Communication system and method

A communication system comprising:

• a first node including a first memory and a first processor coupled to the first memory;
• and
• a second node including a second memory and a second processor coupled to the second memory, wherein
• the first processor is configured to:
• obtain first information indicating reachability of data to the second node in a case of transmitting the data to the second node;
• specify a number of frames in a case of transmitting, to the second node, a file to be used for updating of software at the second node;
• specify, based on the first information and the number of frames, a transmission method candidate to transmit the file from the first node to the second node;
• and
• notify the second node of the specified transmission method candidate,
• the second processor is configured to:
• generate updating information indicating whether the software can be updated based on the file to be transmitted by the transmission method candidate;
• and
• notify the first node of the updating information, the first processor is configured to:
• specify a transmission method of the file from the transmission method candidate, based on the updating information;
• and
• transmit the file to the second node by using the specified transmission method, and
• the second processor is configured to execute the updating of the software by using the file transmitted from the first node.