Mesh Network Node Packet Delay for Deterministic Latency
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Solution Overview
Problem
Conventional communication systems face challenges in meeting stringent latency requirements for Ultra-Low Latency Reliable Communication (ULLRC) and Cloud Radio Access Network (C-RAN) due to nondeterministic latency introduced by shared protection mechanisms in mesh networks, which can result in packet loss during link failures and failure discovery times.
Innovation Solution
The solution involves selectively delaying packets by specific time intervals based on failure detection in mesh networks, using queues to manage packets and route them along either working or backup paths, ensuring deterministic latency and preventing packet loss by determining delay times corresponding to maximum failure detection and propagation times along different paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shared protection mechanisms are used in mesh networks, then reliability is improved through backup paths, but nondeterministic latency is introduced causing packet loss during link failures
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing delay values for different failure scenarios before actual failures occur. The network device pre-determines the appropriate delay to apply when switching from a first path to a second path, eliminating the need for real-time latency calculation during failures. This ensures deterministic latency bounds are maintained while providing reliable backup path switching.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting packet transmission timing based on detected failure conditions. The network device monitors for path failures and dynamically applies pre-calculated delay values to packets being switched to backup paths. This dynamic adjustment ensures that latency remains within deterministic bounds while maintaining reliability through automatic failover.
2Productivity
If packets are transmitted without delay during link failures, then productivity is maintained, but packet loss occurs due to failure detection time
Solution Approach 1:
The patent uses preliminary action by pre-calculating the exact delay needed to bridge the failure detection gap. Instead of reacting to failures after they occur, the system pre-determines the appropriate delay value that accounts for failure detection time and path switching time. This allows packets to be temporarily held and then released after confirmation of failure, preventing packet loss while minimizing impact on productivity.
Solution Approach 2:
The patent applies beforehand cushioning by introducing a controlled delay buffer before packets are transmitted on backup paths. This cushioning delay ensures that packets are not lost during the transition period when a failure is detected but the backup path is not yet active. The pre-calculated delay acts as a protective buffer that absorbs the timing mismatch between failure detection and path switching.
3Loss of time
If deterministic latency is enforced through packet delay, then latency requirements are met, but device complexity increases due to queue management
Solution Approach 1:
The patent applies parameter changes by transforming the latency control problem from a complex real-time scheduling issue into a simple parameter lookup and application task. Instead of implementing complex queue management algorithms, the system changes the approach to using pre-calculated delay parameters that are stored and applied based on failure conditions. This dramatically reduces device complexity while maintaining deterministic latency guarantees.
Solution Approach 2:
The patent uses copying by creating pre-calculated delay value copies for different failure scenarios. Rather than computing delays in real-time, the system creates copies of delay parameters beforehand for various path failure conditions. During operation, the appropriate copied delay value is simply retrieved and applied, avoiding complex real-time calculations and reducing device complexity.
Data Source
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AI summary
A node in a mesh network includes insertion circuitry to selectively delay first packets prior to insertion in a mesh network by a first time interval corresponding to a maximum failure detection time interval for the mesh network based on whether a failure has been detected in the mesh network. The node includes reception circuitry configured to selectively delay second packets received from the mesh network by a second time interval depending on whether the failure has been detected. The second time interval equals a maximum latency for the mesh network minus a sum of the maximum failure detection time interval and a propagation time along a working path. If a failure is detected, the second packets are delayed by a third time interval determined based on the maximum latency, the maximum failure detection time interval, and a propagation time along a backup path for the working path.