Cisco Technology, Inc.

Sun Microsystems, Inc.

Attune Networks Ltd.

Viola Networks Ltd

Moshe Sidi

Israel Cidon

Raphael J Rom

Asad Khamisy

Lior Z Horn

Yair Harel

Benny Rachlevski-Reich

Benny Zangiri

Shlomit Botton-Dascal

Phanindra Jujjavarapu

Man-Tung Tony Hsiao

Arie Kazatcker

Roee Mitrani

Lior Horn

Uri Keidar

Asad Khamisky

A method for testing a communication network includes transmitting a flow of test packets over a path through the network. The flow includes a series of bursts of the test packets separated by intervals having an interval duration, each burst comprising a sequence of the test packets and having a burst duration less than the interval duration. Arrival characteristics of the test packets in the flow are measured at a receiving end of the path. The arrival characteristics include at least one of a packet loss characteristic, a packet delay characteristic, and a packet jitter characteristic. A quality defect in the network is detected based on the measured arrival characteristics.

Sampling test of network performance

Network testing is conducted using a pair of traffic agents that acts as sender and receiver endpoints. The sending traffic agent generates and transmits a stream of packet batches, each batch being composed of high and low priority packets in a predetermined sending order. The receiving traffic agent analyzes the order of packet arrival in the stream relative to the sending order, and returns results to a traffic control module. Path speed and the priority classification of the traffic are parameters used to configure the tests. The tests are typically run periodically under different load conditions in order to evaluate the effects of other traffic being concurrently transiting the network.

Quality of service testing of communications networks

A method for testing of a communication network, using a plurality of traffic agents coupled to communicate via the network. The method includes transmitting a sequence of data packets via the network from a first one of the traffic agents to a second one of the traffic agents and recording arrival characteristics of the packets in the sequence, responsive to receiving the packets at the second traffic agent. The arrival characteristics of different packets in the sequence are compared so as to determine a measure of variability in transmission of the packets via the network.

Analysis of network performance

A method for testing a communication network includes transmitting at least one unidirectional flow over a path through the network, and measuring arrival characteristics of the least one unidirectional flow at a receiving end of the path. The arrival characteristics include at least one of a packet throughput characteristic, a packet delay characteristic, a packet loss characteristic, a packet jitter characteristic and a packet misordering characteristic. A bidirectional flow is transmitted over the path from both ends of the path simultaneously, and the arrival characteristics of the bidirectional flow are measured at least at one of the ends. The arrival characteristics of the unidirectional and bidirectional flows are compared in order to detect a fault in the path.

Duplex mismatch testing

A method for testing of a communication network having a plurality of end-points, using one or more network agents coupled to the network at respective locations. The method includes specifying at least one packet filtering criterion, and transmitting one or more data packets meeting the at least one criterion through the network from one of the end-point to another. At least one of the data packets meeting the criterion is intercepted using the network agents at one or more of the respective locations in the network traversed by the at least one of the data packets. Information regarding the at least one intercepted packet at the one or more respective locations is recorded and processed to analyze a route of the at least one intercepted packet through the network.

Network packet tracking

A method and apparatus for testing a network having a plurality of nodes. The method includes sending commands to one or more traffic agents connected to the network and to at least one network management agent coupled to a respective node of the network, transmitting data from at least one of the traffic agents over the network responsive to the commands, determining network information at the at least one network management agent responsive to the commands and to transmission of the data through the respective node, and receiving and evaluating the network information to assess a state of the network.

Fault location and performance testing of communication networks

A system for implementing flow control in an information network such as a local area network (LAN) utilizing a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) as specified by the IEEE standard 802.03. The information network transmits computer information such as computer data between various computer systems coupled to the information network. The information network includes information network switches capable of routing information packets received via its input ports to its output ports. The received packets are held in buffers of the output ports before being transmitted via the output ports. A portion of each output port buffer is allocated to each input port. The information network switch provides a control packet such as a PAUSE frame to an upstream source operably coupled to the input port in response to the level occupancy of the portion of the buffer allocated to the input port exceeding a first level. The PAUSE frame inhibits the upstream source from transmitting information packets to the input port. In one system, each up stream source has the capability of ignoring the control packet when the level of occupancy of an output buffer of the upstream source exceeds a threshold level.

Flow control using output port buffer allocation

In a communication network having a set of hosts and switch based label swapping communication nodes, each node has a control processor that is also a host that sends and receives messages via the switching apparatus in its associated node. At least one of the hosts includes a distribution tree set up procedure. That procedure stores source and destination data designating a set of source hosts and a set of destination hosts in the communication network, and defines a distribution tree of virtual connections. The designated source hosts and destination hosts may include the control processors of some or all the network nodes. The defined virtual connections include a virtual connection from each designated source host to all of the designated destination hosts, and message labels for all messages sent by the source hosts to be routed to the destination nodes. The virtual connections convey each message from the source hosts that have the defined message labels to all the designated destination hosts as a single multicast message. The message labels are defined so that overlapping portions of the virtual connections use the same message labels. All the nodes in the distribution tree are programmed by sending one or more virtual connection set up messages that instruct the nodes in the distribution tree on the label swapping data to be stored in each such node.

System for defining multicast message distribution paths having

In a communication network having a set of hosts and switch based label swapping communication nodes, each node has a control processor that is also a host that sends and receives messages via the switching apparatus in its associated node. Each node's control processor also includes a virtual connection (VC) traversal procedure that implements the methodology of the present invention. The control processor of any node along an established connection can initiate the transmission of a VC traversal message to the control processors of all the nodes along the connection. The VC traversal message is transmitted as one or more ATM cells, where each cell includes a standard ATM header for routing the cell to a neighboring node's control processor, as well as a VC traversal header in the body of the cell that identifies the connection being traversed. When a node receives a VC traversal message with a VC traversal header in it, the virtual connection traversal procedure in the receiving node processes that message by (A) performing whatever command is indicated in the VC traversal header, (B) routing a copy of the VC traversal message to the control processor of each node to which a data cell on the connection being traversed would be sent, and (C) performing a VC traversal header swapping operation on each such copy of the VC traversal message so that the VC traversal header in each forwarded VC traversal message identifies the segment of the connection being traversed by the control message.

Growing community of inventors

Haifa, Israel

Moshe Sidi