The ZigBee Address is a unique 64-bit identifier assigned to each ZigBee device by the manufacturer. ZigBee Addresses are usually displayed as 8 bytes written in hexadecimal and separated by colons (example - DF:3B:00:11:22:33:FF:EE). They are an essential part of ZigBee-based protocols. The most-significant 24 bits of the ZigBee address is the so-called Organizationally Unique Identifier (OUI). It can be used to determine the manufacturer of a device. OUI prefixes are assigned by the Institute of Electrical and Electronics Engineers (IEEE). An EUI (Extended Unique Identifier) is generally made from an OUI and thus a ZigBee Address is also an EUI-64. When a ZigBee device joins a network it is assigned an additional 16-bit address sometimes referred to as its network address. This address is different from the 64-bit ZigBee address and is dynamic.