400G emerges as the next logical step for Ethernet
Created November 21, 2012The optical industry loves a good debate about standards! The current generation of Ethernet standards was controversial, being the first where two standards – 40 and 100 Gigabit Ethernet – were developed simultaneously. The same debate about what the next generation of Ethernet should look like is now in full swing.
In August, the IEEE Standards Association formed the IEEE 802.3 Industry Connections Higher Speed Ethernet Consensus group to build consensus on the development of the next speed of Ethernet. The IEEE forecasts that, if current trends continue, networks will need to support capacity requirements of 1 terabit per second in 2015 and 10 terabit per second by 2020.
At a panel session titled “Beyond 100G”, which took place at Ethernet Expo 2012 in New York, the majority of participants expressed the view that Terabit Ethernet is too big a step to take and that 400GbE should be next.
400GbE looks to be achievable using an evolutionary approach – 16 lanes of 25G being an obvious possibility. This should allow 400GbE client modules to be introduced at a similar cost-per-bit to future evolved 100GbE modules. Terabit Ethernet, on the other hand, would require a more revolutionary approach, in the same way that 100G on the line side required the shift to complex modulation formats. This would demand huge industry investment, and it would probably be a long time before the modules became cost competitive.
The next step is for the IEEE 802.3 Industry Connections Higher Speed Ethernet Consensus group is to prepare a consensus presentation in support of a 400GbE-specific data rate, which they hope to complete by March 2013.
There was one dissenting voice on the panel. Ron Johnson, director of product management at Cisco Systems’ Converged Optical and Routing Business Unit, told Light Reading that setting a flexible rate on the client side (the side facing the user) would boost innovation by providing a faster time to market. The usual IEEE process takes five years to produce a standard, and avoiding the need to start the standards process from scratch every time could be beneficial.
By Pauline Rigby
See Also:
Ciena Insight’s blog: 400GbE versus Terabit Ethernet: First steps toward an answer
Light Reading: Why a 400G Standard Might Draw Complaints
IEEE press release: Industry invited to participate in new IEEE 802.3 group formed to build consensus around Ethernet’s next speed
