Router Contention Control for Worst-Case Transmission Delay
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Solution Overview
Problem
Current methods for determining end-to-end worst-case transmission delay in distributed computing networks face complexity and generate over-approximations, and simulation approaches fail to guarantee worst-case values due to incomplete coverage of system configurations.
Innovation Solution
A method that systematically controls contention by specifying and transmitting competing data frames before a target data frame at each router, using arbitration policies like round-robin or absolute priority, to measure exact end-to-end transmission times, ensuring maximum contention and thus worst-case delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analytical computational methods are used to determine WCTT, then end-to-end worst-case transmission time can be calculated, but the computational complexity increases and over-approximations are generated
Solution Approach 1:
The patent creates a copy of the target data frame and uses it to systematically control contention at each router along the path. By injecting competing data frames based on the copy, the system can precisely measure worst-case delay without requiring complex analytical computations, thus reducing computational complexity while maintaining measurement accuracy
Solution Approach 2:
The patent performs preliminary actions by pre-specifying competing data frames at each router before the actual WCTT measurement. This preliminary configuration of contention scenarios eliminates the need for complex real-time computational methods, reducing computational complexity while ensuring accurate worst-case delay measurement
2Device complexity
If simulation or direct observation methods are used to measure transmission times, then implementation is simpler, but worst-case values cannot be guaranteed due to incomplete coverage of system configurations
Solution Approach 1:
The patent implements a feedback mechanism where the system specifies competing data frames at each router based on the target data frame's path information. This systematic feedback-controlled approach ensures all possible contention scenarios are covered, guaranteeing worst-case values while keeping the measurement method relatively simple
Solution Approach 2:
The patent introduces an intermediary mechanism (the copy of the target data frame) that mediates between the simple observation approach and the requirement for complete scenario coverage. This intermediary enables systematic control of contention scenarios, ensuring worst-case guarantees without the complexity of full analytical methods
3Measurement precision
If competing data frames are transmitted prior to the target data frame to maximize contention, then exact worst-case delay values are obtained, but transmission time increases
Solution Approach 1:
The patent applies partial action by selectively transmitting only the necessary competing data frames that are specified at each router along the target data frame's path. This partial contention control achieves exact worst-case delay measurement without unnecessarily increasing transmission time through excessive competing traffic
Data Source
AI summary
The invention relates to a method for transmitting a target data frame (fA) on a path comprising at least one router (R) that has input ports (P1, P2, P3), at least one output port (PS) and an arbitration unit (UA) configured so as to select a data frame from a plurality of data frames each coming from a different input port and competing for transmission by one and the same output port. The method comprises specifying, for each of the access ports of the router, data frames (fB, fC) competing with the target data frame for transmission by a target output port of the router. An end-to-end transmission time of the target data frame on the path is then measured while the arbitration unit selects the competing data frame (fB) before the target data frame (fA) for transmission by the target output port (PS).