Fluke Corporation

Visual Networks Technologies, Inc.

Visual Networks, Inc.

Thomas R Nisbet

John E Hasselkus

James D Ennis, Jr

Matthew A Tucker

Kent Laver

Robert Troutman

James Thomas Menzies

Gordon Brandyburg

R Scott Drysdale

Jeff Kobryn

David E Wheeler, Jr

Kenneth J Rehbehn

Robert C Troutman

Naresh Kumar Kannan

David Wheeler

James D Ennis

An apparatus and method are provided for analyzing traffic on a network by monitoring packets sent between devices on the network and identifying applications occurring between devices on the network based on information derived from monitoring the packets. Techniques are provided to examine header information of the packets, such as information in the header of Internet Protocol (IP) packets, to identify applications that are occurring on the network. In some cases, information about the packet beyond the header information is examined to match a packet to a particular application. Using these techniques, a list is built of all of the applications occurring between devices on the network. Parameters may be generated to track one or more of the response time, latency and traffic volume associated with a particular device on the network.

Methods and apparatus for analyzing and management of application traffic on networks

A data transmission system includes probes connected between end user sites and a data switching network. Each probe is connected to the switching network via an access channel wherein transmission circuits establish paths between the sites through the access channel and switching network. The probes capture and retransmit data traveling between the sites over respective transmission circuits, and can thereby insert service level analysis (SLA) messages into the data traffic in order to actively communicate network performance information to other probes. For each transmission circuit, the probes periodically collect measurements related to one or more network performance metrics, including: round-trip delay (RTD), data delivery ratio (DDR) and network availability. During each SLA measurement cycle, a sequence of SLA messages is exchanged over each transmission circuit, which messages contain data used to determine RTD and DDR. Optionally, the SLA message contents and protocol are designed to allow the SLA messages to be encapsulated in a single, standard data unit of any conventional data transmission protocol, such as an ATM cell. Consequently, the messaging system can be used with any data transmission protocol and in interworked networks without modification of the message data payload. The SLA measurements collected by the probes can be transmitted to a console in communication with the probes for processing, display, and archiving.

Method and apparatus for performing service level analysis of

Measurement of round-trip delay or travel time in a communications network during in-service operation is accomplished by use of two probes, situated at respective points of interest along the communication network, and a processor. The probes receive identifiable data patterns normally transmitted over the communications network and generate a time stamp when each pattern arrives at or leaves the respective point. Each probe further generates a pattern identifier based on the data in the pattern and stores the identifier and time stamp as a pair in a buffer internal to each probe. Once the internal buffer contents exceed a predetermined amount of data, the processor receives the data from the buffers and matches pattern identifiers between the buffers to locate the departure and arrival time stamps of each pattern traveling between the probe points. Thereafter, the processor calculates an average of round-trip delay or travel times based on the departure and arrival time stamps of several patterns traveling in both directions between the probe points.

Method and apparatus for non-intrusive measurement of round trip delay

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Ellicott City, MD, United States of America

Thomas R Nisbet