Stateful Network Traffic Tester Using FPGA Virtualization
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Solution Overview
Problem
Current network testing equipment struggles to realistically emulate network traffic and volume, particularly in simulating events like TCP segment retransmission and timeouts, and is often prohibitively expensive when scaled to larger networks.
Innovation Solution
A scalable network tester using field programmable gate arrays (FPGAs) to generate and measure stateful network traffic according to the TCP standard, capable of retransmitting unacknowledged segments and managing timeouts, with hardware circuitry that can be cost-effectively expanded by adding state memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple processors are used to emulate network conditions, then the realism of network performance emulation is improved, but the system cost increases prohibitively
Solution Approach 1:
The patent combines multiple processor functions into a single processor by implementing a virtualized architecture where one physical processor emulates multiple subscriber processors through software-based virtual machines. This merging approach maintains the realism of multi-processor network performance emulation while significantly reducing hardware costs and system complexity.
Solution Approach 2:
The patent creates virtual copies of processor functions through software-based virtual machines that replicate subscriber processor behavior. Instead of using multiple physical processors, the system uses software to copy and simulate processor functionality, achieving realistic network emulation at lower cost.
2Productivity
If packet blasting test equipment is used, then the network traffic volume is improved, but the realism of network performance events (TCP retransmission and timeouts) deteriorates
Solution Approach 1:
The patent implements dynamic traffic generation that adapts to network conditions in real-time. The test equipment dynamically adjusts traffic patterns, simulates TCP retransmissions, and responds to network events realistically, rather than using static packet blasting. This allows high traffic volume generation while maintaining realistic network performance characteristics.
Solution Approach 2:
The system incorporates feedback mechanisms where the test equipment monitors network responses and adjusts traffic generation accordingly. It simulates TCP acknowledgments, retransmissions, and timeouts based on actual network conditions, creating realistic feedback loops that packet blasting equipment cannot provide.
3Ease of manufacture
If a single processor emulates multiple subscriber processors, then the system cost is reduced, but the deterministic emulation of multiple processors deteriorates
Solution Approach 1:
The patent segments the emulation functionality into separate virtual machines, each handling specific subscriber processor tasks. This segmentation allows a single physical processor to deterministically emulate multiple processors by dividing work into isolated, time-sliced virtual environments, maintaining deterministic behavior through structured partitioning.
Solution Approach 2:
The system uses periodic time-slicing to allocate processor time to different virtual machines in a deterministic manner. Each virtual machine receives guaranteed CPU time slots in a periodic cycle, ensuring deterministic emulation of multiple processors while running on single hardware.
Data Source
AI summary
A method and apparatus for testing network devices maintains state data in a memory corresponding to a current status for each one of a plurality of connections. Received and transmitted segment identifiers relate each received segment to one of the connections. Each received and transmitted segment is processed and advanced according to a TCP standard and the state data for each segment is updated in the memory. Statistics are collected for each segment as they are processed.