Dear All,
Here's an update on what we are doing at the GMRT, for CX4 to SFP+
conversion adaptor :
The adapter module will need a PHY chip to convert the four lane 3.125
Gbps CX4 to a single 10Gbps SFP+ output. Currently, we have selected the
Vitesse Quad PHY chip VSC 8484 for the same. The output of this PHY chip
is provided to SFP+ connector-cage arrangement, which can support either
optical or copper cable solution (active or passive). The adapter module
would require power supply ICs and EEPROM for the PHY. Mechanically, we
are trying to see if this adapter PCB can be accommodated within the space
available near the rear panel of the ROACH board. We are looking into
finer details of the mechanical and electrical aspects of the design.
Current plan is to power this adapter module using the spare ATX connector
available on the ROACH.
We are working with MTE Company (Rakesh Mehta). An NDA has been signed
for getting the details of the Vitesse PHY Chip (and also initial
samples!) -- once we have that (next few days, hopefully), the design of
the PCB will go ahead.
Comments, suggestions are welcome.
--Yashwant.
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Yashwant Gupta | Phone : +91-20-25719242 (Pune)
National Centre for Radio Astrophysics | +91-2132-252119/258316
(GMRT)
Tata Institute of Fundamental Research | Fax : +91-20-25692149/25697257
Pune University Campus, Pune 411 007 | e-mail : [email protected]
India. | [email protected]
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On Fri, 28 Jan 2011, Tom Downes wrote:
I am avoiding Myricom for the reasons Rick mentioned. It took a long
time for me to get the sales/technical person to even understand that I
wanted to go from CX4 to fiber. But Chelsio, as several
have mentioned on this list, provides the power necessary for
transceivers to work. They also have offloading cards (which I believe
is what you're describing) - or at least they did until the discontinued
their CX4 line. Not sure what the new Chelsio product line will look
like and I am somewhat dubious that they will stay on the 4-6 week
timeframe. Every vendor that I and a collaborator have called are out of
Chelsio CX4 stock. Intel makes 10gbe cards, but the list archives are
ambiguous as to whether they power the transceivers in the Zarlink
cables.
My primary concern is that if companies already see fit to discontinue
CX4 products, then (a) it is hard to connect to the ROACH now and (b)
will be nearly impossible when something breaks in 6 years.
How far along are the GMRT folks?
Tom
On Fri, Jan 28, 2011 at 6:06 PM, rick raffanti <[email protected]> wrote:
The Myricom people told me they don't make NICs with active ports- ie,
aux power for the fiber translator.
That's why we bought the Chelsio. Anton is getting 6Gb/s throughput with
the Chelsio- we haven't tried to
push it further. I wasn't aware of the UDP packet handling stuff, though.
Rick
On 1/28/2011 5:53 PM, Dan Werthimer wrote:
hi tom,
one more note:
if you use fiber optic CX4 cables,
please see the warning at
http://casper.berkeley.edu/wiki/Recommended_10_GbE_Hardware
not all NIC boards have built in power to support
fiber optic cables. check with myricom.
the ibob/bee2/roach boards have built in power.
dan
On 1/28/2011 2:41 PM, Tom Downes wrote:
So Chelsio has end-of-lifed their CX4 line. They say "4-6 weeks"
until new cards come out as
part of a new product line, but their sales contact said this
reflected a larger recognition
that CX4 is not how the industry is going.
My thought is that I should be buying an SFP+ card and figuring out a way to
convert to CX4, e.g.
SFP+->optical, optical->CX4. Our cable lengths that we will (eventually) need
are all greater than 15m,
so outside of the CX4 spec, much less what the ROACH boards are apparently
cable of driving.
Is such a transceiver scheme plausible? I am having trouble finding the
appropriate parts.
Tom
On Mon, Aug 9, 2010 at 8:11 AM, Matt Dexter <[email protected]> wrote:
Yes - when pricing switches, or any sort of (sub-)system, a full
BOM must be used to make a meaningful comparison.
Matt
On Mon, 9 Aug 2010, John Ford wrote:
And don't forget that the switches that are XFP and SFP+ sometimes
(usually?) don't include the optics for each port in the switch
price.
With CX4, all you need is a cable, if you're within a few meters.
Yes - that list is years old.
Those Fujitsu and HP switches have been tested with the CASPER
hardware
and found to work as advertised.
There are lots of new products available. More announced
all the time. We are in contact with a number of vendors in
hopes of getting demo units to try in house with the CASPER
hardware before listing them as recommended for use.
Our tests will include running at full line rates all ports
continuously
as that's what our intended applications require.
Less demanding applications will have many more, and
cheaper, options for suitable switch vendor and model.
I have no prediction for when I will be able to add more
switch
models will to that list.
Matt
On Thu, 5 Aug 2010, Andrew Lutomirski wrote:
On Thu, Aug 5, 2010 at 3:21 PM, Matt Dexter
<[email protected]>
wrote:
Hi Tom,
were you aware of these ?
http://casper.berkeley.edu/wiki/Recommended_10_GbE_Hardware
Sadly the list is out of date: some of the switches are
no longer in
production. The XG700, for example, is great and cheap
but you can't
buy one without great difficulty.
I'm not sure that manufacturers really care about CX4
anymore now that
SFP+ parts are available.
--Andy
http://casper.berkeley.edu/wiki/Equipment_Cables
Matt Dexter
On Thu, 5 Aug 2010, Tom Downes wrote:
Casper-folks:
Hoping to short-circuit a fair
amount of research here in the
hope
that someone has had to do this
already. I'll soon be looking to
connect 10-20 ROACH boards by 10
gbe to a data acquisition
computer(s).
It seems like the smartest way
of doing that is getting a
16-port
switch or potentially two 8-port
switches. But the 10 Gbe port on
the
ROACH seems to be CX4 which I
take to be a less popular
connector
variety.
What kind of switches have ROACH
users out there used to connect
up a
bunch of boards? Are there
switches out there to convert
CX4 to
something with a reach longer
than the 15m Wikipedia quotes as
the
limit of CX4. 15m is very
borderline for our needs.
The prices seem to vary widely.
We do not need network admin
tools or
anything fancy. In fact our data
rates could probably go over
10Mb
cabling, but the 10Gbe interface
of the ROACH is more convenient
from
the firmware perspective. This
is more of a multiplexer than a
switch.
Tom
