Ethernet Switch LAG Routing via Packet Encapsulation

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Solution Overview

Problem

Ethernet Link Aggregation Groups (LAGs) are limited by restrictive physical constraints, such as cable reach and inflexibility in managing changing network requirements, leading to unbalanced packet load and limited bandwidth utilization, as they typically require all links to be active with a single route for packet delivery, which restricts the number of links and flexibility in network topology.

Innovation Solution

An Ethernet switch with a data ingress port, multiple egress ports, and interconnected switching elements that encapsulate incoming data packets with routing information, including LAG information for distributing packets across multiple links, allowing dynamic selection of links for optimal bandwidth utilization and flexibility in network configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single route is used for packet delivery in LAG, then packet order is guaranteed, but bandwidth utilization is limited and packet load becomes unbalanced

Engineering Contradiction:
Improvepacket order guaranteeVSAvoidbandwidth utilization
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the LAG into multiple routes (primary and alternate routes) instead of using a single route. This allows packets to be distributed across different physical links while maintaining order within each route, thereby improving bandwidth utilization without completely sacrificing reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic route selection where the system can switch between primary and alternate routes based on link status and load conditions. This dynamic approach allows the LAG to adapt to changing network conditions, balancing packet load across multiple links while maintaining reliable delivery.

Inventive Principle:
Principle #15Dynamics

2Productivity

If all links in LAG are activated, then bandwidth capacity increases, but physical constraints such as cable reach and topology flexibility are violated

Engineering Contradiction:
Improvebandwidth capacityVSAvoidtopology flexibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a logical routing dimension that operates independently of physical link constraints. By implementing virtual routing tables and logical route identification, the system can aggregate more links than physically contiguous, effectively adding a logical dimension to LAG that transcends physical topology limitations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses routing tables and route identification mechanisms as intermediaries between physical links and packet forwarding. This intermediary layer allows the system to manage complex multi-link aggregations without being constrained by direct physical connectivity, enabling greater topology flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If distribution algorithm is based on MAC addresses, then packet load balancing is achieved, but processing time increases due to MAC table access requirements

Engineering Contradiction:
Improvepacket load balancingVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs route determination as part of the encapsulation process before packet forwarding, rather than during packet processing. By pre-calculating and storing route information in routing tables during the encapsulation phase, the system eliminates the need for real-time MAC table access during packet forwarding, thereby reducing processing time while maintaining load balancing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a simplified distribution algorithm that uses only a portion of the available packet header information (such as source or destination IP address) rather than requiring full MAC address table lookups. This partial action approach provides sufficient load balancing while significantly reducing processing overhead.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2596603B1Ethernet switch and method for routing ethernet data packets
Publication Date: 2018.10.03 CRAY UK
  • EP2596603B1 patent drawingFigure 1~2
  • EP2596603B1 patent drawingFigure 3
  • EP2596603B1 patent drawingFigure 4

AI summary

The present invention relates to data switching networks, and, in particular, to link aggregation groups in Ethernet switching networks. A technique is described in which a large number of links in a link aggregation group can be managed.