The rapid progress of IoT (Internet of Things) devices has allowed them to expand their range of applications in diverse fields including automobile industry, transportation system, healthcare and agriculture. Challenges in using IoT devices include traffic reduction, protocol efficiency improvement, reduction in communication delay. Message protocols for IoT include MQTT, Websocket and HTTP. MQTT has been expected for lightweight communication and simple implementation.We carried out a comparative analysis between protocols for IoT based on MQTT features in order to effectively use these protocols. We evaluate traffic in these protocols. We proposed the best way for topic name size.