Proxy Server SLA Metrics via HTTP Timestamps
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Solution Overview
Problem
Current systems fail to accurately calculate service level agreement (SLA) metrics for HTTP-based application servers due to the lack of time information for when requests are received by the server, leading to incomplete performance evaluation and potential service failures.
Innovation Solution
A Software-Defined Networking (SDN) controller configures a proxy server to forward requests and responses between a client device and an HTTP server, receiving timestamp information for both the request receipt and response transmission, allowing for the calculation of metrics such as server processing time, round-trip time, and jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional HTTP request-response systems are used without timestamp tracking, then system simplicity is maintained, but SLA metric calculation accuracy deteriorates due to missing time information
Solution Approach 1:
The system performs preliminary actions by having the server embed timestamps in HTTP headers before responses are transmitted. The server records the request receipt time and response transmission time, embedding these timestamps in the response headers before sending them to the client. This preliminary time-stamping action enables accurate SLA metric calculation without requiring complex client-side or network-side timing mechanisms.
Solution Approach 2:
The patent uses HTTP response headers as an intermediary carrier to transmit timing information from the server to the client. Instead of requiring direct time synchronization or complex measurement protocols between client and server, the timing data is embedded in the existing HTTP header structure, which naturally carries information between the two parties. This intermediary approach simplifies the measurement system while maintaining accuracy.
2Reliability
If comprehensive timestamp tracking is implemented, then performance monitoring capability is improved, but information processing overhead increases
Solution Approach 1:
The HTTP response headers serve multiple functions: they carry standard HTTP metadata and simultaneously convey timing information for SLA measurement. By embedding timestamps in the existing header structure rather than creating separate measurement protocols, the system achieves reliable performance monitoring without adding dedicated overhead channels. The same communication infrastructure handles both data transmission and performance measurement.
Solution Approach 2:
The server automatically generates and embeds timestamps in its own response headers without requiring external timing services or client requests for time information. The server uses its internal clock to record request receipt time and response transmission time, then includes these timestamps in the response. This self-service approach eliminates the need for separate timing infrastructure or client-server time synchronization protocols.
3Measurement precision
If server processing time is accurately measured, then service quality assessment is improved, but calculation complexity increases due to multiple time parameters
Solution Approach 1:
The patent extracts server processing time as a distinct, independently measurable metric by using timestamps embedded in HTTP headers. Instead of requiring complex multi-point measurement systems or network protocol modifications, the system extracts the processing time directly from server-generated timestamps in the response headers. This extracted time value represents purely server-side processing duration, separate from network transmission delays.
Solution Approach 2:
The system implements a simplified measurement approach by focusing on extracting server processing time from available timestamp data rather than implementing comprehensive end-to-end performance monitoring. By using partial information (server timestamps in headers) rather than attempting to measure every component of the request-response cycle, the system achieves accurate server performance assessment without the complexity of full-system timing instrumentation.
Data Source
AI summary
A network device includes a memory and one or more processors in communication with the memory. The one or more processors are configured to configure a proxy server to forward a request for data from a client device to a data server and to forward, from the data server to the client device, a response message that is responsive to the request for data. The one or more processors are further configured to receive an indication of a set of header fields for the response message that indicates a first time specifying when the data server received the request for data and a second time specifying when the response message was sent by the data server and generate a metric for a performance of the data server based on the first time and the second time.