CHICAGO Efforts to marry StarGen Inc.'s switch-fabric technology to the CompactPCI bus architecture took some key steps forward at the Embedded Systems Conference, held this week in Chicago.
StarGen, a fabless semiconductor startup, demonstrated its SG 1010 StarFabric Switch chip for the first time at the show. This serial switch provides 2.5-Gbit/second full duplex on each of its six links. The switches are cascadable, which means designers can connect switches to switches and create very large switching topologies.
The 0.18-micron CMOS device is implemented in a PBGA, 272-pin package. Although pricing hasn't been decided yet, StarGen said it expects the switch to sell for about $75.
Other StarFabric chips announced earlier this year include a TDM-to-StarFabric bridge device from Agere Systems Inc. (Allentown, Pa.) and a PCI-to-StarFabric bridge chip from StarGen. The StarFabric Bridge chip, SG 2010, provides access to the switch f abric from existing PCI standard interconnects.
In conjunction with the demo, the PCI Industrial Computer Manufacturers Group kicked off the PICMG 2.17 subcommittee. Its mission is to craft a StarFabric CompactPCI specification that defines backplane, node card and switch card requirements that are compatible with both the StarFabric Protocol Specification and appropriate existing PICMG specifications.
The StarFabric Interconnect specifications will define redundant, switched, high-speed point-to-point connectivity among some or all slots using StarFabric switch cards. The StarFabric interconnect will coexist with 64-bit PCI, CompactPCI and H.110. The spec will provide optional compatibility with cPSB (PICMG 2.16). Systems that take advantage of StarFabric features can be designed to utilize existing single-board computers and node cards. Special slots for active switching-fabric elements, which may be redundant, will also be specified.
Board to backplane
"The spec won't get into the protocol of StarFabric, but rather how you implement it in a CompactPCI environment," said Tim Miller, vice president of marketing for StarGen and chairman of the PICMG 2.17 working group. "The spec will define pinouts and how to run StarFabric switch links from boards onto the backplane." Miller reported huge interest among PICMG members, with an unprecedented 65 companies signing on to the effort.
"We'd like to get this spec approved and back through the PICMG executive group by the second quarter of 2002," Miller said. "That's fairly rapid for an effort like this." Miller said the spec will require some signal-analysis work.
Miller pointed to communications access equipment as the key focus for StarFabric. Applications including DSL access multiplexers, media gateways and multiservice access systems are expected to be a good fit. The technology offers applications scalability while making it easy to support the multiple traffic types used by access equipment.
The earliest adopters of the Star Fabric architecture will likely be voice-over-Internet Protocol (VoIP) gateways and other multiservice boxes that deal with voice traffic. In March Agere revealed the details of its Ambassador T8150 TDM-to-StarFabric bridge chip. It functions as a bridge between the TDM voice signals over the H.100/H.110 bus and the StarFabric switch fabric. It is able to connect 128 H.100/H.110 bus segments together to offer up to 128 times the voice-processing capacity of typical H.100/H.110 products. Used in conjunction with StarGen's PCI bridge and switch chips, the Ambassador T8150 provides all the pieces required to deploy a full switch-fabric-based VoIP system.
Beyond access communications, StarFabric is expected to serve as a means to scale up CompactPCI-based systems. StarFabric serializes the PCI bus with no penalties in speed or to software transparency and links it between nodes via a switch fabric.