Abstract: A segment and reassembly system cooperates with a data processing system for various kinds of data processing on ATM cells accumulated in frame buffers, and supplies ATM cells to ISDN after completion of various kinds of data processing; wherein the segment and reassembly system has processing units connected through exclusive interfaces to engines incorporated in the data processing system, and the engines process the pieces of data stored in the frame buffers at high speed, thereby improving the throughput of the segmentation and reassembly system.

Abstract: An internet protocol (IP) layer processor has an IP header processing section for checking a defect in an IP header of a first ATM cell of an AAL5 frame, and a SAR (segregation and reassemblage) section for transferring the AAL5 frame in the form of separate ATM cells if the check by the IP header processing section indicates a normal IP header, without using a CPU. SAR notifies a defect in the IP header to CPU without transmission of the AAL5 frame if the check indicates the defect in the IP header. The IP layer processor achieves a higher processing due to the direct transfer by the SAR without using processing by a software.

Abstract: A QoS server having an affinity to a protocol such as MGCP, capable of cooperating with applications without causing a delay in call setup and performing optimum QoS resource allocation is provided. A QoS server is provided with a network monitoring section for monitoring the network state, a network state database for storing network state information obtained at the network monitoring section, a resource allocation computing section for computing resource allocation for an application based on resource requirements with reference to the network state database, a resource allocation database for storing resource allocation information, and a network setup section for setting up the resource allocation on the network based on the resource allocation information.

Abstract: A sender transmits performance monitoring packets to a receiver via a network either prior to or in the midst of transmission appropriately, for monitoring communication quality (a communication delay, for example) of the network. A result of the monitoring is judged from returned performance monitoring result packets, whereby priority classes of communication packets are decided to perform subsequent transmission.

Abstract: A packet switch includes (a) a plurality of inputs into each of which a packet is input, (b) a switch which receives the packet from the input and switches an output through which the packet is transmitted, and (c) a scheduler which controls the switch. The scheduler (103) includes (c1) a shuffler (201) which shuffles an order of precedence in a first request transmitted from the input to transfer the packet, (c2) a schedule algorithm (202) which determines the output, based on the first request having the order of precedence having been shuffled by the shuffler, and produces a second request to transfer a packet which second request is associated with the first request having the order of precedence having been shuffled by the shuffler, and (c3) a re-shuffler (203) which turns an order of precedence of the second request to be identical with the order of precedence in the first request as found before having been shuffled by the shuffler, and returns the thus turned order of precedence back to the input.

Abstract: In an ATM network, each logical subnetwork comprises a server for resolving an ATM address using layer-3 address of request message and routing a packet to the network by using a layer-3 address of the packet. A source client examines a layer-3 header of a packet to determine whether its mode of transmission is connection-oriented or connectionless, and transmits the packet, if it is connectionless, to the server for causing it to route the packet through the network, and transmits, if the packet is connection-oriented, an ATM address resolution request message to the server. The source client receives a reply message from the server containing a resolved ATM address, and transmits a signaling message containing the resolved ATM address to the network to establish a connection. Over the established connection, the source client transmits data packets.

Abstract: The present invention is to provide a cell discard control system for an ATM (asynchronous transfer mode) cell buffer capable of preventing useless cells which are not restored to an original packet from being transmitted to an ATM network and minimize a discarded number of packets which should not be discarded.