Passive Virtual Router Redundancy Protocol for High-Density VLANs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing Virtual Router Redundancy Protocol (VRRP) is limited to implementing only 255 VRRP groups per Ethernet VLAN, which restricts the number of virtual router instances that can support redundancy and traffic redirection in Ethernet networks, leading to increased packet loss and downtime during router failures.
Innovation Solution
The implementation of an active VRRP group and one or more passive VRRP groups, where the passive groups mimic the state changes of the active group, allowing for more than 255 VRRP groups per VLAN by reducing VRRP signaling and CPU load, and enabling sub-second traffic redirection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the standard VRRP protocol is used with unique VRRP MAC addresses for each group, then each VRRP group can be independently identified, but the number of VRRP groups is limited to 255 per VLAN
Solution Approach 1:
The patent merges the VRRP group identification function from the MAC address layer to the IP address layer. Instead of using unique VRRP MAC addresses for each group (which limits to 255 groups), the invention allows multiple VRRP groups to share the same VRRP MAC address by assigning them unique IP addresses. This combining approach removes the 255-group limitation while maintaining group distinguishability through IP addresses.
Solution Approach 2:
The VRRP MAC address is made universal by allowing it to serve multiple VRRP groups simultaneously. The same VRRP MAC address can be shared across numerous groups, with each group distinguished by its IP address. This multi-functionality enables the system to support far more than 255 VRRP groups per VLAN, transforming the MAC address from a group-specific identifier to a shared infrastructure component.
2Reliability
If VRRP advertisements are sent for each group to maintain redundancy state, then failover can be detected, but CPU load and signaling overhead increase with more than 255 groups
Solution Approach 1:
The patent merges multiple VRRP group advertisements into a single shared advertisement mechanism. Instead of each group sending separate VRRP advertisements (which would multiply CPU load linearly with group count), the invention allows multiple groups to participate in a shared advertisement process using common multicast addresses. This combining approach maintains failover detection reliability while significantly reducing the per-group signaling overhead and CPU consumption.
3Loss of time
If sub-second traffic redirection is implemented, then packet loss during failover is minimized, but the system complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring backup routers with standby VRRP instances before failures occur. Backup routers continuously monitor and prepare to take over master responsibilities, maintaining pre-established communication channels and state information. This advance preparation eliminates the need for complex real-time negotiation during failover, enabling sub-second traffic redirection while keeping the state transition mechanism relatively simple and deterministic.
Data Source
AI summary
The present invention relates to a pair of routers which implement an active VRRP group and one or more passive VRRP groups wherein the active VRRP group executes the VRRP election protocol and the passive VRRP group(s) do not execute the VRRP election protocol but instead the passive VRRP group(s) mimic the active VRRP group such that when the active VRRP group has a state change then all of it's dependent passive VRRP group(s) will also have the same state change such as becoming a master or a backup.