The discovery and the use of many wireless technologies are paving way for new remote monitoring applications. The sensing devices are becoming popular because of their flexibility, performance, low cost and portability. Wireless Sensor Networks (WSN) is a good alternative to wired systems because of easy deployment in remote areas. Wireless Sensor Networks are used in different domains for various applications because of their salient characteristics like reduced power consumption, scalability, ability to respond immediately within a short span of time, reliability, dynamic in nature, low cost and easy installation. The main objective of this paper work is to find a suitable energy efficient, scalable and reliable communication protocols for intra-cluster and intercluster communication. Therefore the proposed research work follows three different phases. To achieve the desired results, the proposed research work concentrates on three protocols namely Energy Efficient and Reliable Clustering Routing Protocol (EERCRP), Energy Efficient and Reliable MAC Protocol (EERMAC) and Energy Efficient and Reliable Hybrid Transport Protocol (EERHTP).EERCRP and EERMAC are intra-cluster communication protocols that help in cluster formation and effective data sensing. EERHTP is a transport layer protocol that is used for inter-cluster communication. All the above protocols are evaluated using network simulator NS2 for their performance analysis. EERCRP is compared with PASCC and PCDCC which from the root level header node are existing congestion and queue based hybrid clustering protocols. The proposed EERCRP follows hierarchical cluster formation where the leader node is selected based on queue length, residual energy of the node and distance. It is efficient than the existing methods in terms of energy and reliability metrics.EERMAC is compared with existing MAC protocols namely SMAC, IEEE 802.11 EDCA and EA-MAC. SMAC follows traditional TDMA or CSMA method of data access. They are suitable only for periodic data sensing. The proposed EERMAC allows hybrid data sensing consisting of both periodic and event based data which are classified using priority levels. Event based data is assigned higher priority than periodic data. Queues are used for storing both types of data using various levels of threshold values. EERMAC uses CSMA/CA method for event based data. Variable TDMA method is used for event based and periodic data. EERHTP is a transport layer protocol that uses two types of reliability models namely ACK and NACK depending on the type of data. All the three protocols are evaluated both for energy and reliability metrics such as total energy consumption, residual energy comparison, energy consumption per packet, packet delivery ratio, delay, packet drop, jitter, throughput and network routing overhead. Thus it is concluded that all the three protocols are more optimal than the existing protocols and prove to be the best protocols for intracluster and inter-cluster communications.