Deadline Stack for Time-Sensitive Network Latency
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Solution Overview
Problem
Current Time Sensitive Networking (TSN) mechanisms face challenges in reducing end-to-end propagation latency while maintaining efficiency, as they reserve time durations even for few packets, leading to inefficiencies and high computational costs in calculating optimal gating schedules for large networks.
Innovation Solution
The proposed solution involves inserting a deadline stack into packet headers, where each deadline corresponds to a router in the packet's path, allowing routers to schedule packet transmission based on these deadlines, ensuring timely forwarding and reducing waiting times in output queues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If statistical multiplexing is used in packet-switched networks, then network efficiency is improved with low management overhead, but end-to-end propagation latency increases significantly due to packet queuing
Solution Approach 1:
The patent segments the network traffic into time-sensitive and non-time-sensitive packets, applying different handling mechanisms. Time-sensitive packets are assigned dedicated transmission opportunities through deadline-based scheduling, while other packets continue to use statistical multiplexing, thus resolving the contradiction between efficiency and latency for different traffic types
Solution Approach 2:
The patent introduces deadline values as a new parameter in packet headers to control transmission timing. By dynamically setting and enforcing deadlines for time-sensitive packets, the system can guarantee latency bounds while maintaining statistical multiplexing for the overall network, thus resolving the latency-efficiency tradeoff
2Loss of time
If TSN mechanisms reserve time durations for time-sensitive packets, then latency is reduced, but network efficiency decreases when few packets are transmitted
Solution Approach 1:
The patent implements dynamic deadline assignment where each time-sensitive packet is given a specific deadline value based on its delay budget and current network conditions. This dynamic approach allows the system to provide latency guarantees only when needed (for time-sensitive packets) while allowing statistical multiplexing to operate efficiently for other packets, thus resolving the efficiency-latency contradiction
Solution Approach 2:
Time-sensitive packets carry their own deadline information in the header, enabling them to self-identify and self-prioritize without requiring complex centralized scheduling. The deadline field acts as a self-service mechanism that automatically triggers appropriate handling, eliminating the need for TSN's complex gating schedule calculations while maintaining latency guarantees
3Reliability
If optimal gating schedules are calculated for large networks, then latency guarantees are achieved, but computational costs become excessively high
Solution Approach 1:
The patent extracts the timing guarantee mechanism from the complex TSN gating schedule calculation and implements it through simple deadline values embedded in packet headers. This extraction eliminates the need for centralized schedule calculation and distribution across the network, achieving latency guarantees with minimal computational overhead at each router
Solution Approach 2:
The patent uses simple deadline values (cheap data structures) in packet headers instead of complex gating schedules. These deadline values are computed once at the ingress and then simply decremented or compared at each hop, providing reliable latency guarantees through computationally inexpensive operations that scale to large networks
Data Source
AI summary
Provided herein is a method for a router to process time-sensitive packets, the method comprising: receiving a time-sensitive packet comprising a stack containing at least one local deadline, the stack being comprised within a header of the time-sensitive packet; retrieving a local deadline from the at least one local deadline comprised within the header; and scheduling transmission of the time-sensitive packet based on the local deadline. Also provided is a method for a router to process time-sensitive packets, the method comprising: receiving a time-sensitive packet comprising a stack containing at least one entry, each entry of the at least one entry respectively comprising, as sub-entries, a forwarding instruction and a local deadline; retrieving an entry from the stack; forwarding the time-sensitive packet according to the forwarding instruction comprised in the retrieved entry; and scheduling transmission of the time-sensitive packet based on the local deadline comprised in the retrieved entry.