Clearing Ethernet hurdles

The IEEE 802.3ah Task Force has made significant progress towards the development of a standard by reaching consensus on critical issues for point-to-point copper and point-to-multi-point optical specifications.

The IEEE 802.3ah ‘Ethernet in the First Mile’ (EFM) Task Force has made significant progress towards the development of a standard by reaching consensus on critical issues for point-to-point copper and point-to-multi-point optical specifications at its interim meeting in Vancouver, BC on January 6.

The copper sub-task force adopted a technical proposal for the ‘long reach objective,’ which provides copper wire Ethernet specifications at local loop lengths of 2,700 metres. This sub-task force had considered two proposals, one based on G.SHDSL and another based on ADSL+.

It chose G.SHDSL, which had strong support from service providers. In making this choice, and another one for the selection of an encapsulation mechanism for the PHY, the copper sub-task force will be able to keep pace with the efforts of the other three sub-task groups in the IEEE P802.3ah effort.

The optical sub-task force also adopted specifications for point-to-multipoint (or Ethernet passive optical networks, EPON) optical transceivers, so first-mile components can be manufactured at a lower cost than those made in accord with alternative APON (asynchronous transfer mode passive optical network) technology.

The decisions have allowed an updated draft of the IEEE P802.3ah document to be circulated for review to the members of the Task Force.

The IEEE P802.3ah EFM draft standard encompasses key technical elements needed to deploy broadband Ethernet services to business and residential users. The goal is to provide a range of benefits over traditional first mile technologies concerning cost, network simplicity, packet-based efficiency, bandwidth, scaling and provisioning.

The draft standard supports three subscriber access network topologies and physical layers: point-to-point copper over the installed copper plant; point-to-point optical fibre; and point-to-multipoint fibre.

The standard will also define common EFM operations, administration and maintenance procedures and practices.