Layer 4 Load Balancing Using Inferred Server Load States

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Layer 4 load balancers in data centers lack awareness of instantaneous server load states, leading to suboptimal workload distribution and resource utilization, particularly in heterogeneous virtualized environments with varying server capacities, resulting in overloading or underutilization.

Innovation Solution

Implementing a load balancing strategy that passively learns server processing capacities using network features and Kalman filters to infer instant server loads, utilizing Shortest Expected Delay (SED) scheduling for optimal workload distribution without manual configuration or additional control planes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional layer 4 load balancing is used, then the load balancer operates with simple flow switching, but it lacks awareness of instantaneous server load states leading to suboptimal workload distribution

Engineering Contradiction:
Improveload awarenessVSAvoidload balancing mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The load balancer passively learns server processing capacities and infers instant server loads using network features and Kalman filters without requiring active participation from servers or manual configuration. The system serves itself by automatically adapting to heterogeneous server environments and making intelligent load balancing decisions based on inferred load states.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors network features such as flow durations and uses Kalman filters to infer server load states, creating a feedback loop where the load balancer adapts its decisions based on real-time information about server processing capacities and current loads.

Inventive Principle:
Principle #23Feedback

2Productivity

If manual configuration is used to optimize workload distribution, then resource utilization can be improved, but device complexity and operational overhead increase

Engineering Contradiction:
Improveresource utilizationVSAvoidconfiguration complexity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The load balancer automatically learns server processing capacities and performs optimal workload distribution without manual configuration. The system self-adjusts to heterogeneous server environments by passively monitoring network features and inferring load states, eliminating the need for operator intervention while maximizing resource utilization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically adapts load balancing parameters based on inferred server load states and processing capacities. By continuously adjusting routing decisions based on real-time network features and Kalman filter predictions, the system optimizes resource distribution without static manual configuration.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If heterogeneous servers with varying capacities are deployed, then service flexibility improves, but workload distribution becomes suboptimal without load awareness

Engineering Contradiction:
Improveserver heterogeneityVSAvoidworkload distribution
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The load balancer tailors its routing decisions to the specific characteristics of individual servers by inferring their processing capacities and current loads. Each server is treated with differentiated attention based on its inferred properties, allowing optimal workload distribution across heterogeneous resources rather than uniform treatment.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adapts its load balancing strategy based on real-time inferred server load states and processing capacities. The routing decisions continuously evolve to match the current state of heterogeneous servers, transitioning from static to dynamic workload distribution that responds to changing server conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20260081871A1Layer 4 load aware load balancing
Publication Date: 2026.03.19 CISCO TECHNOLOGY INC
  • US20260081871A1 patent drawing
  • US20260081871A1 patent drawing
  • US20260081871A1 patent drawing

AI summary

Load aware load balancing may be provided. Flow duration data associated with a plurality of flows associated with a plurality of servers may be obtained. Then a plurality of queue lengths respectively associated with the plurality of servers may be obtained. Next, a Shortest Expected Delay (SED) score may be determined for each of the plurality of servers based on the flow duration data and the plurality of queue lengths. A flow may then be assigned to a one of the plurality of servers having the lowest SED score.