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

Re: [EFM] Clarification of Copper Objective


Because of having to spend time with the OAM track, I have not spent a lot 
of time in the copper track.  Coming from a service provider environment, I 
see two separate and distinct deployment markets for Ethernet over 
copper.  One is high bandwidth (10Mbps) support for business customers in 
multi-tenant buildings and in business parks.  There is also a backlog 
demand for low bandwidth (< 1Mbps) residential broadband connectivity 
through Ethernet over long reach copper local loop facilities.
While the business services market is large, the resident market is 
potentially MASSIVE.  Over a period of years both of these markets should 
increase their bandwidth demands, which will be a driver for facilities 
overbuild, perhaps using fiber.

Until then, short of allowing other standards bodies to take over the 
standardization of Ethernet PHYs, 802.3ah needs to recognize and have 
objectives that meet the deployment markets.  How do we make that happen?

 From what I understand, ANSI is working on copper local loop data 
transmission facilities standard that is equivalent to an Ethernet PHY.  If 
the group wants to allow ANSI and ITU to take control of Ethernet data 
transmission facilities standards, then I am fine with that.  Personally I 
hate to see that happen.

Thank you,
Roy Bynum

At 09:23 AM 6/11/2002 -0700, Howard Frazier wrote:

>We have noted with concern that there seems to be some
>confusion regarding the interpretation of the IEEE P802.3ah
>EFM Task Force copper PHY objective. Given that the objective
>is terse, and provides room for interpretation, we offer the following
>clarification.  Please parse this clarification carefully.
>The objective:
>        PHY for single pair non-loaded voice grade copper
>       distance >=750m and speed >=10Mbps full-duplex
>The interpretation:
>The 802.3ah task force has chosen an objective that specifies
>a symmetric MINIMUM bit rate at a particular link distance.
>It would be perfectly valid to build and deploy equipment that
>provides an asymmetric service at that distance, provided that
>the minimum is met in each direction.
>Similarly, it would be perfectly valid to build and deploy equipment
>that offers a different bit rate at a different link distance, provided
>that for all link distances less than the distance specified in the
>objective, the minimum bit rate is met in each direction.
>The objective does not have to be met on all possible copper
>loops of the specified length, nor does it have to be met in the
>face of all possible impairments.
>Howard Frazier
>Chair, IEEE P802.3ah EFM Task Force
>Robert Grow
>Chair, IEEE 802.3 CSMA/CD Working Group