ZigBee gets an IP-based rival

The wireless sensor network standard ZigBee should be worried, according to a company launching a rival based on the universal network standard, IP.

PhyNet, launched Monday by Arch Rock Corporation, connects wireless-equipped devices into a low-power mesh network using the IEEE 802.15.4 wireless protocol, just as ZigBee does, but the new contender uses IP, which allows it to be more extensible and connect directly to companies' own data networks, according to Arch Rock.

"ZigBee is not based on IP, because the conventional wisdom, when it was defined, was that IP had too much overhead," said Roland Acra, president and chief executive of Arch Rock. "We have proved you can do IP in a very compact way, in low-power, low-bandwidth devices, and get the best of both worlds."

Arch Rock has contributed to RFC 4944, an IETF standard for IP over 802.15.4 networks, and a year ago produced a Primer Pack for making pilot projects using IP over low-power WSNs (wireless sensor networks).

PhyNet, the production version, allows a tiered architecture, said Acra. It has a server to manage collections of WSNs, and a PhyNet router which links each sensor network on to the corporate IP network. Other networks need to have a controller co-located with every sensor network. "Sensor applications can be half a world away, across a corporate campus or in the next room," said the Arch Rock release.

The product family also includes nodes, which can connect to analog and digital sensors, including existing data loggers. "Our customers are now entering a phase where they want to connect and centrally manage multiple sensor-equipped buildings," said Acra. "PhyNet allows management services and applications to reside in a protected corporate datacenter."

If traffic increases in a sensor network, extra routers can be added, each one increasing the throughput by 250Kbps and providing resilience.

ZigBee proponents don't appear to be worried. "ZigBee/15.4 and IP/15.4 are both likely to have a future in embedded networking; ZigBee has a present too," was the wry comment from Bob Metcalfe, whose investment company backs ZigBee chipmaker Ember.

Metcalfe has an interesting history with standards. Having invented Ethernet, he famously predicted the end of the Internet in 1995. This time round, he's not underestimating IP, but says, "Just cramming IP packets into 15.4 packets is not nearly enough for embedded networking. ZigBee solves a lot of other problems too."

ZigBee is being implemented in home automation and metering systems, said Metcalfe, while Arch Rock's customers appear to be more industrial: "Our stuff lives in the dirty fingernail world -- on goods trains and up poles," said Acra. So the two may actually be aiming at different areas.

Arch Rock is selling an entry-level PhyNet system, with 10 nodes, two routers, and a server, for $7,995.