This week Network World laid out some details of the work the IEEE group, the Ethernet Alliance, is doing with respect to new data rates. As mentioned in this blog post, while there are 5 shipping speeds of Ethernet (100 Mbps, 1 Gbps, 10 Gbps, 40 Gbps, and 100 Gbps), there are 5 new speeds that are currently being worked on (2.5 Gbps, 5 Gbps, 25 Gbps, 50 Gbps, and 400 Gbps). The last time Ethernet got this sexy was when promiscuous mode was introduced.
Some of the drivers for these new speeds are adoption rates of the older speeds. As detailed in the July 2014 IEEE Call for Interest , while the initial adoption for 10G, 40G, and 100G was in 2004, 2012, and 2015 (anticipated) respectively, because these speeds are turning out to be cost prohibitive, the transition to higher speeds has been slower than previously forecasted. For example, the 1G -> 10G transition has repeatedly moved out (from 2012 to 2014 to 2016 now). This creates a window where new technology can provide the higher port speed at lower cost. So, as an example, the SFP+ technology can be leveraged in 25 Gbps as a single lane and 50 Gbps as two lanes.
The 2.5 and 5 Gbps speeds (known as MGBASE-T) address the growing demands of BYOD in campus networks. Many of the newer APs nowadays ship with 802.11ac. This Wifi standard will have a second wave in 2015 whereby the uplinks (or backhauls) between the APs and the access switches will be multi-gigabit rates. The key requirement here is to be able to reuse the existing cabling infrastructure. So Cat 5e and Cat 6 would still be supported over the usual 100 meters and there would be no need to rip and replace cables.
Ethernet has come a long way since the days of the 2.94 Mbps flavor that Bob Metcalfe had invented. There is very little in common between the types of Ethernet standards we have today from the IEEE and the original specification. One thing that is common, however, is the ability to evolve according to market needs, from single-pair vehicular Ethernet to four-pair PoE and in between. More on this in another post.