Per-flow Queue Management in Deterministic Network Switches
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Solution Overview
Problem
In deterministic networks, the replacement of dedicated serial links with multiplexed connections can result in improper priority allocation to the oldest queued data packet instead of the newest packet, compromising the guaranteed delivery of real-time data within bounded time constraints.
Innovation Solution
Implementing a method in switching devices to prioritize and transmit the newest data packet over the oldest queued packet at deterministic transmit instances, ensuring timely delivery of real-time data by selectively managing per-flow queues and detecting congestion or queuing latency to overwrite queued packets with new ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deterministic transmission allocates priority to the oldest queued data packet, then packet delivery within bounded time is guaranteed, but real-time data integrity is compromised because the newest packet is delayed
Solution Approach 1:
The patent implements dynamic queue management where the switching device can switch between FIFO mode and newest-packet-priority mode based on real-time conditions. When a new packet arrives and the queue is not full, the system dynamically updates the transmit instance to send the newest packet immediately, rather than statically adhering to FIFO ordering. This dynamic adaptation resolves the contradiction between reliability and real-time performance.
Solution Approach 2:
The patent changes the priority parameter of packets in the queue based on their arrival time and the current system state. Instead of fixed priority assignment, the system modifies the transmit instance parameter dynamically - when a new packet arrives, the transmit instance is updated to reflect the newest packet's priority, thereby changing the transmission order parameter to favor real-time data while maintaining bounded delivery guarantees.
2Productivity
If multiplexed connections are used to replace dedicated serial links, then network resource utilization is improved, but priority allocation becomes improper favoring oldest packets over newest packets
Solution Approach 1:
The patent applies different quality rules to different packets within the same queue based on their position and arrival time. Instead of uniform FIFO treatment, the system assigns local quality priorities where the newest packet receives highest priority for transmission. This local differentiation within the multiplexed queue ensures that real-time data requirements are met while maintaining efficient resource utilization through multiplexing.
Solution Approach 2:
The patent performs preliminary detection of new packet arrival before the deterministic transmit instance occurs. When a new packet is detected in the queue, the system proactively updates the transmit instance to prioritize this newest packet. This preliminary action ensures that priority allocation is corrected before transmission, preventing improper priority allocation while maintaining multiplexed connection efficiency.
Data Source
AI summary
In one embodiment, a method comprises: receiving, by a switching device in a deterministic network, a first data packet associated with an identified flow of data packets, and queuing the first data packet for deterministic transmission at a deterministic transmit instance to a next-hop device in the deterministic network; detecting, by the switching device, reception of a newest data packet associated with the identified flow and before the deterministic transmission of the first data packet; and prioritizing for the identified flow, by the switching device, the newest data packet based on deterministically transmitting, at the deterministic transmit instance, the newest data packet instead of the first data packet.