Packet Forwarding in Dragonfly HPCC Networks
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Solution Overview
Problem
In high-performance computing clusters (HPCCs), excessive hops or loops in packet paths can occur due to congestion on multiple paths, leading to reduced packet sending efficiency in dragonfly networks.
Innovation Solution
A packet sending method where a first network device determines a non-shortest path with at least two inter-group paths and notifies a second network device to send the packet based on a shortest path, which includes only one inter-group path, thereby reducing the number of inter-group paths the packet needs to traverse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-shortest path is selected to avoid congestion, then packet delivery reliability is improved, but the number of hops increases and loops may occur
Solution Approach 1:
The patent introduces a path type indicator as an intermediary element that guides network devices to select appropriate paths. By embedding this indicator in packet headers, devices can follow directed path selections (shortest or non-shortest) without complex real-time decisions, balancing reliability and transmission time efficiently
Solution Approach 2:
The system dynamically adjusts path selection based on congestion status and path type indicators. Network devices adapt their forwarding behavior by checking the path type indicator in received packets and selecting paths accordingly - using shortest paths when available and non-shortest paths when congestion is detected, optimizing both reliability and transmission time
2Productivity
If multiple inter-group paths are used for load balancing, then network throughput is improved, but path complexity and loop risk increase
Solution Approach 1:
The patent performs preliminary path classification by marking packets with path type indicators before transmission. This pre-marking action allows network devices to follow predetermined path selections without complex real-time calculations, reducing path selection complexity while maintaining throughput through load balancing across marked paths
Solution Approach 2:
The patent segments the network path selection into distinct types (shortest path and non-shortest path) with clear indicators for each. This segmentation simplifies device complexity by providing discrete, easily identifiable path categories rather than requiring continuous optimization calculations, enabling efficient load balancing across segmented path types
Data Source
AI summary
A packet sending method includes, after determining to send a packet based on a non-shortest path and determining that a second network device and a first network device on the non-shortest path belong to different groups, the first network device may send the packet to the second network device, and notify the second network device to send the packet based on a shortest path. After receiving the packet, the second network device may send the packet based on the shortest path, and notify another network device on the shortest path to send the packet based on the shortest path. In this way, in a process of sending the packet, after the packet passes through an inter-group path in the non-shortest path, a remaining path is the shortest path for sending the packet to a destination device.