ZigBee spec on deck
Sensor networks mature
Wireless Alert
By
Joanie Wexler
,
Network World
, 11/08/2004
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Joanie Wexler looks at how enterprises can take advantage of wireless LANs and WANs.
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It's been quite some time since I mentioned ZigBee, the emerging low-cost sensor network based on IEEE 802.15.4 wireless standards
in the 2.4 GHz band. Well, the ZigBee 1.0 specification is poised for publication this month - and possibly as early as this
week.
The forthcoming spec defines the network, security and application software layers above the physical and MAC layers defined
in 802.15.4.
In addition, the ZigBee Alliance, a consortium of technology companies, plans to announce a conformance and interoperability
certification program, according to alliance board member Jon Adams, who is also director of radio technology and strategy
at Freescale Semiconductor.
ZigBee represents an industry initiative to enable the construction of business and residential network applications using
low-cost, low-power sensors that run on batteries with very long lives. Among these applications are lighting control; heating,
ventilating and air conditioning (HVAC) environmental management; and industrial sensors.
Hotel sensor networks, for example, could automatically determine when there's no one in a room and then turn off lights,
heat and air conditioning to conserve energy. Similarly, hotels could keep a guest's profile with room temperature preference
on file, and the room could automatically be programmed to adjust to that environment upon guest check-in.
At the network layer, ZigBee specifies how the sensor network forms (in a mesh configuration), heals itself, grows, and routes
messages, Adams explains. For security, 802.15.4 specifies 128-bit Advanced Encryption Standard encryption, but nothing about
how to manage encryption keys. So ZigBee specifies key management.
At the application layer, ZigBee 1.0 has already defined basic applications for lighting, HVAC and industrial sensors; developers
can simply add their own look and feel. For application developers who choose not to use the standard ZigBee profile, there
are API calls in the 1.0 spec that define rules for how applications speak to the ZigBee system, Adams says.
Joanie Wexler is an independent networking technology writer/editor in Silicon Valley.
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