Layer-3 Subnet Stretching via Gateway Tunneling

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Solution Overview

Problem

Current methods for stretching subnets across distributed computing environments often rely on layer-2 (L2) communications, which incur high overhead and latency, and layer-3 (L3) hub configurations that increase processing complexity and error risk, limiting efficiency and availability during network migrations.

Innovation Solution

Implementing an exclusive layer-3 (L3) communication method for subnet stretching, utilizing gateway machines to manage IP addresses and tunneling protocols, allowing seamless subnet extension across multiple networks without reconfiguring applications or infrastructure, thereby reducing downtime and processing resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If layer-2 (L2) gateway is used for subnet stretching, then communication continuity is maintained, but communication overhead and latency increase

Engineering Contradiction:
Improvecommunication continuityVSAvoidcommunication latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent introduces gateway machines as intermediaries that operate at layer-3 to forward packets between stretched subnets. These gateways use routing tables and IP addressing to mediate communication, avoiding the overhead of L2 gateway mechanisms while maintaining communication continuity through proper packet forwarding and routing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the layer-2 gateway mechanism with a layer-3 routing-based approach. Instead of using L2 switching and bridging mechanisms, the system uses IP routing, subnet masks, and gateway forwarding, which reduces communication overhead and latency while achieving the same subnet stretching objective.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If layer-3 (L3) hub with subnet mask /32 is used for subnet stretching, then routing is simplified, but processing complexity and error risk increase due to central handler

Engineering Contradiction:
Improverouting configurationVSAvoidcommunication error rate
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the subnet stretching function across multiple distributed gateway machines rather than using a single central L3 hub. Each gateway independently handles routing for its local subnet portion, distributing the processing load and eliminating the single point of failure and bottleneck associated with central handlers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic routing where gateway machines can adaptively update routing tables and forward packets based on current network conditions. This dynamic approach replaces the static, error-prone central handler configuration with flexible, distributed routing decisions that reduce communication errors.

Inventive Principle:
Principle #15Dynamics

3Reliability

If subnet stretching is implemented across multiple distributed computing environments, then application availability is improved, but reconfiguration overhead and downtime increase

Engineering Contradiction:
Improveapplication availabilityVSAvoidreconfiguration downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent establishes routing tables and gateway configurations in advance before migration is needed. Gateway machines are pre-configured with knowledge of stretched subnets and routing paths, allowing applications to be migrated between environments without reconfiguration downtime since the networking infrastructure is already prepared.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a universal subnet stretching mechanism that works across different distributed computing environments (cloud, on-premises, hybrid) using standard IP routing principles. This universal approach allows applications to maintain the same network configuration regardless of deployment location, eliminating reconfiguration overhead during migrations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If layer-2 (L2) communications are used for subnet stretching, then broadcast and multicast functionality is maintained, but overhead and performance degradation occur

Engineering Contradiction:
Improvebroadcast functionalityVSAvoidcommunication efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent replaces L2 broadcast and multicast mechanisms with L3 routing-based solutions. Instead of relying on L2 switching for broadcast functionality, the system uses L3 routing with appropriate routing table entries to achieve similar communication patterns, thereby eliminating L2 overhead while maintaining adaptability for various communication types.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3466037B1Subnet stretching via layer three communications
Publication Date: 2024.04.24 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3466037B1 patent drawingFigure 1A
  • EP3466037B1 patent drawingFigure 1B
  • EP3466037B1 patent drawingFigure 1C

AI summary

Systems and methods for stretching a subnet that do not require level 2 (L2) communications to be handled are provided. A user may gradually migrate VMs or applications instead of migrating an entire subnet at one time, may fail-over specific VMs without failing-over an entire subnet or renumbering IP addresses, may deploy applications to the cloud without the need to create a VPN, or may enable hybrid network connectivity without modifying routes or (re)configuring edge routers, among other benefits. The domains over which the subnet are stretched include a virtual gateway which is associated with the layer-3 (L3) addresses of the other domains. L3 communications within the domain are routed within that domain, and L3 communications within the subnet in another domain are intercepted by the local gateway, are passed to the remote gateway of the other domain, and are forwarded to the destination while leveraging L3 communications.