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Re: [HSSG] HSSG Reach Ad Hoc "Rides Again"

I would only add that the number of connectors for MMF is also more than the 4 used in the loss calculation. I have been reminded of this numerous time both by people from inside IBM, as well as outside.

So, let us do it right this time.


Petar Pepeljugoski
IBM Research
P.O.Box 218 (mail)
1101 Kitchawan Road, Rte. 134 (shipping)
Yorktown Heights, NY 10598

phone: (914)-945-3761
fax:        (914)-945-4134

Mike Dudek <Mike.Dudek@JDSU.COM>

11/19/2007 04:21 PM
Please respond to
Mike Dudek <Mike.Dudek@JDSU.COM>

Re: [HSSG] HSSG Reach Ad Hoc "Rides Again"

Please note that the 2dB traditionally used for the SMF link budgets is 2dB for connector and splice losses.  I also note that the loss for MTP connectors (not Elite) is 0.5dB typical 1.0dB max per connector (compared to 0.15dB typical 0.3dB max for LC) , so using our normal worst case criterion if they are MTP there could only be 2 connectors.   The attenuation figures I have listed above are from a quick search so I’d encourage any installers or others who have better information to join this thread.

From: John DAmbrosia [mailto:jdambrosia@FORCE10LABS.COM]
Monday, November 19, 2007 11:14 AM
Re: [HSSG] HSSG Reach Ad Hoc "Rides Again"

Thanks for bringing this up.  Further information on connector loss would be useful for this call.

From: Chris Cole [mailto:chris.cole@FINISAR.COM]
Monday, November 19, 2007 12:30 PM
Re: [HSSG] HSSG Reach Ad Hoc "Rides Again"

During discussion of the 100GE SMF reach objective at the Atlanta meeting, an interesting new perspective was given on how optics are used in the data center. Specifically, it was suggested (for example by Ted Seely of Sprint) that the number of connectors used in typical connections is much higher then the 4 or 5 connectors assumed in SMF link budgets. For these applications, the availability of a 10km link budget (in the 10GBASE-LR standard) has allowed supporting this higher number of connectors over data center reaches shorter then 10km.
As part of the HSSG Reach Ad Hoc, it may be beneficial to quantify the distribution of number of connectors in links as part of the effort to quantify the distribution of link reaches. We may still choose to use 2dB as an allocation for connector loss (corresponding to 4 or 5 connectors) in SMF link budgets, but would use this additional information to determine the best reach objectives. Further, we may include informative information as part of the standard to give guidance on how long reach optics can be used for shorter reach applications requiring a large number of connectors.

From: Andy Moorwood [mailto:amoorwood@EXTREMENETWORKS.COM]
Monday, November 19, 2007 8:27 AM
[HSSG] HSSG Reach Ad Hoc "Rides Again"

At the Atlanta meeting several presentations were made in the area of requirements for, and relative cost of, reaches lower than 10km over single mode fiber.  In the spirit of promoting consensus building in the group John has asked me to organize a conference call so we can have further discussion prior to the interim meeting in January.
I will forward contact information to the reflector shortly but would ask those members interested in these issues to mark in their calendars  for a conference call at 9am to 11 am (U.S. Pacific time zone) on Thursday December 6th.
Presentations from Atlanta may be found on the study group web site, links to some of the more relevant presentations are included here for convenience.
For the December conf call it would really help the group if we could receive further contributions on :
a)       the need for a sub 10km SMF reach
b)      relative costing information  for the different reaches
As of now the agenda for the call is as follows
1.        discussion of the reach and relative costing presentations made at Atlanta
2.        discussion of any new material posted to the reflector
3.        discussion of how to resolve
Many Thanks
Andy Moorwood