WeOS
5.29.0

# VRRP HowTo

## About

This document provides a basic VRRP use-case, and how it is configured using the CLI.

For an overview of all available configuration settings for VRRP refer to the configuration guide:

- VRRP Configuration Guide

## Introduction

The simplest use case for VRRP involves two redundant physical routers that together constitute a virtual router between two networks, as showcased in Figure 1.

                                       |
                                   .--.-.
                                  ( (    )__
                                 (_,  \ ) ,_)  Network N2
                                   '-'--`--'
                                    |
                  ---------+--------+--------+---------
                           |                 |
    VRRP Setup         .---+---.         .---+---.         VRRP Setup
    instance: 1        |       |         |       |         instance: 1
    vrid: 1            |  R1   |         |  R2   |         vrid: 1
    vaddr: 10.0.0.100  |       | vlan1   |       | vlan1   vaddr: 10.0.0.100
    prio: 100          '---+---'         '---+---'         prio: 50
                           |.1               |.2
                           |                 |
                  --+------+---Network N1----+---------
                    |          10.0.0.0/24
                  .-+--.
                  | H  | route to N2 via 10.0.0.100
                  '----'

Figure 1: A VRRP setup with two routers forming a virtual router setup.

In this case, host H can reach network N2 even though physical router R1 is down. From the perspective of H, there is only one router - the virtual router - and which of the participating physical routers is the master router does not matter. Additional physical routers R3 etc. may also participate in the virtual router to increase redundancy even further; all that is required is that all participating routers R1, R2, R3 etc. run VRRP instances on their N1-facing interfaces, using the same virtual IP address and virtual router ID, and presumably different physical (real) addresses on those same interfaces.

## Configuration

Configure both of the routers to be part of the same virtual router. We want R1 to be the default master router, therefore it needs to be assigned a higher priority.

It is assumed that both routers have two different VLANs configured for each of the networks described in Figure 1.

### Router 1

Configure a VRRP instance:

    R1:/#> configure
    R1:/config/#> router
    R1:/config/router/#> vrrp 1
    Creating new VRRP instance: 1
    R1:/config/router/vrrp-1/#> priority 100
    R1:/config/router/vrrp-1/#> vrid 1
    R1:/config/router/vrrp-1/#> iface vlan1
    R1:/config/router/vrrp-1/#> address 10.0.0.100
    R1:/config/router/vrrp-1/#> leave
    R1:/#>

Notes on the configuration:

- R1 will be part of the virtual router with `vrid` 1.
- The `address` of the virtual router will be 10.0.0.100.
- List for traffic that enters `iface` vlan1.

### Router 2

Configure a VRRP instance:

    R2:/#> configure
    R2:/config/#> router
    R2:/config/router/#> vrrp 1
    Creating new VRRP instance: 1
    R2:/config/router/vrrp-1/#> priority 50
    R2:/config/router/vrrp-1/#> vrid 1
    R2:/config/router/vrrp-1/#> iface vlan1
    R2:/config/router/vrrp-1/#> address 10.0.0.100
    R2:/config/router/vrrp-1/#> leave
    R2:/#>

Notes on the configuration:

- R2 will be part of a the virtual router with `vrid` 1.
- The `address` of the virtual router will be 10.0.0.100.
- Listen for traffic that enters `iface` vlan1.

## Status

The status of the VRRP can be observed on each individual VRRP router.

Router 1:

    R1:/#> show vrrp

    VRRP Instances
    INSTANCE NAME    BASE INTERFACE   VRID ADDRESS         PRIORITY STATE   GROUP
    1                vlan1            1    10.0.0.100      100(100) MASTER  -

Router 2:

    R1:/#> show vrrp

    VRRP Instances
    INSTANCE NAME    BASE INTERFACE   VRID ADDRESS         PRIORITY STATE   GROUP
    1                vlan1            1    10.0.0.100      50(50)   BACKUP  -

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