Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and other low-power low-bandwidth needs, designed for small scale projects which need wireless connection.

Hence, Zigbee is a low-power, low-data-rate, and close proximity (i.e., personal area) wireless ad hoc network.

Zigbee is typically used in low data rate applications that require long battery life and secure networking.

Zigbee builds on the physical layer and media access control defined in IEEE standard 802.15.4 for low-rate wireless personal area networks (WPANs).

Another defining feature of Zigbee is facilities for carrying out secure communications, protecting the establishment and transport of cryptographic keys, ciphering frames, and controlling devices.

The library is a set of standardised commands, attributes and global artifacts organised under groups known as clusters with names such as Smart Energy, Home Automation, and Zigbee Light Link.

[12][13][dubious – discuss] Typical application areas include: Zigbee is not for situations with high mobility among nodes.

[19] It adds services for plug-in electric vehicle charging, installation, configuration and firmware download, prepay services, user information and messaging, load control, demand response and common information and application profile interfaces for wired and wireless networks.

It promised many advantages over existing remote control solutions, including richer communication and increased reliability, enhanced features and flexibility, interoperability, and no line-of-sight barrier.

The actual data throughput will be less than the maximum specified bit rate because of the packet overhead and processing delays.

For indoor applications at 2.4 GHz transmission distance is 10–20 m, depending on the construction materials, the number of walls to be penetrated and the output power permitted in that geographical location.

In this type of network, Zigbee routers typically have their receivers continuously active, requiring additional power.

In non-beacon-enabled networks, power consumption is decidedly asymmetrical: Some devices are always active while others spend most of their time sleeping.

Except for Smart Energy Profile 2.0, Zigbee devices are required to conform to the IEEE 802.15.4-2003 Low-rate Wireless Personal Area Network (LR-WPAN) standard.

Once the destination is reached, a route reply is sent via unicast transmission following the lowest cost path back to the source.

This layer binds tables, sends messages between bound devices, manages group addresses, reassembles packets, and transports data.

The application support sublayer (APS) is the other main standard component of the stack, and as such it offers a well-defined interface and control services.

A network node consists of an IEEE 802.15.4-conformant radio transceiver and one or more device descriptions (collections of attributes that can be polled or set or can be monitored through events).

Furthermore, binding is decided upon by matching input and output cluster identifiers[clarify] unique within the context of a given profile and associated to an incoming or outgoing data flow in a device.

Binding requires an established communication link; after it exists, whether to add a new node to the network is decided, according to the application and security policies.

As one of its defining features, Zigbee provides facilities for carrying out secure communications, protecting the establishment and transport of cryptographic keys and encrypting data.

A momentary exception to this rule occurs during the initial phase of the addition to the network of a previously unconfigured device.

Within the protocol stack, different network layers are not cryptographically separated, so access policies are needed, and conventional design assumed.

As malicious devices may exist, every network layer payload must be ciphered, so unauthorized traffic can be immediately cut off.

The exception, again, is the transmission of the network key, which confers a unified security layer to the grid, to a new connecting device.

A key can be associated either to a network, being usable by Zigbee layers and the MAC sublayer, or to a link, acquired through pre-installation, agreement or transport.

Ideally, devices will have the trust center address and initial master key preloaded; if a momentary vulnerability is allowed, it will be sent as described above.

Typical applications without special security needs will use a network key provided by the trust center (through the initially insecure channel) to communicate.

The security architecture is distributed among the network layers as follows: According to the German computer e-magazine Heise Online, Zigbee Home Automation 1.2 uses fallback keys for encryption negotiation which are known and cannot be changed.

In addition, the Zigbee 3.0 protocol features countermeasures against removing already paired devices from the network with the intention of listening to the key exchange when re-pairing.