GIGABIT transceiver with built-in serdes allows copper or fibre interface

Marvell of Sunnyvale, California, has developed the first fully integrated, quad-port Gigabit Ethernet transceiver to support IEEE-defined 10/100/1000BASE-T copper and 1000BASE-SX/LX fibre-optic Gigabit Ethernet interfaces in a single device.

The $125 Alaska Quad+ Gigabit Ethernet transceiver is the first quad-port device with built-in Gigabit serialiser/deserialiser (SERDES), providing flexibility in the selection of copper or fibre-optic interfaces on a per port basis. This is an important feature since many Gigabit Switches contain a subset of gigabit fibre interfaces to serve as the link to the server, the corporate backbone or even as a long-distance extension beyond the LAN.

In the fibre-optic mode, the chip is the first quad-port transceiver to incorporate the Ethernet-defined Gigabit Media Independent Interface (GMII). It also supports the latest Marvell/HP-defined Reduced Gigabit Media Independent Interface (RGMII) specification allowing for reduced system cost and design complexity. With the industry's first implementation of RGMII for fiber-optic Gigabit networks, Input/Output (I/O) pin count is reduced by more than 50%, from 25 to 12 pins per port.

The CMOS design has a power dissipation of just over 1 Watt per port for the copper connection, while in fibre-optic mode, the device consumes less than 250mW per port. This is key for building higher port count Gigabit Switches (up to 48 ports) for high-speed mixed-media data communications.

"Marvell is the `one-stop-shop' for high-density mixed-media gigabit switches,“ said Weili Dai, Marvell's Executive Vice President and General Manager of the Data Communications Group. "For example, a 24-port gigabit Ethernet switch configured with twenty-two 10/100/1000BASE-T copper ports and two 1000BASE-SX fibre ports requires the use of only six Alaska Quad+ devices to implement the physical layer. Further, with the high integration and low power consumption of the Alaska Quad+ PHY transceiver, even higher port count mixed-media gigabit switches are now possible, up to 48 ports per line card.“

But the race to ever higher speeds continue, as a 10-Gigabit Ethernet Alliance has been established by Lucent Technologies, 3Com, Cisco Systems, Extreme Networks, Intel, Nortel Networks, Sun Microsystems and World Wide Packets to drive the development of the technology.

""Lucent demonstrated the first working prototype of a pre-standard 10-Gigabit Ethernet LAN product at last year's spring NetWorld+Interop trade show in Las Vegas. We look forward to working cooperatively with other industry leaders to accelerate 10-Gigabit Ethernet technology,"" said Doug Ruby, vice president and chief technology officer of Lucent's Enterprise InterNetworking Systems group.

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