Data delivery system, communication device, and communication control method

A communication device comprising:

• a monitoring unit configured to monitor an operation state of a second communication device, the second communication device being in one level higher than the communication device in a logical network forming a tree structure and sending data to the communication device;
• and
• a connection switching unit configured to, when the normal operation state of the second communication device is not confirmed by the monitoring unit, send a request for sending data to a third communication device, the third communication device being in two or more levels higher than the communication device in the logical network and being configured to send data to the communication device, without passing through the second communication device.

A communication control method of a first communication device of a data delivery system comprising a plurality of communication devices, comprising the first communication device, a second communication device, and a third communication device, and performing data delivery using a logical network forming a tree structure, the second communication device being in one level higher than the first communication device in the logical network and sending data to the first communication device, the third communication device being in two or more levels higher than the first communication device in the logical network and being configured to send data to the first communication device without passing through the second communication device, comprising:

• monitoring an operation state of the second communication device;
• and
• sending a request for sending data to the third communication device, in a case that the normal operation state of the second communication device is not confirmed.