Patent ID: 8756456

Claim:
A method for downloading data from a server to a client, comprising: transmitting test packets from said server to said client, said test packets including a first test packet of a predetermined length transmitted via a first communication line of a relatively low communication speed, and a second test packet of a predetermined length transmitted via a second communication line of a relatively high communication speed; measuring a first period from start to completion of reception of said first test packet, and a second period from start to completion of reception of said second test packet at said client; transmitting said first period and said second period as information on a test result from said client to said server; receiving said first period and said second period at said server; starting transmission of data packets corresponding to said length of said second test packet from said server to said client via said second communication line; starting, at a point when a latency difference has passed since the start of transmitting said data packets via said second communication line, transmission of check packets corresponding to said length of said first test packet from said server to said client via said first communication line; and issuing a retransmission request to said server via said first communication line for any data packet that should have been received, provided that said data packet has not been received when said check packets are received at said client.