Abstract: A repeater such as an Internet router device used in a communication network such as the Internet. The delay time from a device of a sender to a device of a receiver is secured. A communication system, a control circuit, a connecting means, and a computer program are also disclosed. The sending time intervals between sending to a transmission network are calculated from a target value of the transfer rate of a packet to be relayed (S202), a target value of the delay time is determined on the basis of the delay time to be secured (S205), and a reference value of the storage capacity used as a criterion for deciding discard of a packet is calculated from the delay time target value and the sending time intervals (S206). Packets are sent out at the calculated sending time intervals, and discard of a packet is judged according to a predetermined method when a packet having a storage capacity above the storage capacity reference value is received.

Abstract: An output port circuit is provided for a router apparatus which routes and transmits a received packet. Each flow is constituted by continuous packets and belongs to a bandwidth-guaranteed class or a best-effort class. A controller controls storage and reading of a packet into and from a storage unit. Upon allocating a basic volume that is a criterion of a memory size stored in the storage unit to each flow to which the packet to be transmitted belongs, the controller manages the basic volume of each flow of the packet belonging to the bandwidth-guaranteed class by individually allocating the basic volume by the memory size required by each flow, and manages the basic volume of each flow of the packets belonging to the best-effort class by collectively allocating the memory size obtained by subtracting a sum of respective basic volumes allocated to the bandwidth-guaranteed class from an entire memory size.

Abstract: An output port circuit is provided for a router apparatus which routes and transmits a received packet. Each flow is constituted by continuous packets and belongs to a bandwidth-guaranteed class or a best-effort class. A controller controls storage and reading of a packet into and from a storage unit. Upon allocating a basic volume that is a criterion of a memory size stored in the storage unit to each flow to which the packet to be transmitted belongs, the controller manages the basic volume of each flow of the packet belonging to the bandwidth-guaranteed class by individually allocating the basic volume by the memory size required by each flow, and manages the basic volume of each flow of the packets belonging to the best-effort class by collectively allocating the memory size obtained by subtracting a sum of respective basic volumes allocated to the bandwidth-guaranteed class from an entire memory size.