The Institute of Electrical and Electronics Engineers (IEEE) has initiated a new study group to explore 4x25-Gbps interfaces for 100 Gigabit Ethernet (100GbE) in data center and campus networks. The new interfaces, expected to replace the current 100GBase-SR10 10x10-Gbps standard in time, will enable 100GbE modules that have a higher faceplate density and lower costs.
This will require amendments to the physical layer (PHY) capabilities defined in IEEE 802.3 Ethernet standard in 2010. The study group has three main areas of investigation. First is a 4x25G multimode fiber interface that can be used to send data up to 100 m; the second is a 4x25G singlemode fiber interface focused on longer reaches within data centers and campus backbones.
The third area of interest is a 4x25G electrical interface between module and system ICs. Having such an interface will eliminate the chip that multiplexes electrical signals from 10 lanes of 10 Gbps to four lanes of 25 Gbps.
“The history of optical Ethernet standards has shown that as technology advances, the ability to reduce the number of data channels and thereby the cost, density, and power required to achieve a given speed will lead to greater market adoption,” said Dan Dove, chairman of the IEEE 802.3 Next Generation 100 Gbps Optical Ethernet study group and senior director of technology at Applied Micro. “We believe that it's time to move from a 10x10G interface to a 4x25G interface to achieve the advances the market needs to take 100G Ethernet to the next level.”
The emphasis on 4x25 Gbps would appear to put to bed any ideas the Google-inspired 10x10 MSA may have had regarding adding their specifications to the IEEE 802.3 100GbE specification family.
Analyst firm LightCounting anticipates there will be rapid adoption of 40G and then 100G uplinks following the broad uptake of 10G server connections over the next three years. Kimball Brown, vice-president and senior datacom analyst at LightCounting, said, "To achieve the kind of market success LightCounting expects for 100G, cost must come down to a level that drives users to upgrade from 40G to 100G uplinks. Further, 100G transceivers must be able to fit into the then familiar QSFP+ form factor (at least for short and long wavelength media types) that users will be comfortable with. LightCounting is happy to see that these benefits will be enabled by the Next Generation 100G study group, making its formation essential."
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