It is not uncommon for malicious devices in a communication network to attempt to compromise the network, thereby preventing legitimate devices from enjoying the services of the network. Such an attack is called a “denial-of-service” (DoS) attack. When multiple devices, e.g., a botnet, simultaneously launch a DoS attack, it is known as a Distributed DoS (DDos) attack.
Malicious devices may attack a communication network that employs a “session signaling” or “session control” protocol. Such a protocol may create, modify, and terminate sessions (e.g., telephone calls, instant messaging conferences) among participants of the session. Session Initiation Protocol (SIP) is one such session signaling protocol, e.g., an application-layer protocol for creating, modifying, and terminating sessions.