Intermediate Logical Interfaces in Virtual Distributed Routers

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Solution Overview

Problem

In network virtualization environments, communication between virtual machines across different subnets or segments leads to unnecessary network traffic and increased latency due to the requirement for IP packets to traverse through L3 routers, even when destination VMs are on the same host, degrading application performance.

Innovation Solution

Implementing a logical routing element (LRE) with active and inactive logical interfaces (LIFs) across host machines, using backplane conduits and unique MAC addresses to route traffic locally without relying on shared L3 routers, and segregating traffic between tenants using distinct routing MAC addresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IP packets traverse through L3 routers for communication between VMs in different subnets, then routing functionality is achieved, but network traffic increases and latency increases

Engineering Contradiction:

Improverouting functionalityVSAvoidnetwork traffic

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the L3 routing function by introducing intermediate LIFs that are active in only specific host machines rather than all host machines. This allows routing functionality to be distributed and activated only where needed, reducing unnecessary network traffic while maintaining routing capabilities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses backplane conduits as intermediary mechanisms to forward packets from host machines with inactive LIFs to host machines with active LIFs. This intermediary approach enables traffic to be routed efficiently without requiring all host machines to maintain active routing interfaces, thereby reducing overall network traffic.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If IP packets traverse through L3 routers for communication between VMs in different subnets, then routing functionality is achieved, but latency increases

Engineering Contradiction:

Improverouting functionalityVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

By segmenting the routing function across intermediate LIFs active in specific host machines, the patent enables more localized routing decisions. This reduces the distance packets need to travel through the network, thereby reducing latency while maintaining routing functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backplane conduit acts as an efficient intermediary that directly connects host machines with inactive LIFs to those with active LIFs. This direct connection path reduces the number of routing hops and minimizes latency compared to traditional L3 router traversal.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If LIFs are active in all host machines, then routing coverage is maximized, but resource consumption increases

Engineering Contradiction:

Improverouting coverageVSAvoidresource consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by making LIFs active only in specific host machines where routing is actually needed, rather than uniformly activating them across all host machines. This selective activation reduces resource consumption in host machines where routing is not required while maintaining adequate routing coverage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of activating LIFs in all host machines (excessive action), the patent uses partial action by activating LIFs only in the subset of host machines where routing is necessary. This partial activation reduces resource consumption while still providing sufficient routing coverage for the virtual network.

Inventive Principle:

Principle #16Partial or excessive action

4Reliability

If traffic is routed through shared L3 routers, then network connectivity is established, but throughput decreases

Engineering Contradiction:

Improvenetwork connectivityVSAvoidthroughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments the routing function by introducing intermediate LIFs in specific host machines, which distributes the routing load away from a single shared L3 router. This segmentation reduces the bottleneck effect at shared routers and improves overall throughput while maintaining network connectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backplane conduit serves as an intermediary that enables direct traffic forwarding between host machines with active LIFs, bypassing the need for traffic to traverse through shared L3 routers. This direct forwarding path reduces congestion at shared routers and improves throughput.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12192103B2Intermediate logical interfaces in a virtual distributed router environment

Publication Date: 2025.01.07 VMWARE INC

AI summary

A LRE (logical routing element) that have LIFs that are active in all host machines spanned by the LRE as well as LIFs that are active in only a subset of those spanned host machines is provided. A host machine having an active LIF for a particular L2 segment would perform the L3 routing operations for network traffic related to that L2 segment. A host machine having an inactive LIF for the particular L2 segment would not perform L3 routing operations for the network traffic of the L2 segment.