Communication device, communication system, and session control method

A communication system comprising:

• an IP network;
• and a communication device configured to perform communication through the IP network in accordance with a session control protocol, wherein
• in route control devices in the IP network, different routes are preliminarily set for plural addresses assigned to the communication device, and
• the communication device includes a storage device configured to store the plural addresses, a user interface device, and a controller, wherein the controller executes
• processing that accepts an input of a user due to the user interface device, and
• address switching processing that causes a transmission destination address to be switched to another address included in the plural addresses in accordance with the session control protocol in response to the input, the transmission destination address being used by an opposite communication device, which communicates with the communication device, to transmit data to the communication device.

A session control method that controls a session due to a communication device performing communication through an IP network in accordance with a session control protocol, wherein

• the communication device includes a storage device configured to store plural addresses assigned to the communication device, a user interface device, and a controller, wherein
• the session control method causes the controller to execute
• processing that accepts an input of a user due to the user interface device, and
• address switching processing that causes a transmission destination address, used by an opposite communication device to transmit data to the communication device, to be switched to another address included in the plural addresses in accordance with the session control protocol, in response to the input.