Everything That's New About Ethernet

14 Sep 2016 • 6 minute read

IEEE 802.3 is the standard number for various flavors of Ethernet. With Ethernet constantly increasing its speed for use in data centers, Ethernet moving into vehicles, power over Ethernet, and Ethernet over various media, there is a lot of work going on. In July, there was a plenary meeting in San Diego that Cadence attended.

I realize not many of you are that interested in Ethernet standardization task forces. Me neither. But if you read over this list, you will get an idea of where Ethernet is going. You don't need to absorb the details, it's more of a stream-of-consciousness thing. For instance, did you know there is discussion of a multi-gigabit automotive Ethernet standard? That's quite a step up from CAN bus.

The big trends:

Higher data rates for datacenters
Power over Ethernet (POE) at higher power
Ethernet over different media, single twisted pair, multiple twisted pair, coax, regular (glass) optical fiber, plastic optical fiber
Ethernet moving into cars and trucks
Extended reach, up to 40km, for campus and metro access

So here is a high-level summary of what standards are in the pipe. There are a large number of them. If you want to know the technical details of any standard, there is a lot of information online. Start from http://www.ieee802.org/3/ and go from there.

802.3bn - EPON Protocol over Coax (EPOC)

EPON is an existing Ethernet standard for passive optical networks that defines a protocol for connecting a single location to multiple endpoints. The 802.3bn project has defined a mechanism to apply this protocol over co-axial cable rather than optical fibers.

802.3bp – 1000BASE-T1 Gigabit Ethernet PHY for Vehicular Ethernet

This task force has defined an automotive PHY to operate on 15m of low-cost single-twisted-pair copper cable for cars and 40m of a higher cost cable for trucks. In June, the IEEE-SA Standards Board approved draft 3.4 as IEEE Standard 802.3bp-2016.

802.3bq – 25/40GBASE-T

The objectives of the task force were to define a link segment based upon copper media with 4-pair balanced twisted-pair copper cabling, up to two connectors, up to a minimum of 30m, and to define a 40Gb/s PHY supporting operation on the link segment and a slowed-down version supporting 25Gb/s operation. In June, the the IEEE-SA Standards Board approved draft 3.3 as IEEE Standard 802.3bq-2016.

802.3br - Interspersing Express Traffic

This task force has defined a shim layer between two MACs and a single PHY, to allow traffic from one of the MACs to interrupt traffic being sent by the other MAC. In June, the the IEEE-SA Standards Board approved draft 3.1 as IEEE Standard 802.3br-2016.

802.3bs – 200G and 400G Ethernet

This task force is defining the standard with MAC rates of 200Gb/s and 400Gb/s, with BER better than 10^-13.

802.3bt - DTE Power via MDI over 4-Pair

This task force has the objective to almost double the amount of power that can be supplied over four twisted pairs from 25W to 49W. The standard is messy because it defines multiple ways of doing the same thing to support legacy implementations. The main technical problem is understanding the properties of current cabling installations and how they generate and dissipate heat under high current loads.

802.3bu - 1-Pair Power over Data Lines (PoDL)

The intent is to be able to deliver power and wake-up functionality over the cables (single twisted pair) that will be used with 802.3bp/802.3bw automotive PHYs.

802.3bv - Gigabit Ethernet over Plastic Optical Fibre (POF) Task Force (1000BASE-RH)

This study group has the objective of 1 gigabit full-duplex operation for the automotive environment, with operation over at least 15m of POF with 4 in-line connectors, or 40m of POF with no in-line connectors (for automotive), and BER better than 10^-12.

802.3bw - 1 Twisted-Pair 100Mb/s Ethernet Study Group (100BASE-T1)

This project standardized the OPEN Alliance BroadR-Reach (OABR) PHY as an open 802.3 standard. The project is now complete and IEEE Std 802.3bw-2015 100BASE-T1 has been published.

802.3by - 25Gb/s Ethernet on a Single Lane

For cost reasons, single-lane 25G is seen as the next speed jump for compute servers after 10G. It can reuse the 25G electrical interfaces developed by the 802.3bj and 802.3bm projects. Goals: BER of better than or equal to 10^-12 at the MAC/PLS service interface (or the frame loss ratio equivalent). Support optional Energy Efficient Ethernet operation. Define a single-lane 25Gb/s PHY for operation over a PCB backplane. Define a single-lane 25Gb/s PHY for operation over links consistent with copper twin axial cables, with lengths up to at least 3m. Define a single-lane 25Gb/s PHY for operation over links consistent with copper twin axial cables, with lengths up to at least 5m.

802.3bz - 2.5/5GBASE-T

Support MAC data rates of 2.5Gb/s and 5Gb/s. Support a BER better than or equal to 10^-12 at the MAC/PLS service interface (or the frame loss ratio equivalent). Define a 2.5Gb/s PHY for operation over up to at least 100m on four-pair Class D (Cat5e) balanced copper cabling. Define a 5Gb/s PHY for operation over up to at least 100m on four-pair Class E (Cat6) balanced copper cabling. Data rates higher than 1G are needed to support next-generation wireless access points over existing cable infrastructure. Final approval of the standard is likely in August 2016.

802.3ca - Physical Layer Specifications and Management Parameters for 25Gb/s, 50Gb/s, and 100Gb/s Passive Optical Networks (Next-Generation EPON)

Goal is to support subscriber access networks using point to multipoint topologies on optical fibre. Detailed goal is to provide specifications for physical layers operating over a single SMF strand and supporting symmetric and/or asymmetric the MAC data rates of: at 25Gb/s, 50Gb/s, and 100Gb/s.

802.3cb - 2.5Gb/s and 5Gb/s Backplane

The target market is for connectivity to hard disk drives (HDD). There may be other applications that could make use of this technology such as other computer peripherals. The idea of the project is to run Ethernet over existing SATA channels. Cost is really important and 10G SerDes are considered too expensive. HDDs only require a maximum of 5G for the foreseeable future. 5G is too slow for flash drives but HDDs are expected to remain cheaper than flash drives. Using Ethernet on disk drives allows CPUs to be embedded in the drive allowing for new file systems to be implemented in software.

802.3cc - 25Gb/s Ethernet over Single-Mode Fiber

There are already standards for 25Gb/s for backplane, twinax copper, 25GBASE-T twisted-pair copper and MMF PHYs. This addresses reaches from 100m to 40km and so serves the needs of the enterprise, campus, and metro network access markets.

802.3cd - 50Gb/s, 100Gb/s, and 200Gb/s Ethernet

This project introduces 50Gb/s and 200Gb/s MAC rates and 50G, 100G, and 200G PHYs that use 50Gb/s lanes. For 50Gb/s and 100Gb/s, the BER needs to be better than 10^-12 at the MAC/PLS service interface, and for 200Gb/s, the BER needs to be better than 10^-13.

IEEE 802.3 YANG Data Model(s) Study Group

YANG is a data modeling language, describing configuration, monitoring, administration, and notification capabilities in a device-independent manner, developed by the IETF.

IEEE 802.3 Next-Generation Enterprise/Campus/Data Centre Ethernet Ad Hoc (NG-ECDC)

Chaired by John D’Ambrosia and discusses possible future Ethernet standards as an “Industry Connections Activity". Currently under discussion are future calls for interest (CFIs) for:

Single-Pair BASE-T Extended Reach – (CFI was held at this San Diego meeting)
Next-Generation Automotive – there will be a CFI for a multi-gigabit Automotive Ethernet PHY in November 2016
Extended-Reach 400GbE Optics PMDs

More information on 802.3 projects can be viewed at http://www.ieee802.org/3/.

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