Packet transmission method and nodes

A receiving node comprising:

• a control unit that
• measures a time taken for feedback indicating that a packet including context information has been lost, and that
• causes a transmitting node to switch between a first mode and a second mode based on the measured time taken for the feedback, the first mode being a mode for periodically transmitting a packet including the context information and the second mode being a mode for transmitting the packet including the context information in response to the feedback from the receiving node.

A transmitting node comprising:

• a measurement process unit that
• receives, from a receiving node, a measurement request requesting to measure a time taken for feedback from the receiving node, the feedback indicating that a packet including context information has been lost, and that
• transmits a measurement response indicating an elapsed time from when the measurement request is received.