Re: [casper] iBOB to iBOB over 15m CX4

2008-06-13 Thread mdexter
Hi Jouko,
What do you mean by Infiniband only ?

As mentioned before we are using them at 4 lanes * 3.125 Gbps not
Infiniband's 4 * 2.5 Gbps.

Matt

 Hi Matt,

 I did some research about the fiber optic links some months ago.

 It appears that the Fujitsu things are infiniband-only, they cannot be
 connected to 10 Gbps Ethernet switches directly. Or more precicely, need
 another such device to connect to a copper port.

 I did try to convince the roach people to design a footprint for a
 mainstream fiber optic transceiver, didn't succeed. As far as I know there
 are about five 10GBE transceiver standards around, three of which have
 same signals as CX4. So it would have been a zero-cost option, just add
 some wires in the PCB.

 Cheers,
 Jouko

 Life is pretty simple: You do some stuff. Most fails. Some works. You do
 more of what works. If it works big, others quickly copy it. Then you do
 something else. The trick is to do something else.


 On Thu, 12 Jun 2008, Matt Dexter wrote:

 Hi,

 We are starting to run some tests with one of the Cognitive Radio
 group's
 Fujitsu o-microGigaCN (o-MGC) fiber optic links.  This unit is on
 loan and will need to be returned in a bit.

 This consists of:
 Part number Serial number description
 FPD-010R008-OE  01B-06160045  CX4/FO transceiver, 850nm VCSEL, 3.3V
 FPD-010R008-OE  01A-05430042  CX4/FO transceiver, 850nm VCSEL, 3.3V
 FOC-CC10004   50/125um MMF 850nm wavelength approx 50ft

 optical interface is MPO connector
 electrical interface is microGiGaCN

 http://www.fujitsu.com/us/services/edevices/components/connectors/copper-modules

 These units are reportedly quite expensive; maybe $1K per link
 (2*$400+200).

 Shortly I'll work on getting revised information but back in April of
 2005
 I was told:
  Bob Thornton is the sales contact for the Fujitsu modules.  His contact
  information is:
Director of Marketing
Fujitsu Components America, Inc
bthorn...@fcai.fujitsu.com
408-745-4932
www.fcai.fujitsu.com
  He will be receiving the first production modules in the next several
  weeks.  He estimates the prices to be:
module $350;
3m patch cord $90.
Lead time:  2-3 weeks.

  The attachments were provided, back in 2005, by Fujitsu.
  I haven't found them online.



 Oren is running through some tests now. Additional results will be
 distributed later.  For now
  iBob-iBob seems aok.

  Connecting to the front of the BEE2s doesn't seem safe without
  re-machining the lower edge of the BEE2 chassis' front opening. BWRC
  folks designed this lower edge to be a pinch bar of sorts to help
 hold
  the CX4 cable assemblies in place. The FO unit becomes taller sooner
  than the WLGore CX4 cable assembly for example and thus the angle into
  the BEE2's infiniband 4x connectors looks to be too steep.  We didn't
  try to force it in.

  There is no pinch bar of any type in the back of the chassis so there
  are no obstructions.  Oren is trying those out now.

  iBob- back of BEE2 OK
  back of BEE2 - back of BEE2 OK
  back of BEE2 - iBob OK

 Over the next few days we plan on testing more extensively.

 Matt

 

 Date: Fri, 2 May 2008 11:53:41 -0400 (EDT)
 From: John Ford jf...@nrao.edu
 To: Matt Dexter mdex...@berkeley.edu
 Cc: David MacMahon dav...@astro.berkeley.edu,
 casper@lists.berkeley.edu
 Subject: Re: [casper] iBOB to iBOB over 15m CX4

 On of the non-Casper BWRC groups has a box of the fiber optic cables
 Dave mentions.  We got the OK to borrow a couple to exercise them for
 a few days.  This is high priority on the to-do list.

 Note as we as allowing longer distances the fiber optic cables
 may be easier to route than the copper versions.  Shorter radius of
 curvature and smaller diameter.

 Hi Matt.  Could you post the vendor or other info on these cables?  I'm
 interested in using something similar.

 Thanks.

 John






Re: [casper] iBOB to iBOB over 15m CX4

2008-05-02 Thread John Ford
 Has anyone tried to send 10Gbe data to an iBOB over long (10-15m) CX4
 cables?
 We find that the iBOB can transmit OK but not receive - its carrier detect
 LED
 does not light up. We have no problems with 3m cables.

 Not sure if changing pre-emphasis or signal level would help as the
 problem
 appears to be on the receive side. Has anyone else tried this?

I have tried this and it definitely does not work.  In fact, I could not
transmit, either.  I shortened the cable to 1 meter, and it works
perfectly both ways!

John



 Jonathan Hargreaves

 Jodrell Bank Observatory

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