Binary Schedule Slot Allocation for Deterministic Network Latency
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Solution Overview
Problem
Current networking techniques, such as classical packet network redundancy and overprovisioning, are insufficient for ensuring low loss ratios and latency guarantees in deterministic networks used in critical applications like automotive and industrial systems, as they fail to provide sufficient bandwidth and are inflexible in meeting changing requirements.
Innovation Solution
The method involves flexibly reserving cycle-slots in network nodes using a binary schedule scheme, where each cycle is divided into equally-spaced slots, allowing for customized allocation of slots based on reserved stream requests to guarantee transmission parameters like latency and loss rate, and synchronizing nodes to ensure precise timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical packet network redundancy and overprovisioning techniques are used, then network coverage and basic connectivity are improved, but loss ratio and latency guarantees deteriorate due to insufficient bandwidth and congestion
Solution Approach 1:
The network bandwidth is segmented into discrete time slots organized in a binary tree structure across multiple virtual layers. Each layer divides the cycle into 2^n equally-spaced slots, creating a hierarchical segmentation that allows precise allocation of bandwidth to different streams without congestion
Solution Approach 2:
The system dynamically allocates time slots to streams based on their specific bandwidth requirements and priority levels. The binary schedule allows flexible reconfiguration of slot assignments to adapt to changing network conditions and application needs, providing both guaranteed and best-effort service
2Reliability
If operator-configured or application-requested path redundancy is implemented, then reliability against equipment failure is improved, but congestion losses increase due to correlated losses on different paths
Solution Approach 1:
The patent extracts congestion as a separate problem from reliability considerations by implementing deterministic scheduling that eliminates congestion entirely. The binary schedule guarantees bandwidth allocation for all streams, removing congestion-induced packet loss while maintaining path redundancy for fault tolerance
3Reliability
If weighted queuing and traffic shaping are applied, then some real-time performance is improved, but flexibility and ease of operation deteriorate due to expert knowledge requirements and inflexibility to changing requirements
Solution Approach 1:
The binary schedule provides dynamic flexibility where slot assignments can be easily reconfigured by changing the schedule parameters without requiring expert knowledge. The system adapts to changing requirements by modifying the binary tree structure or slot allocations, making it both simple to operate and highly adaptable
Solution Approach 2:
The system changes the parameter of time slot allocation from fixed weighted proportions to dynamically adjustable binary schedule assignments. This allows straightforward modification of bandwidth distribution by changing schedule parameters rather than reconfiguring complex queuing weights
4Measurement precision
If hardware assist for time synchronization is implemented, then measurement precision is improved to achieve 1 μs level synchronization, but device complexity increases
Solution Approach 1:
The system performs preliminary time synchronization setup during initialization, establishing the binary schedule clocking structure in advance. This preliminary action enables precise timing without requiring continuous complex hardware intervention during normal operation
Data Source
AI summary
A method for allocating port assignments for transmitting a reserved network stream across a network node comprises determining a cycle time associated with a network node. The method also comprises establishing, for at least one port of the network node, a plurality of virtual layers associated with the cycle time, wherein each of the plurality of virtual layers is divided into 2n equally-spaced slots per cycle (where n>0). The method further comprises receiving a reserved stream request associated with transmission of a reserved stream across the node, and determining a number of slots required to transmit the reserved stream. The method also comprises assigning one or more slots associated with a port of the network node to the transmission of packets associated with the reserved stream based on the determined number of slots. The method further comprises transmitting the stream according to the slot assignment associated with the port of the network node.