Add-drop multiplex functions packed in one chip

PMC-Sierra Inc. released a device that combines a full OC-3/OC-12 add-drop multiplexer on a single chip with associated circuitry. The ADM 622 will target "pizza box" remote-terminal designs. Startup Parama Networks is among those that already offer single-chip ADM solutions. But PMC-Sierra said its offering will be a better option for carriers because of its focus on OC-3/OC-12, rather than OC-192, rates.

"There aren't many 10Gb-rings out there," said product-marketing engineer Babak Samini. "We're targeting the higher-volume remote-terminal market. In these designs, OC-3/OC-12 is the sweet spot."

Samini said the ADM 622 combines the capabilities of framer, mapper, virtual-tributary cross-connect and pointer processor. "Many of the other ADM chips [in the market] need a lot of FPGAs around them."

The ADM 622's dual OC-3 and OC-12 network interfaces are independently configurable and can interface directly to the line without external clock-and-data recovery circuitry. The chip also provides 28 T1 and 21 E1 transport interfaces, three DS3/E3 transport interfaces, a telecom bus interface and a serial expansion interface.

To support the delivery of Ethernet traffic over Sonet pipes, an Ethernet-over-Sonet mapper block delivers eight Fast Ethernet interfaces and one Gigabit Ethernet interface. This block can map Ethernet traffic into high-order or low-order Sonet pipes using the generic framing procedure and virtual concatenation.

A full virtual-tributary (VT) cross-connect block can handle switching and grooming on more than 2,000 VTs. "The cross-connect can take 2.5Gb worth of traffic and switch it down at the VT level," Samini said. The cross-connect supports 1+1, 1:1, unidirectional-path switched-ring network configurations.

The ADM 622 is developed in a 0.13?m process. Housed in an 896-ball flip-chip BGA, it draws between 6W and 7W. A version without the Ethernet-over-Sonet mapper block is also offered. General sampling is scheduled to start in the fourth quarter.

- Robert Keenan

ComssDesign.com