Abstract: A packet-switched communication network in accordance with the invention provides a guaranteed minimum bandwidth between pairs of Packet Switches by defining Service Level Agreements (SLAs). An SLA is defined by at least a source identifier, a destination identifier, and a minimum data rate although other information can also be used. Upon arrival at certain networked nodes, packets are classified according to an SLA by reading the source and destination addresses in the packet. Once classified, the packets are placed in a queue and scheduled for transmission. A scheduler ensures that packets are transmitted at the minimum defined data rate for the SLA. The scheduler may use a statistical multiplexing method, such as deficit round robin, or deficit golden ratio, which is part of the present invention. The deficit golden ratio method assures a minimum rate to packets for a particular SLA, but minimizes jitter and delay.

Abstract: The invention provides a method and system for collecting aggregate information about network traffic, while maintaining processor load relatively constant despite substantial variation in network traffic, and capable of substantially accurate frequency measurement even for relatively infrequent events. A packet monitoring system includes an input port for receiving network packets, a sampling element for selecting a fraction of those packets for review, and a queue of selected packets. The packets in the queue are coupled to a packet-type detector for detecting packets of a selected type; the system applies a measurement technique for determining a frequency measure for those detected packets. The system includes a feedback technique for adaptively altering the sampling rate fraction, responsive to the queue length and possibly other factors, such as processor load or the detected frequency measure.

Abstract: A packet-switched communication network in accordance with the invention provides a guaranteed minimum bandwidth between pairs of Packet Switches by defining Service Level Agreements (SLAs). An SLA is defined by at least a source identifier, a destination identifier, and a minimum data rate although other information can also be used. Upon arrival at certain networked nodes, packets are classified according to an SLA by reading the source and destination addresses in the packet. Once classified, the packets are placed in a queue and scheduled for transmission. A scheduler ensures that packets are transmitted at the minimum defined data rate for the SLA. The scheduler may use a statistical multiplexing method, such as deficit round robin, or deficit golden ratio, which is part of the present invention. The deficit golden ratio method assures a minimum rate to packets for a particular SLA, but minimizes jitter and delay.

Abstract: A system and method in accordance with the invention provides efficient allocation of network resources to network virtual connections while providing reliable and guaranteed quality of service. Such a system is generally used in a network that includes a plurality of nodes and a plurality of links interconnecting the nodes. In accordance with an embodiment of the invention, for each connection in the network established between a pair of nodes, a normal path ni between the nodes having a rate Ni is established and an alternate, or backup, path bi having a rate Bi is established. Information is only transmitted on the backup path in the event of a failure on the normal path. The system further maintains information for each link as to the resources, such as bandwidth, utilized by the connections. The system then utilizes the maintained information to determine whether new connections can be accommodated and still meet quality of service guarantees.

Abstract: Disclosed herein is a system and method to implement end-to-end QoS for connections in IP-based networks, even when the communications are between different subnetworks. In accordance with an embodiment of the invention, QoS is provided between subnet routers that are attached to the network through a network backbone. An embodiment of the invention can differentiate connections between routers and can classify data streams for both inter-subnet and intra-subnet connections using only information provided in the IP headers and without requiring any special tags or other identifiers to be added to the packet.

Abstract: A packet-switched communication network in accordance with the invention provides a guaranteed minimum bandwidth between pairs of Packet Switches by defining Service Level Agreements (SLAs). An SLA is defined by at least a source identifier, a destination identifier, and a minimum data rate although other information can also be used. Upon arrival at certain networked nodes, packets are classified according to an SLA by reading the source and destination addresses in the packet. Once classified, the packets are placed in a queue and scheduled for transmission. A scheduler ensures that packets are transmitted at the minimum defined data rate for the SLA. The scheduler may use a statistical multiplexing method, such as deficit round robin, or deficit golden ratio, which is part of the present invention. The deficit golden ratio method assures a minimum rate to packets for a particular SLA, but minimizes jitter and delay.

Abstract: In a packet-switched network, a distributed performance measurement system is disclosed. In each node, a node monitor maintains information for each virtual channel passing through the node, including a list of the arrival times of the packets queued for the virtual channel. In addition, each node determines node performance characteristics, which may include throughput, effective rate, delay, loss rate, and occupancy. The network further includes a network monitor, which periodically collects the node performance characteristics from each node and determines performance characteristics for each virtual channel in the network, end-to-end. The network performance characteristics may include throughput, effective rate, delay, loss rate, and occupancy. The results are useful for network operators and users to optimize the network and/or their use of the network.

Abstract: A packet-switched communication network in accordance with the invention provides a guaranteed minimum bandwidth between pairs of Packet Switches by defining Service Level Agreements (SLAs). An SLA is defined by at least a source identifier, a destination identifier, and a minimum data rate although other information can also be used. Upon arrival at certain networked nodes, packets are classified according to an SLA by reading the source and destination addresses in the packet. Once classified, the packets are placed in a queue and scheduled for transmission. A scheduler ensures that packets are transmitted at the minimum defined data rate for the SLA. The scheduler may use a statistical multiplexing method, such as deficit round robin, or deficit golden ratio, which is part of the present invention. The deficit golden ratio method assures a minimum rate to packets for a particular SLA, but minimizes jitter and delay.