APRIL 1--Leaders of the 1394 Trade Association (Grapevine, TX: www.1394ta.org), working in conjunction with the IEEE, have established a new study group to investigate methods of building IEEE 1394b (FireWire) links over up to 100 m of Category 5 wiring using existing Gigabit Ethernet (1000base T) physical-layer technology. Following approval by the chairman of the IEEE MSC, Bob Davis, Apple Computer hosted the first official meeting of the group March 3 in Cupertino, CA, where Apple's Michael Teener was named chairman. It will meet regularly and deliver technical results to the IEEE P1394 working group for incorporation into the revised IEEE 1394 base standard.
Key to the effort is specifying appropriate negotiation so that system endpoints can automatically select from various protocols, including 10BaseT Ethernet; 100BaseTX Ethernet; 100 Mbit/s 1394b; 1000BaseT Ethernet, and either 400 Mbit/s or 800 Mbit/s 1394. Glue logic between the 1000BaseT PHY and its adjoining, upper protocol layer appears as a standard interface to an Ethernet MAC and as a standard PHY/Link interface to an IEEE 1394 Link.
The group is considering using standard hub or switch technology to construct a basic hub that connects all endpoints and automatically senses the physical protocol (either Ethernet or IEEE 1394) used by the endpoint device. The hub also bridges the Ethernet and the IEEE 1394 segments so that Internet protocol devices seamlessly perceive each other as connected to the same subnet. Depending on the extent of the network and the desired performance level, the hub might connect IEEE 1394 devices as a single bus, or it might implement P1394.1 bridges and form a network from multiple buses. For the end user, the objective is to have a single RJ-45 socket labeled as "network" that works for any kind of connection.
