"Providing system-level support for 100 Gb/s Ethernet requires an advanced backplane design that can ensure line-rate transmission of traffic throughout the system," according to Joel Goergen, chief scientist and vice president of technology at Force10 Networks.

"The backplane is the foundation of a switching or routing system and provides the glue that interconnects all system pieces," said Goergen. "If the backplane cannot process traffic at 100 Gb/s rates, the system cannot support 100 Gb/s ports — it simply becomes the bottleneck."

According to John D'Ambrosia, scientist, components technology, at Force10 Networks, they see the demand for 100 Gb/s data rates accelerating in switching and aggregation — at data centers, at Internet exchanges and with the carriers.

The effort to create a 100 Gb/s Ethernet is under way in the IEEE802.3 Higher Speed Study Group. Efforts are also under way in the Optical Interconnected Forum to develop 100 Gb to 160 Gb electrical interfaces. Critical among these system-level requirements is the development of the backplane transmission channels that will ensure reliable very high speed communication and processing within the system.

A typical architecture is a backplane with line cards and a switch and the scenario looks like this: You have to be able to bring data from the line cards in. It travels across the backplane and is then switched — and then is sent back to another line card — and finally is sent out. Crucial to all this is the electrical transmission qualities across the backplane because it brings into play the overall properties of the controlled-impedance channels across the backplane. That's why materials such as Nelco's recently introduced 4000-13 epoxy laminates and prepregs are becoming so important because at 100 Gb/s the demands on dimensional stability and low loss are severe. And this is exactly how these materials excel.

According to D'Ambrosia, as the IEEE moves forward with its work to make 100 Gb/s Ethernet a reality, the backplane will need to be able to support multiple 100 Gb/s datastreams.

People are talking about a bonded type of approach similar to XAUI. XAUI is a concatenation of the Roman numeral X, meaning 10, and the initials of "Attachment Unit Interface." It is a standard for connecting 10 Gb devices to each other. XAUI is designed to the IEEE 802.3ae 10GbE specification and is intended as a convenient 16-pin replacement for the 74-pin, 10 Gb medium-independent interface (XGMII).

Force10 Networks is a pioneer in building and securing high-performance networks. Today, many of the world’s largest Gigabit Ethernet and 10 Gb Ethernet networks rely on Force10 Networks.

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