Research papers in IoT communication and networking protocols provide a comprehensive exploration of the technologies and methodologies that ensure reliable, efficient, and secure data exchange within the Internet of Things ecosystem. These works analyze lightweight application-layer protocols such as MQTT, CoAP, and AMQP that enable machine-to-machine communication with minimal overhead, alongside low-power wireless protocols like Zigbee, Z-Wave, Bluetooth Low Energy, and 6LoWPAN that are widely adopted in resource-constrained IoT environments. Long-range and wide-area connectivity solutions such as LoRaWAN, Sigfox, NB-IoT, LTE-M, and emerging 5G/6G standards are also studied for their ability to support large-scale deployments with extended coverage and massive device connectivity. Research further emphasizes the role of software-defined networking (SDN), network slicing, and edge–fog–cloud integration in optimizing resource allocation, ensuring interoperability, and enhancing quality of service (QoS). Advanced studies investigate cross-layer design, adaptive routing, congestion control, and energy-efficient scheduling to minimize latency and packet loss while extending network lifetime. Security-aware communication protocols leveraging blockchain, federated learning, and lightweight cryptographic algorithms are also highlighted as critical for addressing vulnerabilities in heterogeneous IoT networks. These research contributions span diverse application domains such as smart cities, connected healthcare, industrial IoT, precision agriculture, intelligent transportation systems, and smart grids, where communication protocols must adapt to dynamic environments and strict performance requirements. Collectively, this body of literature not only addresses the persistent challenges of scalability, interoperability, and resilience but also proposes next-generation protocol architectures that form the backbone of sustainable and intelligent IoT infrastructures worldwide.