Layer-2 VM Forwarding Using Transit IP Header Rewriting

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Solution Overview

Problem

Existing overlay networks face inefficiencies in inter-VM traffic forwarding due to the overhead of encapsulation and decapsulation operations, which impact network performance and computational resources.

Innovation Solution

Allocate transit IP addresses to VMs, use these addresses to identify VM information, and modify packet headers to facilitate layer-2 forwarding without encapsulation, allowing hosts to reconstruct packets based on transit IP addresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If overlay networks use encapsulation and decapsulation mechanism for inter-VM traffic forwarding, then network segmentation and multi-tenancy are achieved, but network performance deteriorates and computational resources are consumed

Engineering Contradiction:

Improvenetwork segmentation capabilityVSAvoidnetwork forwarding performance

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent extracts the encapsulation header from the packet forwarding process. Instead of performing full encapsulation and decapsulation operations, the system uses an extraction table to directly obtain egress port information from ingress port and destination MAC address, bypassing the traditional encapsulation overhead while maintaining overlay network functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an extraction table as an intermediary data structure between the ingress port/MAC address and egress port determination. This table stores pre-computed mapping relationships, allowing fast lookup and forwarding decisions without performing complex encapsulation operations in real-time

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If overlay networks use encapsulation and decapsulation mechanism for inter-VM traffic forwarding, then virtual private clouds are established, but computational resources are consumed

Engineering Contradiction:

ImproveVPC deployment capabilityVSAvoidcomputational resource usage

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary action by pre-computing and storing the mapping relationships between ingress port, destination MAC address, and egress port in the extraction table during network initialization or configuration phase. This eliminates the need for complex real-time computations during packet forwarding, significantly reducing computational resource consumption

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12549507B2Method and system for efficient layer-2 forwarding between virtual machines

Publication Date: 2026.02.10 NUTANIX INC

AI summary

A computing system is provided that enables efficient layer-2 traffic forwarding. During operation, the computing system can determine that a packet is from a first virtual machine (VM) running on the computing system and destined to a second VM running on a second computing system. The computing system can determine a first transit Internet Protocol (IP) address of a first VM and a second transit IP address of the second VM. The computing system can then modify the packet to replace existing media access control (MAC) addresses in the layer-2 header with MAC addresses of the computing system and the second computing system. The computing system can also modify the packet to replace the source and destination IP addresses in the layer-3 header with the first and second transit IP addresses, respectively. Subsequently, the computing system can determine an egress port based on the modified layer-2 header.