The IEEE 802.15.4 is a new standard defined for LR-WPAN which provides a low cost and very less complicated solution. The targeted applications are Wireless Sensors Networks (WSN), interactive toys, home automation and remote controls. ZigBee is one of the newest technologies developed by ZigBee Alliance, enabling Wireless Personal Area Networks (WPAN). ZigBee is the name of a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4 standard. This paper includes the introduction to Network Nodes and Topology supported by IEEE 802.15.4/ZigBee Standard, also the authors have discussed the standard routing protocols used in the ZigBee standard.