Distributed Gateway VRRP Mode Reduces Control Plane Overhead

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Solution Overview

Problem

The existing Virtual Router Redundancy Protocol (VRRP) increases control plane overhead in distributed network environments, particularly in scenarios with multiple sites and non-static host architectures, leading to router overload and potential looping of control packets.

Innovation Solution

Implementing a distributed gateway VRRP mode where all routers generate virtual router control packets, with only the master router sending them to hosts within its access network, reducing the frequency of control packet generation and eliminating CPU processing, thereby avoiding control plane overhead and router overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all routers generate VRRP control packets in distributed networks, then router overload and control packet looping occur, but if only master router generates control packets, then failover detection speed decreases

Engineering Contradiction:

Improvenetwork stabilityVSAvoidfailover detection speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent segments the control packet generation function by router type. In distributed networks, non-master routers generate control packets only for their local access networks, while master routers handle other networks. This segmentation prevents router overload and control packet looping by ensuring each router generates packets only for networks it actually serves, rather than all routers generating packets for all networks.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by having each router generate VRRP control packets only for the specific access networks it serves, rather than uniformly for all networks. Non-master routers generate packets locally for their attached access networks, while master routers generate packets for other access networks. This localized approach reduces unnecessary control traffic and prevents looping while maintaining adequate failover detection.

Inventive Principle:

Principle #3Local quality

2Speed

If VRRP control packet generation frequency is increased, then failover detection is expedited, but control plane overhead and router processing load increase

Engineering Contradiction:

Improvefailover detection speedVSAvoidcontrol plane overhead

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent segments control packet generation responsibilities to reduce overall overhead. Non-master routers generate control packets only for their local access networks at optimized frequencies, while master routers generate packets for other networks. This segmentation distributes the control plane load across multiple routers rather than concentrating it, reducing individual router processing requirements while maintaining adequate failover detection speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic control packet generation with optimized frequencies. Non-master routers generate VRRP control packets periodically for their local access networks at frequencies tuned to balance failover detection speed with processing overhead. This periodic action allows the system to maintain reliable failover detection while avoiding continuous high-frequency packet generation that would overwhelm router CPUs.

Inventive Principle:

Principle #19Periodic action

3Reliability

If multiple gateway routers are implemented with discovery protocols, then single point of failure is eliminated, but host resource consumption and routing overhead increase

Engineering Contradiction:

Improvegateway redundancyVSAvoidhost resource consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements self-service by having routers autonomously generate and manage VRRP control packets for their local access networks without requiring host involvement in discovery protocols. Non-master routers automatically generate control packets that announce their presence and capability to serve specific access networks, eliminating the need for hosts to run discovery protocols or maintain complex routing tables while providing gateway redundancy.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9525624B2Virtual router redundancy protocol for scalable distributed default routing gateway

Publication Date: 2016.12.20 EXTREME NETWORKS INC

AI summary

A VRRP router group can operate in either a standard VRRP mode or a distributed gateway mode in which all VRRP routers generate VRRP control packets but transmit those packets only to local access network-side hosts. The rate of VRRP control packet generation may be decreased in the distributed gateway mode relative to the standard mode. Moreover, VRRP router CPUs may cease processing of VRRP control packets in the distributed gateway mode.