Based on end user application a network of hundreds or even thousands of sensor nodes, also known as wireless sensor network, can collect valuable data from an unassisted environment and transmit the information to the user. This transmission can be routed from one node to another using numerous routing protocols for wireless sensor network. Though purposive, there are some constraints of the sensor nodes due to computing power, storage capacity and limited power.
In this review article, we will discuss wireless sensor network’s architecture. Further, we will discuss classification of routing protocols according to some factors and summaries on their mode of operation. Lastly, we put up a comparative study on these protocols.