A network impairment tool based on the IXDP425 network processor.

摘要

The objective of this thesis is to design and develop a network impairment tool. The tool will manipulate incoming packets to generate network faults such as packet loss, delay, duplication and reordering. Network impairment tools are being used widely in both the commercial and academic worlds to verify and stress test network products and systems. The proposed tool can also be used to emulate a large network to form a realistic and controlled verification environment.; The core component of the impairment system is an Intel IXDP425 network processor (a specialized platform optimized for packet processing) evaluation board. The impairment code is developed on top of the application programming interface provided in the IXDP425. This impairment tool has several improvements over existing tools in term of flexibility, robustness, efficiency, and cost. Two impairment emulation modes are supported: model-based and trace-based. The model-based mode has a powerful set of probability models ready to be used; whereas the trace-based mode permits the user to inject packet entries in a manner similar to traffic logging.; The performance tests show that in most cases, the impairment process imposes negligible overhead. Only when the packet size is very small (i.e. the maximum packet rate is high), then the overhead will run up quickly. In such cases, the internal packet queues reach their capacity; hence the waiting time for each packet becomes higher.