Resilient Hash Computation for Network Switch Load Balancing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In network switching, existing hash functions fail to effectively handle the scenario where a network interface becomes inoperable, leading to disruptions in packet transmission across multiple links, as they do not adapt to changing interface availability.

Innovation Solution

A network device employs a load balancing network interface selector that uses a first hash function to select network interfaces for packet egress and, upon detecting an inoperable interface, switches to a second hash function to ensure continuous operation by reselecting available interfaces within the group.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single hash function is used to select network interfaces for packet egress, then the system is simple to operate, but the system fails to adapt when a network interface becomes inoperable

Engineering Contradiction:

Improveadaptability to interface failureVSAvoidhash function management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system pre-configures multiple hash functions (first hash function and second hash function) before operation. When interface failure occurs, the system switches to a pre-prepared second hash function that excludes the failed interface from selection, enabling rapid adaptation without complex real-time calculations or system reconfiguration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the hash function parameter (switching from first hash function to second hash function) in response to interface failure conditions. This parameter change allows the system to adapt to new network states while maintaining the same overall load balancing mechanism, resolving the contradiction between adaptability and complexity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the hash function continues to select the inoperable interface, then the hash function maintains consistency, but packet transmission is disrupted

Engineering Contradiction:

Improvepacket transmission reliabilityVSAvoidautomatic failure handling

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system implements feedback by monitoring network interface status and automatically detecting when an interface becomes inoperable. This feedback mechanism triggers the switch from the first hash function to the second hash function, ensuring reliable packet transmission without requiring manual intervention while maintaining automatic failure handling

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The second hash function acts as an intermediary solution between the hash function selection mechanism and the failed network interface. It mediates the conflict by providing an alternative selection mechanism that automatically excludes the failed interface, ensuring reliable transmission while maintaining ease of operation through automatic switching

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple hash functions are maintained for different failure scenarios, then the system achieves high reliability, but the device complexity increases

Engineering Contradiction:

Improvenetwork operation continuityVSAvoidmultiple hash function management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the hash function selection process into distinct functions: the first hash function handles normal operation, while the second hash function handles failure scenarios. This segmentation allows each function to be optimized for its specific purpose, achieving high reliability through specialized handling while managing complexity by keeping each segment relatively simple and well-defined

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9906592B1Resilient hash computation for load balancing in network switches

Publication Date: 2018.02.27 MARVELL ISRAEL (M L S L) LTD

AI summary

A network device includes a packet processor device that determines that packets are to be transmitted via a group of network interfaces, and a load balancing network interface selector. The load balancing network interface selector selects network interfaces in the group via which to egress packets from the network device using a first hash function. In response to determining that a first network interface within the group has become inoperable, the load balancing network interface selector continues to use the first hash function to select network interfaces in the group via which to egress packets from the network device. In response to determining that the first network interface within the group has become inoperable and when the first network interface is selected for packets using the first hash function, the load balancing load balancing network interface selector reselects network interfaces in the group using a second hash function.