The next high-speed Ethernet standard starts to take shape

Source: Gazettabyte

The IEEE has begun work to develop the next-speed Ethernet standard beyond 100 Gigabit to address significant predicted growth in bandwidth demand. 

The standards body has set up the IEEE 802.3 Industry Connections Higher Speed Ethernet Consensus group, chaired by John D’Ambrosia, who previously chaired the 40 and 100 Gigabit IEEE P802.3ba Ethernet standards ratified in June 2010. "I guess I’m a glutton for punishment,” quips D'Ambrosia. 

The Higher Speed Ethernet standard could be completed by early 2017. 

The group has been set up after an extensive one-year study by the IEEE 802.3 Bandwidth Assessment Ad Hoc group investigating networking capacity growth trends in various markets. The study looked beyond core networking and data centres - the focus of the 40 and 100 Gigabit Ethernet (GbE) study work - to include high-performance computing, financial markets, Internet exchanges and the scientific community. 

One of the resulting report's conclusions (IEEE 802.3 Industry Connections Ethernet Bandwidth Assessment report) is that Terabit capacity will likely be required by 2015, growing a further tenfold by 2020. 

“By 2015 core networks on average will need ten times the bandwidth of 2010, and one hundred times [the bandwidth] by 2020,” says D’Ambrosia, who is also the chair of the IEEE 802.3 Ethernet Bandwidth Assessment Ad Hoc group, as well as chief Ethernet evangelist, CTO office at Dell. “If you look at Ethernet in 2010, it was at 100 Gigabit, so ten times 100 Gigabit in 2015 is a Terabit and a hundred times 2010 is 10 Terabit by 2020.” 

"We have got to the point where the pesky laws of physics are challenging us"

John D'Ambrosia, chair of the IEEE 802.3 Industry Connections Higher Speed Ethernet Consensus group

D'Ambrosia stresses that the Ad Hoc group's role is to talk about capacity requirements, not interface speeds. The technical details of any interface implementation will only become clear once the standardisation effort is well under way. 

A second Ethernet Bandwidth Assessment study finding is that network aggregation nodes are growing faster, and hence require greater capacity earlier, than the network's end points. 

"There is also a growing deviation between the big guys and the rest of the market," says D'Ambrosia. He has heard individuals from the largest internet content providers say they need Terabit connections by 2013, while others claim it will be 2020 before a mass market develops for such an interconnect. 

D'Ambrosia says the main findings are not necessarily surprising but there were two 'aha' moments during the study. 

One was that the core networking growth rates predicted in 2007 by the 40 and 100 Gig High-speed Study Group are still valid five years on.

The other concerned the New York Stock Exchange that had forecast that it would need to install four 100Gbps links in its data centre yet ended up using 13. "If there is any company that has a lot of money on the line and would have the best chance of nailing down their needs, I would put the New York Stock Exchange up there," says D'Ambrosia. "That tells you something about bandwidth growth and that you can still underestimate what is going to happen."

"The reality is that I can't give you any solutions right now that are attractive to do a Terabit"

What next

The IEEE standardisation work for the next speed Ethernet has not started but the completed Ethernet Bandwidth Assessment study will likely form an important input for the Industry Connections Higher Speed Ethernet Consensus group. 

The start of the standardisation work is expected in either March or July 2013 with the Study Group phase then taking a further eight months. This compares to 18 months for the IEEE 40GbE and 100GbE Study Group work (see chart above). The Task Force's work - writing the specification - is then expected to take a further two and a half years, completing the standard in early 2017 if all goes to plan.

Technology options

While stressing that the IEEE is talking about capacities and not yet interface speeds, Terabit capacity could be solved using multiple 400 Gigabit Ethernet interfaces, says D'Ambrosia.

At present there is no 400GbE project underway. However, the industry does believe that 400GbE is "doable" economically and technically. "Much of the supply base, when we are talking about Ethernet, is looking at 400 Gigabit," says D'Ambrosia.

Achieving a 1TbE interface looks much more distant. "People pushing for 1 Terabit tend to be the people looking at it from the bandwidth perspective and then looking at upgrading their networks and making multiple investments," he says. "But the reality is that I can't give you any solutions right now that are attractive to do a Terabit."

All agree that the technical challenges facing the industry to meet growing bandwidth demands are starting to mount. "We have got to the point where the pesky laws of physics are challenging us," says D'Ambrosia.

Further reading:

IEEE 802.3 Industry Connections Higher Speed Ethernet Ad Hoc