Abstract: The FastSATME method and system estimate source-to-destination traffic matrices using a simulated annealing algorithm, the traffic matrix estimation being represented as a probability distribution over the set of all possible matrices that satisfy a set of given constraints. The constraints explicitly encode information that the user knows about the network traffic as components of an objective function (a fitness function), that is then minimized using simulated annealing. With the method according to the invention, arbitrary constraints of any form can be included. FastSATME works over a series of time steps. At the first time step FastSATME acts the same as SATME but in subsequent time steps, the estimate of the traffic matrix at time t is based on the estimate at t-1.

Abstract: Communication session admission control systems and methods are disclosed. A state of a communication system is monitored, and admission of a communication session into the communication system is controlled based on a random admission control procedure and a current state of the communication system. Monitoring of the current state of equipment in the communication system, connections in the communication system, communication sessions in progress in the communication system, special monitoring sessions established in the communication system, and/or an overall state of the communication system can have several benefits. These benefits may include improving utilization of resources in the system, and providing a session admission control scheme that is capable of reacting to actual observed conditions and adapting to changing system topologies following a fault, for instance.

Abstract: Apparatus and methods for real-time traffic classification based on off-line determined traffic classification rules are provided. Traces of real traffic are obtained and subjected to statistical analysis. The statistical analysis identifies domain the a multidimensional space of characteristic traffic parameters. Classification rules associated with the identified domains are derived and provided to traffic classification points for real-time traffic classification. Traffic classification points, typically edge network nodes, sample packets in aggregate streams with a predetermined probability. Statistical information regarding the sampled flows is tracked in a table, the number of time a flow was sampled providing a probabilistic measure of the flow's duration before the flow terminates. The table entries, which predominantly track high bandwidth flows, are subjected to the classification rules for real-time classification of the sampled flows.

Abstract: A packet switching node architecture is described in accordance with which multiple packets queued in input queues are considered in selecting packets to be forwarded via idle output ports. Considering multiple queued packets reduces the probability that an output port remains idle and increases the probability that each input queue is serviced despite forwarding of packets being blocked by contention. Also described are processes for enqueuing packets into, and dequeuing packets from, input queues, each input queue having associated therewith a multitude of head-of-line registers pointing to a corresponding sequence of head-of-line queue entries. Enqueuing ensures that the correct head-of-line registers point, in sequence, to a sequence of head-of-line queue entries. Servicing each input queue removes queue entries from the sequence, and dequeuing ensures the resequencing of the head-of-line pointers.

Abstract: The SATME method and system estimates source-to-destination traffic matrices using a simulated annealing algorithm, the traffic matrix estimation being represented as a probability distribution over the set of all possible matrices that satisfy a set of given constraints. The constraints explicitly encode information that the user knows about the network traffic as components of an objective function (a fitness function), that is then minimized using simulated annealing. With the method according to the invention, arbitrary constraints of any form can be included, and the case where there are no feasible solutions can be diagnosed by the objective function not converging to zero.

Abstract: A backpressure mechanism uses a TDM backpressure bus with each port card being assigned time slot. During its time slot, each ingress card/port writes on the bus the number of packets it transmitted to an egress ports during the last data refresh cycle. This information is read by the egress ports and used to compute current depth of the switch fabric output queues. In addition to information received from ingress cards, egress cards keep count of number of packets received from the appropriate switch fabric port and based on it estimate/calculate the current depth of the switch fabric output queue. Congestion states are calculated for all queues by comparing the queue depth with a respective threshold. Each egress card uses these congestion states to generate backpressure signals to ingress cards. Ingress card are using these signals to make decision whether to send or not traffic to destination egress card/port.

Abstract: A distributed, multistage agent for monitoring, diagnosis and maintenance of network devices comprises an input/output interface for receiving input monitoring and diagnostic data relevant to operation of a first neighboring agent and transmitting output monitoring and diagnostic data relevant to operation of the host network device to a second neighboring agent. An agent process analyzes the input data and generates processed data characterizing operation of the host network device, using a local database which stores expected performance data on operation of said network device. The processed data is correlated with the expected data any error is signaled to the network operator. The agents may be designed as a multiple stage process, the stages being triggered by the data output by an earlier stage only when needed.

Abstract: A cluster router architecture and methods for performing distributed routing are presented. The cluster router architecture includes off-the shelf Personal Computer (PC) hardware-based router cluster nodes interconnected in an intra-connection network in multiple dimensions. Each PC-based router cluster node is provided with the same routing functionality and a router-cluster-node-centric configuration enabling each router cluster node by itself or multiple router cluster nodes in the cluster router to provide routing responses for packets pending processing. Optimized packet processing in respect of specific functionality is provided via special purpose router cluster nodes not necessarily PC-based taking part as cluster nodes in the cluster router lattice. The method divides packet processing into entry packet processing and routing response processing; special processing; and exit processing.

Abstract: A method and apparatus for assessing a communications' network adherence to Service Level Agreements (SLAs) is presented. The apparatus includes a arrival curve parameter derivation and arrival curve parameter reporting means. A arrival curve parameter generator may be implemented either in hardware for a predefined response in fitting arrival curves to cumulative content arrival variations, or in software for flexibility in the content traffic considered for assessment. The arrival curve generator may be associated with a physical port, a line card, or a network node. Arrival curve parameters defining arrival curves are employed by a Network Management System (NMS) in conjunction with communications network node and communications network service curves in performing SLA conformance assessments.

Abstract: A cluster router architecture and methods for performing distributed routing is presented. Implementations include off-the shelf Personal Computer (PC) hardware. The cluster router architecture includes PC-based router cluster nodes toroidally interconnected in an intra-connection network in multiple dimensions. The cluster router may further make use of a management node. Each router cluster node is provided with the same routing functionality and a node centric configuration enabling each router cluster node by itself or multiple router cluster nodes in the cluster router to provide routing responses for packets pending processing. The method divides packet processing into entry packet processing and routing response processing; and exit processing. Entry packet processing and routing response processing is performed by router cluster nodes receiving packets from communication networks in which the cluster router participates.