ZigBee technology is developed to support automation, wireless remote control,

monitoring and personal area network applications. The IEEE 802.15.4 committee

was formed a short while later after inception of ZigBee to work on a low data rate

standard. Thereafter the ZigBee Alliance and the IEEE joined together for further

development of the standard and the technology was commercially named as Zig-

Bee [1]. It is developed keeping those applications in mind which have a relaxed

bandwidth requirement, require a self organizing short-range wireless communica-

tion network and are unable to handle the battery discharge to power the heavy pro-

tocol stack. IEEE 802.15.4 is a global standard that was developed for Low-Rate

Wireless Personal Area Network (LR-WPAN) to cater to the requirements of slower

data transmission rates, low power requirements, durability, maintenance-free oper-

ation and cheaper cost. The target of this standard was to provide networking at an

inexpensive cost among the devices which may be fixed or mobile in a home or in-

dustrial network. It provides connectivity to equipment that does not require a high

data transfer rate like those in Bluetooth but should sustain its battery life for a few

years. ZigBee is based on IEEE 802.15.4 standard which is very less complex than

the Bluetooth due to reduced Quality of Service (QoS) [2] [3]. 802.15.4 defines only

45MAC primitives and 14 PHY primitives [4][5]. ZigBee addresses the unique needs

of sensor network applications by providing logical network, interoperable data net-

working, security services, wireless home and building control solutions, interoper-

able compliance testing and other application layer primitives in the upper protocol

layer which has the IEEE 802.15.4 at the lower layers. IEEE 802.15.4 provides spec-

ifications for the physical and data link layer and ZigBee alliance provides standards

from network layer to application layer. While ZigBee determines the contents of

the transmitted message, the 802.15.4 standard provides details about the robust ra-

dio hardware (PHY) and medium access control (MAC) to use for transmission [6].

There are two types of devices in ZigBee: the Fully Functional Devices (FFD) and

the Reduced Function Devices (RFD). A network should include at least one FFD,

which should take the role of PAN coordinator. An FFD can discover [7] and com-

municate with another FFD as well as an RFD. In order to provide seamless commu-

nication in the network based on the characteristic features of these devices, ZigBee