Packet compression system, packet restoration system, packet compression method, and packet restoration method

A packet compression method comprising:

• a reception step of receiving at least one uncompressed packet, the uncompressed packet including a header and a payload of a second OSI layer, the payload of said second OSI layer including a header and a payload of a third OSI layer, the payload of said third OSI layer including a header and a payload of a fourth OSI layer, the payload of said fourth OSI layer including a codec signal;
• a compression step of generating a compressed packet in which at least one said codec signal is inserted into the payload of said second layer without interposition of said third OSI layer and said fourth OSI layer by deleting the header of said third OSI layer and the header of said fourth OSI layer from said uncompressed packet;
• and
• a transmission step of transmitting said compressed packet,
• wherein in said compression step, the number of codec signals inserted into the payload of said second OSI layer of said compressed packet is changed with passage of time so that the number of said compressed packets transmitted per unit time in said transmission step does not exceed a predetermined value irrespectively of the number of said uncompressed packets received per unit time in said reception step.