Transmitting apparatus and transmission rate control method

A transmitting apparatus for transmitting a packet to a plurality of receiving apparatuses through a network, the plurality of receiving apparatuses being classified into a plurality of classes based on an available bandwidth for the plurality of receiving apparatuses, the packet being transmitted on a per class basis and including, in a header, a receiver list in which one or more receiving apparatuses that belong to a class for transmitting the packet are registered, the transmitting apparatus comprising:

• a receiving section that receives the packet from a receiving apparatus, the packet further including information about a transmission capability of the receiving apparatus;
• an available bandwidth estimating section that estimates the available bandwidth for the receiving apparatus, from the information included in the received packet;
• a bandwidth correcting section that calculates a header size of each class from a number of receiving apparatuses that belong to each class, and corrects the available bandwidth based on a difference of the header size between each class;
• and
• a class determination processing section that determines a class to which the receiving apparatus belongs, based on the corrected available bandwidth, and registers the receiving apparatus in the receiver list, wherein the bandwidth correction section:
• calculates a bandwidth correcting coefficient for the available bandwidth, by calculating a packet size for the class that is formed with the calculated header size and a payload size for the class, and by dividing the packet size for the class by a packet size for an upper class;
• and
• corrects the available bandwidth by multiplying the available bandwidth with the calculated bandwidth correcting coefficient.