Data processing: speech signal processing – linguistics – language – Linguistics – Translation machine
Reexamination Certificate
1998-10-01
2001-07-31
Decady, Albert (Department: 2133)
Data processing: speech signal processing, linguistics, language
Linguistics
Translation machine
C370S248000, C709S224000, C709S225000, C714S712000
Reexamination Certificate
active
06269330
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to communication networks, and specifically to testing and fault discovery in communication networks.
BACKGROUND OF TEE INVENTION
Communication networks are in wide use in many technological fields including distributed computing, data exchange and telecommunication applications. Communication networks generally include a plurality of nodes, such as bridges, LAN switches, routers, cross-connections and telephone switches. The networks further include communication links, such as cables, point-to-point radio connections and optical fibers, which connect the nodes. The networks also include ports, generally within some of the nodes, for attaching external devices such as computers, terminals, handsets, and multiplexers referred to as end-points (or hosts).
Networks are becoming increasingly complex, especially due to their increasing speeds of operation, the number of units interconnected by a network and the formation of large networks from different types of sub-networks. In addition, the networks may transmit concurrently various types of data such as text, voice, video and other multimedia files. In order to allow for these different types of data, some networks are designed to provide different amounts of bandwidth and different levels of quality of service.
A major issue with newly deployed and existing communication networks is testing and trouble-shooting, i.e., checking whether the network is operating according to its specifications and, if not, determining the cause of the network's inadequate performance (for example, the identity of a faulty unit).
Simulators such as “BONeS,” produced by Cadence, San Jose, Calif., and “OPNET,” produced by MIL3, Washington, D.C., allow creation of models of a network, and subsequent testing of the network based on these models. An operator provides the simulator with a map of the network, which includes its components, specifications and expected data traffic patterns. The simulator provides performance estimations of the entire network, together with performance estimations of the network under various constraints, such as a non-operating node or link. Such performance estimation under constraints is referred to as “what-if” analysis. However, simulators do not usually cover all aspects of the simulated networks and are limited in the network size which may be simulated. In addition, simulators are able to detect only design faults, not operational faults.
Application performance measurement tools, such as “Chariot,” produced by Ganymede, Research Triangle Park, N.C., and “Webload” and “Webexam,” produced by Radview, Tel Aviv, Israel, evaluate the performance of existing or new applications as they are introduced into the network. However, they do not test the network itself independent of specific applications. In addition, they do not provide “what-if” analysis capabilities.
Dedicated point-to-point testing equipment is a commonly-used network testing tool. Such equipment is described, for example in U.S. Pat. No. 5,477,531, which is incorporated herein by reference. Usually, dedicated point-to-point testing equipment requires two users who coordinate their operations in order to identify a misbehaving component of the network. Moreover, to test a large network, the testing equipment must be moved between many ports of the network.
Passive network monitoring devices based on network management software, such as “HP-OpenView,” produced by Hewlett Packard, Palo Alto, Calif., and “Soltice Enterprise Manager,” produced by Sun Microsystems, Mountain View, Calif., are also in very common use. These devices are used in network troubleshooting, but they are passive and cannot test a network which is not in use.
SUMMARY OF THE INVENTION
It is an object of some aspects of the present invention to provide methods and apparatus for locating faults within communication networks.
It is another object of some aspects of the present invention to provide methods and apparatus for evaluation of the performance of communication networks.
It is yet another object of some aspects of the present invention to provide methods and apparatus for automatic detection of faults in a communication network.
It is still another object of some aspects of the present invention to provide methods and apparatus for systematic evaluation of the performance of a communication network.
It is still another object of some aspects of the present invention to provide methods and apparatus for evaluation of the performance of a communication network from a single central site.
In preferred embodiments of the present invention, a distributed testing system for evaluating and/or testing a communication network comprises a plurality of traffic agents coupled to nodes and/or hosts of the network. The traffic agents act as artificial users of the network by, for example, transmitting and receiving packets of data, establishing connections, and determining traffic statistics. The testing system further comprises one or more network management (NM) agents coupled to nodes (and possibly to hosts) of the network, which provide information on the interior state of the network. The network management agents preferably monitor the state of the node to which they are coupled, and monitor and possibly copy the traffic that passes through the node. The network management agents preferably also accept commands to configure the node to which they are coupled in terms of its communication abilities.
The testing system further comprises a testing center which conducts tests of the network. The testing center controls the operations of the traffic agents and NM agents by sending them commands or groups of commands, referred to herein as subscripts. In response to the commands, the traffic agents and/or NM agents perform actions and generate reports relating to the network and the traffic therethrough and send the reports to the testing center. The testing center uses the reports from the agents to determine additional tests to be performed and/or to evaluate the state of the network and generate test results which are provided to an operator. Preferably, the testing center stores a plurality of pre-written sets of instructions, referred to herein as scripts, each of which is directed to conduct a specific test session.
The distributed testing system of the present invention provides an operator with the ability to perform a large range of tests on the communication network from substantially any location, by simply connecting to the testing center and invoking one or more scripts at the testing center. Interacting solely with the testing center, the operator may initiate network-wide tests which include transmitting data over the network from various points of the network, and determining the behavior of the generated data and/or other data. Thus, the testing center and/or the operator may detect faults in the network and/or evaluate the performance of the network, based on reports received from agents which are preferably distributed throughout the network.
The stored test scripts allow systematic testing of the network according to stored tests which are prepared for various scenarios. The test scripts include sequences of software instructions written in a scripting programming language, such as Tcl, Javascript or Perl. The test scripts include the subscripts and/or commands to be sent to the traffic agents and NM agents together with control instructions which indicate for example, execution times and conditions of instructions of the script.
Preferably, some scripts invoke by reference other scripts, so that smaller scripts may be used as building blocks to create larger scripts. An operator attempting to find a new type of fault in the network may use a set of existing scripts to perform a more complex test session which will find the fault. Preferably, the testing center records the instructions and scripts invoked by the operator, in order to compose additional scripts which may be used at a later time by the operator
Cidon Israel
Sidi Moshe
Attune Networks Ltd.
De'cady Albert
Flisler Dubb Meyer & Lovejoy LLP
Lamarre Guy
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