Router Advertisement Caching and VLAN-Based Forwarding

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Solution Overview

Problem

In networks with multiple Virtual Local Area Networks (VLANs), router advertisements often reach client devices that are not members of the intended VLAN, causing misconfiguration and unnecessary network traffic, especially when many client devices join the network simultaneously, leading to a flood of unsolicited router advertisements.

Innovation Solution

Implementing a caching and forwarding mechanism where network controllers identify the VLAN configuration of access points and transmit router advertisements as multicast or unicast packets based on the number of VLANs supported, ensuring that advertisements reach only the intended VLANs, and caching recent router advertisements to respond to solicitations instead of retransmitting them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If router advertisements are broadcast to all client devices, then all devices can receive router information, but devices not members of the intended VLAN receive unnecessary information causing misconfiguration and network traffic

Engineering Contradiction:

Improveaccuracy of router advertisement deliveryVSAvoidunnecessary network traffic

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The network is segmented into multiple Virtual Local Area Networks (VLANs), and router advertisements are selectively forwarded only to access points belonging to the appropriate VLAN. This segmentation prevents unnecessary broadcast traffic from reaching devices outside the intended VLAN, resolving the contradiction between reliable delivery and energy loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Access points serve as intermediaries between the router and client devices. The network device determines the VLAN configuration of access points and forwards router advertisements only to the appropriate access points, which then relay the information to their associated client devices. This intermediary mechanism ensures accurate delivery while preventing unnecessary traffic propagation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If router advertisements are transmitted to multiple VLANs, then more client devices can receive the information, but client devices not members of the intended VLAN are misconfigured

Engineering Contradiction:

Improvenetwork connectivity establishmentVSAvoidclient device misconfiguration

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Each access point is assigned a specific VLAN affiliation, and router advertisements are forwarded with local quality control - only to access points whose VLAN matches the advertisement's intended VLAN. This ensures that each client device receives router information appropriate for its specific VLAN context, preventing misconfiguration while maintaining productivity.

Inventive Principle:

Principle #3Local quality

3Productivity

If many client devices join the network simultaneously, then network capacity is utilized, but a flood of solicited router advertisements generates excessive network traffic

Engineering Contradiction:

Improveclient device connection rateVSAvoidnetwork traffic volume

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The network device performs preliminary action by determining the VLAN configuration of access points in advance, before router advertisements need to be forwarded. This pre-established knowledge allows the system to efficiently route advertisements only to appropriate access points even when many client devices join simultaneously, maintaining high connection rates while minimizing unnecessary traffic volume.

Inventive Principle:

Principle #10Preliminary action

4Adaptability or versatility

If router advertisements are forwarded to all access points, then all client devices can potentially connect, but devices in wrong VLANs receive incorrect router information

Engineering Contradiction:

Improvenetwork access flexibilityVSAvoidVLAN configuration accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system implements feedback by having the network device continuously determine and update knowledge about access point VLAN configurations. This feedback mechanism ensures that router advertisements are always forwarded to the correct access points based on current network state, maintaining both access flexibility and configuration accuracy simultaneously.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10291526B2Caching and forwarding router advertisements

Publication Date: 2019.05.14 HEWLETT PACKARD ENTERPRISE DEV LP

AI summary

A router advertisement may be received by a network device, and may include router service information corresponding to a service associated with a router on a network. A virtual local area network (VLAN), which may be one of a plurality of VLANs, for receiving the router advertisement may be identified. A VLAN may be associated with one or more client devices. An access point on the network may be identified. The identified access point is associated with a client device that is associated with the identified VLAN. A VLAN configuration for the identified access point is determined, which may include determining the number of VLANs included in the configuration. The router advertisement may be transmitted according to the VLAN configuration of the identified access point. The router advertisement facilitates a connection to the network when the router advertisement is received by the client device.