ZyXEL Communications ZyWALL 1000 User Manual

ZyWALL USG 1000 User’s Guide

Use device HA and Virtual Router Redundancy Protocol (VRRP) to increase network 
reliability. See 

 for related information on these screens.

Every computer on a network may send packets to a default gateway, which can become a 
single point of failure. Virtual Router Redundancy Protocol (VRRP) allows you to create 
redundant backup gateways to ensure that the default gateway is always available.

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The ZyWALL runs VRRP v2. You can only set up device HA with other 
ZyWALLs of the same model running the same firmware version.

In VRRP, a virtual router represents a number of routers associated with one IP address, the IP 
address of the default gateway. Each virtual router is identified by a unique 8-bit identification 
number called a Virtual Router ID (VR ID). In the example below, Router A and Router B are 
part of virtual router 10 with IP address 192.168.10.254.

Figure 363   Example: VRRP, Normal Operation

The VR ID is not shown. In normal operation, Router A is the master router. It has the same IP 
address as the default gateway and forwards traffic for the network. Router B is a backup 
router. It is using its management IP address 192.168.10.112. Router A sends regular 
messages to Router B to let Router B know that Router A is available. The time interval 
between these messages is called the advertisement interval.