Latest Developments in Ethernet Standards

Cadence is committed to supplying Ethernet silicon and verification IP to help its customers develop Ethernet solutions. The IEEE 802.3 Ethernet standards committee recently held an interim meeting in Indian Wells, California.

 

The location and weather were good.

 

 And I got to see a joshua tree:

 

 

I blogged about the progress being made with Ethernet standards last December. Here is an update from the January meeting:

 

This project is standardizing new four-lane 100Gbps PHYs for backplanes and twin-ax copper cable. The task force spent the meeting reviewing comments from the IEEE sponsor ballot against draft 3.0. The draft received 87.5% approval with 217 comments. All comments were resolved and draft 3.1 will be published soon. 802.3bj will complete in the summer and be published as an official standard this year.

 

This project is standardizing the 100GBASE-SR4 optical PHY for use with multi-mode fiber (four strands in each direction) and CAUI4 (four-lane chip-to-chip and chip-to-module) re-timed electrical interfaces. The task force spent the meeting reviewing comments from the 802.3 working group ballot against draft 2.0. The draft received 85.3% approval with 183 comments. Draft 2.1 will be published soon. 802.3bm will complete and be published next year.

 

This project is standardizing a gigabit PHY for use in automotive environments using a single unshielded twisted pair. The main challenge will be dealing with the harsh electro-magnetic compatibility environment. The PHY will likely use three-level pulse amplitude modulation with FEC. A baseline PHY technical proposal will likely be adopted in May 2014.

The purpose of this project is to develop a 40Gbps PHY for use with four-pair, twisted-pair copper cabling. The task force has made good progress on its channel definition and has now created a strawman PHY proposal.

The 802.3br task force held its first meeting in January and will standardize a method of pre-emption to allow time-critical traffic to be sent for closed-loop control. This project is now making fast progress with a baseline technical proposal adopted at the January meeting. The task force prefers to describe its work as “Interspersing Express Traffic” rather than “pre-emption”. The task force will define a shim layer that will go between a PHY and two MACs. No changes will be made to existing Ethernet MAC and PHY specifications.

 

This is expected to become the 802.3bs project after the March 2014 plenary meeting. It will have objectives to develop a CDAUI (400G Attachment Unit Interfaces) chip-to-chip and chip-to-module interface and optical PHYs for short and long reaches.

 

The 802.3bt task force held its first meeting in January and started discussing the various architectural options to double the amount of power that can be supplied over four twisted pairs from 25 Watts to 49 Watts.

 

The 802.3bu task force held its first meeting in January and will write a standard to deliver power and wake-up functionality over the cables (single twisted pair) that will be used for 802.3bp vehicular Ethernet. The actual power level has not yet been decided.

There will be calls for interest for 25G Ethernet and 1Gbps over plastic optical fibres (POF) at the forthcoming March plenary meeting. The reason for doing 25G Ethernet is that it will allow four-lane 100G ports to be broken out as four single lane 25G ports. 25G serial gives higher throughput than 10G serial and takes up less space than four-lane 40G. The 1G over POF would most likely be used in automotive applications. There is expected to be a red LED for short reach using automotive MOST type cabling and a green laser for longer reaches.

 

Arthur Marris