Load Balancing Fragmented Tunnel Frames via Inner IP Header Reassembly

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Solution Overview

Problem

Conventional load-balancing systems in computer networks struggle with fragmented tunneled traffic, as they lack access to the inner IP header, leading to degraded functionality and improper forwarding of non-first fragments, especially in scenarios where Maximum Transmission Unit (MTU) restrictions are present.

Innovation Solution

A system and method that reassembles fragmented tunnel frames to determine the inner IP header, applies traffic policies based on this header, and inserts metadata into subsequent frames to maintain flow affinity and ensure proper load balancing across network paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If load balancing is performed based on the inner IP header in tunneled connections, then load balancing accuracy is improved, but the system cannot properly handle fragmented packets because the inner IP header is not available on subsequent fragments

Engineering Contradiction:
Improveload balancing accuracyVSAvoidpacket forwarding reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary reassembly of fragmented packets to reconstruct the complete inner IP header before load balancing decisions are made. This preliminary action ensures that the inner IP header information is available for accurate load balancing while maintaining reliable packet forwarding, as the reassembly process recovers the header data that would otherwise be lost in fragmented packets

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If packet fragmentation is used to handle MTU restrictions, then network adaptability is improved, but the inner IP header becomes unavailable on subsequent fragments making load balancing impossible

Engineering Contradiction:
Improvenetwork adaptabilityVSAvoidinner IP header information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The system introduces an intermediary reassembly process that acts as a mediator between fragmented packets and load balancing functions. This intermediary recovers the inner IP header information from fragmented packets by reassembling them, thereby preventing information loss while maintaining network adaptability through fragmentation handling

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If conventional load balancers only recreate the outer IP header on fragmented frames, then processing simplicity is maintained, but functionality is degraded because the full packet information is unavailable

Engineering Contradiction:
Improveprocessing simplicityVSAvoidnetwork function reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary reassembly of fragmented packets to reconstruct the complete inner IP header before load balancing decisions are made. This preliminary action ensures that the inner IP header information is available for accurate load balancing while maintaining reliable packet forwarding, as the reassembly process recovers the header data that would otherwise be lost in fragmented packets

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2928144B1System and method for load balancing in computer networks
Publication Date: 2016.11.02 SANDVINE CORP
  • EP2928144B1 patent drawingFigure 1A~1B
  • EP2928144B1 patent drawingFigure 2A
  • EP2928144B1 patent drawingFigure 2B

AI summary

A method and system for load balancing are provided. The method includes: receiving a tunnel frame from a traffic flow; determining whether the tunnel frame is one of a plurality of frames from a packet; if the frame is one of a plurality of frames, reassembling the plurality of frames associated with the packet to determine an inner IP header; load balancing the packet based on the inner IP header; and applying traffic policies to the packet. The system has: a traffic interface configured to receive a tunnel frame from the traffic flow; a subscriber load balancer configured to determine whether the tunnel frame is one of a plurality of frames from a packet; at least one IP reassembly engine configured to reassemble the plurality of frames associated with the packet to determine an inner IP header; and at least one flow policy engine configured to load balance the packet based on the inner IP header; and apply traffic policies to the packet.