Which technique changes protocols at random during a session?

Port hopping is a technique that changes protocols at random during a session to evade detection and analysis by security devices. Port hopping can be used by malware or attackers to communicate with command and control servers or to exfiltrate data. Port hopping makes it difficult to identify and block malicious traffic based on port numbers or signatures. References: Port Hopping, Ports Used for Management Functions, Adding a Custom Application/Ports to Security Policy