VM Migration via /32 Subnets and L3 Routing

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Solution Overview

Problem

The inefficiencies and complexities introduced by ARP calls and L2 extensions in virtual machine migrations across subnets lead to high latency and problematic failure modes due to unsynchronized L2 switches, particularly in data center environments.

Innovation Solution

The method involves assigning each virtual machine a unique /32 or /128 IP address within its own subnet, allowing packet transmission based on Layer 3 routing, thereby eliminating the need for L2 switches and avoiding intra-subnet forwarding, and using a central controller to manage routing tables across routers to facilitate seamless VM migrations between hosts without requiring L2 extensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If L2 extensions are implemented for VM migration across subnets, then VM mobility is improved, but network latency increases and failure modes occur due to unsynchronized L2 switches

Engineering Contradiction:

ImproveVM mobilityVSAvoidnetwork latency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent divides the network into multiple subnets and allows VMs to migrate across these subnets using Layer 3 routing instead of requiring a single extended L2 domain. Each subnet operates independently with its own L2 switching, eliminating the need for complex L2 extension synchronization while maintaining VM mobility through IP-based routing.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If L2 extensions are used for cross-subnet VM migration, then VM mobility is enabled, but system reliability deteriorates due to problematic failure modes from unsynchronized L2 switches

Engineering Contradiction:

Improvecross-subnet migrationVSAvoidnetwork stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces Layer 3 routers as intermediary devices between subnets, replacing the need for L2 extensions. These routers handle packet forwarding between subnets using IP addresses, eliminating the synchronization problems inherent in L2 extensions while maintaining reliable cross-subnet VM migration.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of information

If ARP calls are used for VM location notification within L2 extensions, then forwarding table updates are achieved, but network overhead increases

Engineering Contradiction:

Improveforwarding table accuracyVSAvoidnetwork overhead

Core Design Contradiction:

Loss of informationVSLoss of energy

Solution Approach 1:

The patent replaces the L2 ARP-based location notification mechanism with L3 IP-based routing. Instead of using ARP calls to update switching tables, the system uses IP address routing where routers automatically forward packets based on destination IP addresses, eliminating the overhead of ARP protocols while maintaining accurate packet delivery.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11496436B2Migration of virtual machine located on its own network

Publication Date: 2022.11.08 VMWARE INC

AI summary

The disclosure provides an approach for eliminating issues associated with the use of an L2 extension and ARP calls after migrating a virtual machine from one host to another host. The approach involves placing nodes within a network within their own subnetworks, each subnetwork having an IP address range of one address. Placing nodes into subnets of one avoids intra-subnet forwarding, eliminating the need for ARP calls and for L2 extensions.