Mmpp analysis of network traffic using a transition window

Abstract

Data communication in network traffic is modeled in real time and is analyzed using a 2-state Markov modified Poissen process (MMPP). The traffic inter-arrival times for bursty and idle states define a transition window [λ1max, λ2min] represented by the boundary values λ1max max for the inter-arrival time for bursty traffic, and λ2min for the inter-arrival time for idle traffic. Changes in the values of λ1max and λ2min are tracked over time, and the size of the transition window is enlarged or decreased based upon relative changes in these values. If the inter-rival times for the bursty state and the idle state become approximately equal, the model defaults to a single state model. The modeling is applicable to the synchronization of polling and blocking in a low-latency network system. This permits the adoptive selection of poll or block to maximize CPU utilization and interrupt latency.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application is a division of patent application Ser. No. 10 / 417,467, filed Apr. 16, 2003, and is related to the following U.S. patent applications: U.S. Ser. No. 09 / 607,013 filed Jun. 29, 2000, entitled “Method and System for Reducing Latency in Message Passing Systems, now Pat. No. 7,615,005 (Docket No. RPS920000014US1); U.S. Ser. No. 09 / 607,113, filed Jun. 29, 2000, for “Method and System for Predicting Inter-Packet Delays” now abandoned, (Docket No RPS920000017US1); and U.S. Ser. No. 10 / 17,468, filed Apr. 16, 2003, for “Multilevel Analysis of Self-Similar Network Traffic” (Docket No. RPS920030017US1). The content of these cross-referenced applications is hereby incorporated herein by reference.FIELD OF THE INVENTION [0002] This invention relates in general to the field of computer technology, and particularly to systems for the transfer of data. More specifically, the invention relates to the real-time modeling and analys...

AI Technical Summary

Benefits of technology

[0008] Among the advantages of using this transition window are:

[0009] a) the accuracy of the selection; b) the ability to use dynamic algorithms that are adaptive to the workload; and c) the flexibility of the dynamic algorithms to adaptively adjust the burst length (busty state) to satisfy the requirements of the user process. Further advantages of the present invention include, for example, 1) a reduction in system storage requirements, since it is not necessary to store all received packets for further off-line analysis; 2) immediate real-time availability of information from the analysis for administrative and management purposes to identify or alleviate network problems; 3) availability of current usage information when resources, such as memory buffers or communication bandwidth, are otherwise allocated to support specific services; and 4) a reduction of dependency on human intervention, allowing for the fully automated future network management systems.

Problems solved by technology

Packets generally arrive at a point in the network at random intervals resulting in ‘bursts’ of traffic, causing congestion and ‘idle’ periods in which traffic is somewhat more sparse.

A common design problem with this process is the need to determine when the receive data is available at the input buffers.

The method of synchronization used can directly affect the latency of the receive operation and the utilization of the host computer processor.

The synchronization of the user process with the completion of the receive operation at the network interface card (NIC) has the common design problem that it needs to be determined when receive data is available at the input buffers.

One of the mechanisms used for synchronization is interrupts (blocking), but the problem with interrupts is that they can add to the cost of synchronization with excessive latency and CPU utilization.

Therefore, if the message arrival delay exceeds the interrupt time, then the increase in host processor utilization will actually have a negative impact on the performance of the application.

Therefore, two important concerns regarding the performance of the network interconnect are the overall latency of the message communication and the CPU overhead involving the send and receive primitives.

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