Spirent Communications, Inc.

Jocelyn Kunimitsu

Craig Fujikami

William Thomas Hatley

Carl Uyehara

John K Morris

Jon Kanji Otaguro

Wade Teruya

The disclosed technology teaches techniques for generating a high quantity of internet traffic flows, such as in the form of data packets, to stress test network components by using range variable field modifiers. The techniques generate a large scale of flows at a relatively fast speed by using a process that may involve a finite state machine feedback loop and a multiple range variable field modifier process. Start and end range pointers for range entries of data packet modifiers are stored in memory and used with pointer and counter values, which are varied and updated in a relatively fast feedback loop. Data packet modifiers may be selected based on the pointer and counter values and are used to modify or generate data packets.

Generation of data packets for high speed network testing using range variable field modifiers

The frame sequence table (FST) architecture disclosed here partitions an FST stored in the Block RAM on an FPGA into at least two tables for emulating frame sequences for testing network equipment by providing more accurate emulations of network environments. In some implementations, one FST (the primary FST) provides frame listings for high data rate streams, while the other FST provides low data rate streams (the 'slow' FST, or SFST). Data compression techniques may be used for the primary FST, allowing emulation of high frame rates using multiple repetitions of frames, while the separation of low frequency streams into the SFST (along with residuals from the primary FST), allows them to be represented accurately when mixed into the final data stream in the output port. A “ping-pong” state machine implemented in firmware governs the selection of data streams from the primary FST and SFST into the output data flow.

Dual frame sequence tables for network testing

A disclosed method processes a data feed including multiple streams. The method includes processing n frames of the multiple streams in parallel through n processing pipelines, n being an integer greater than or equal to 2. The n frames include a first frame belonging to a first stream and a second frame belonging to a second stream. The first stream is different than the second stream. The n processing pipelines are coupled to n-by-n value buffers per stream per recorded value for the stream, and at least one status buffer per stream. The n processing pipelines are each assigned a distinct row of read-authorized port access to the n-by-n value buffers and a distinct column of write-authorized port access to the n-by-n value buffers.

Reducing cache memory requirements for recording statistics from testing with a multiplicity of flows

A method is provided for generating errored test message words in network traffic used for testing. The method includes for each error cycle, select an error generator threshold, using a pseudo random sequence generator that advances with a new error cycle. The method includes for each test word generation cycle, determine whether to apply a bit error mask to a generated test word. An accumulator value is accumulated by an increment that takes into account at least a bit error rate and a bus width. The accumulator value is tested against the threshold. Upon reaching the threshold, a bit error mask is selected from a set of bit error masks, and applied to the generated test word. The threshold is then subtracted from the accumulator value, and a new error generator threshold is selected. The generated test word is output with or without a bit error as determined.

Pseudo-random error insertion for network testing

A method reduces a cycle time of an individual memory module to an effective cycle time shorter than the cycle time using a plurality of memory modules having a circular sequence. The method includes initiating a set of read operations on different memory modules of the plurality of memory modules in the circular sequence from a first read operation initiated on a first module of the plurality of memory modules to a last read operation initiated on the second module. After initiating each read operation of the set of read operations on a particular memory module of the plurality of memory modules and prior to initiating a next read operation in the set of read operations, the method initiates a set of write operations to write a same value to all of the plurality of memory modules in the circular sequence beginning one memory module after the particular memory module.

Reducing effective cycle time in accessing memory modules

Embodiments of the invention relate to generating simulated network traffic. In some embodiments, simulated network traffic may be generated using a specification of a sequence of frames to be transmitted from the network testing device. The specification may specify at least two frames including a first frame and a second frame. The specification may further specify a first interframe gap associated with the first frame and a second interframe gap, having a different length from the first interframe gap, associated with the second frame. In some embodiments, the specification may specify an interframe gap for each frame in the sequence of frames. This information may be used to determine the relative transmit time of each frame to be transmitted. Because the specification identifies an interframe gap for each frame in the sequence, in some embodiments, multi-frame burst network traffic may be generated.

Methods and apparatus for generating simulated network traffic

Embodiments of the invention are directed to evaluating the sequence of packets in a received packet stream. In some embodiments, when a packet in the packet stream is received, its sequence number may be determined and compared to an expected sequence number indicative of the highest received sequence number in the packet stream. If the sequence number of the packet is greater than or equal to the expected sequence number, the packet may be considered an in-order packet and a counter that counts the number of received in-order packets in the packet stream may be incremented.

Methods and apparatus for evaluating the sequence of packets

Information is added to an encapsulated payload in a data field of a frame subsequently to placing a checksum into a checksum field of a header encapsulating the payload, wherein the checksum has been determined from byte values of the header and the payload, yet having the checksum remaining detectable as valid upon interpretation of the header and the payload. A signature field that contains the information is inserted into the data field. The signature field has a checksum cheater subfield. A one's complement of a checksum determined from byte values of the information is then placed into the checksum cheater subfield. Accordingly, the checksum in the checksum field of the header remains valid.

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Aiea, HI, United States of America

Jocelyn Kunimitsu