Packet Switching Device Path Modulation for Flow Congestion
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Solution Overview
Problem
Current packet switching technologies face challenges in maintaining packet order across multiple paths within a packet switching device, leading to potential congestion and resource inefficiencies due to the need for frequent path switching and reordering of packets.
Innovation Solution
The implementation of a packet switching device with distribution, routing, and egress stage switch elements that assign packet flows to multiple paths based on a distribution period, ensuring packets are sent in order within each path while allowing different paths to be selected for each period, minimizing reordering and resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packets are sent over multiple links to achieve higher communication rates, then bandwidth and capacity are improved, but packet order is lost and reordering complexity increases
Solution Approach 1:
The patent segments packets into different distribution periods, where packets from the same distribution period are guaranteed to arrive in order. This segmentation allows parallel transmission over multiple paths while maintaining order within each segment, resolving the contradiction between high communication rate and reordering complexity.
Solution Approach 2:
The system performs preliminary classification of packets into distribution periods before transmission. By pre-organizing packets with period identifiers and assigning them to specific paths based on their period, the system eliminates the need for complex post-reception reordering, thus improving communication rate while controlling reordering complexity.
2Adaptability or versatility
If path switching is performed frequently to balance load, then resource utilization is improved, but packet order is disrupted and buffering requirements increase
Solution Approach 1:
The patent implements periodic path assignment where the same path is used for all packets within a distribution period. Paths are switched between periods rather than within periods, which maintains packet order while still achieving load balancing across multiple paths over time. This periodic approach reduces buffering delay compared to frequent path switching.
3Reliability
If packets are reordered at egress to maintain flow order, then packet delivery accuracy is improved, but device complexity and memory requirements increase
Solution Approach 1:
Instead of reordering packets at the egress stage after they arrive out of order, the patent inverts the approach by ensuring packets are delivered in order through controlled path assignment and distribution period management. This eliminates the need for complex egress reordering mechanisms while maintaining packet delivery accuracy.
Data Source
AI summary
In one embodiment, for each distribution period of time, each packet flow is assigned to a path through a packet switching device (e.g., switch fabric) with all packets of the packet flow being sent in order over the assigned path. For a next distribution period, different paths are assigned for these packet flows, with all packets being sent in order over the new corresponding selected path. In one embodiment, these paths are switched often enough to prevent congestion, yet infrequent enough so as to minimize resources for reordering. In one embodiment, the reordering is done at the egress and only for predefined high bandwidth flows (e.g., elephant flows). A distribution period indication is typically associated with each packet to identify its corresponding distribution period. In one embodiment, each routing and egress switching stage in a switching fabric performs reordering.