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Re: [10GMMF] Customer Issues with LRM


I understand your point that the 300m is customer driven. However, I believe that the reality is that for 62.5 um fiber the 220m might be the best you can get. As you  want, I would also like to see this standard succeed, but measurements, as well as simulations on legacy fibers paint different picture and raise doubts that 300m can be achieved.

I guess that some people (especially on the electronic hardware side) will say that 300m is achievable, and some (mostly optical module manufacturers) will be hesitant on the higher distance. At the end, what distance the standard adopts will be based on the people's opinion regarding the distribution of installed fibers and the risk they are willing to take: if they view the current set of fibers (both as hardware and as software models) on which we do experiments and simulations as conservative, 300m will be acceptable, and wise versa: if they think that the fiber set is realistic or optimistic, they will support the shorter distance.

Again, I would like to see 300m standardized, but have some doubts.



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

Bruce Tolley <btolley@CISCO.COM>
Sent by: owner-stds-802-3-10gmmf@IEEE.ORG

11/05/2004 01:30 PM
Please respond to
"IEEE P802.3aq 10GBASE-LRM"

[10GMMF] Customer Issues with LRM

>Dear Colleagues:

My job has changed a bit at Cisco and now I am focused more on booking
revenues on a daily and monthly basis so I doubt I shall be able to attend
the Plenary.

I would like to sum up my perspective on customer requirements for LRM for
the project to consider if we really hope to deliver a successful
technology to the market. The data is based on 1) I am a customer and 2)
interaction with my customers.

The clear requirement is for LRM to reach 300 meters. Anything less at this
point is a non starter. The bar is not 220 meters with 1000BASE-SX on MMF
but the fact that 10GBASE-SR and 10GBASE-LX4 are shipping and both reach
300 meters. Customers have the clear requirement to go 300 meters on MMF
both installed and the new OM3 fiber.  This is reality today.

Offset launches
Customers (my customers) and me (a customer) need one LRM solution for 50
and 62.5 micron fiber.  I am not convinced that one offset launch condition
will be optimal for both 62.5 and 50 micron fiber.  I and my customers
would rather deal with the complexity of a dedicated MCP than with two
different products with different built in offsets. Based on engineering
experience with a related project, I am also not convinced that an internal
offset will offer any cost savings on the module cost over the cost of a
module plus MCP.



Bruce Tolley
Product Line Manager
Transceiver Module Group
Gigabit Systems Business Unit
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134-1706
ip phone: 408-526-4534