin count and long trace
length support from an SFF transceiver module to the protocol device
(e.g. MAC, etc.) make XAUI the only reasonable interface on the way to
an SFF connector. Do you have any suggestions for interfaces which can
meet or exceed XAUI's capabilities?

I believe that you'll see some extremely dense 10G PHY solutions very
soon which employ both XAUI and SFF connectors. XAUI is actually a
perfect match for SFF for 10 GbE. 

I'd like to hear your idea of solutions for dense 10 GbE interfaces.

Best Regards,

Roy Bynum wrote:
> 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?  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.
> 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
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