| 摘要 |
A protocol processing portion 11 performs SSCOP processing while referring to protocol parameters stored in a parameter managing portion 12. The parameter managing portion 12 includes a parameter changing portion and a parameter table. The protocol parameters required in performing the SSCOP processing in the protocol processing portion 11 are stored in the parameter table. The parameter changing portion changes the value of a prescribed protocol parameter (MaxPD) in the parameter table depending on the number of data packets whose transfer is required at one time by a data transfer application 14. A connection setting portion 13 sets a logical channel between the data transfer device and a data transfer device which is a destination of communication through an ATM network 17, to allow data transfer. The data transfer application 14 sets a logical channel between the data transfer device and a device which is a destination of data transfer upon instructing the connection setting portion 13, then assembles data to be transferred into packets, and requires transmission of the packet data of the protocol processing portion 11. A communication control portion 15 sends out to the ATM network 17 control data for setting the logical channel given by the connection setting portion 13 or the packet data given by the protocol processing portion 11. Such construction makes it possible to send out a delivery confirmation packet (POLL) immediately after the data packets continuously sent out, and quickly confirm the delivery of the data. Consequently, a data region held by a device on the transmission side can be quickly released, so that the data region can be efficiently used. Further, a window size is updated immediately after the data transfer, thereby it is possible to avoid situations where the window size is not updated by the impossibility of the confirmation of the delivery. As a result, even when data high in real time properties such as video data is transferred, it is possible to exhibit a sufficient performance. <IMAGE> |
