Chapter 39 Device HA

Legacy Mode ZyWALL VRRP Application

In VRRP, a virtual router represents a number of ZyWALLs associated with one IP address, the IP address of the default gateway. Each virtual router is identified by

aunique 8-bit identification number called a Virtual Router ID (VR ID). In the example below, ZyWALL A and ZyWALL B are part of virtual router 10 with IP address 192.168.10.254.

Figure 458 Example: VRRP, Normal Operation

The VR ID is not shown. In normal operation, ZyWALL A is the master. It has the same IP address as the default gateway and forwards traffic for the network. ZyWALL B is a backup. It is using its management IP address 192.168.10.112. ZyWALL A sends regular messages to ZyWALL B to let ZyWALL B know that ZyWALL A is available. If ZyWALL A becomes unavailable, it stops sending messages to ZyWALL B. ZyWALL B detects this and assumes the role of the master. This is illustrated below.

Figure 459 Example: VRRP, Master Becomes Unavailable

192.168.10.112

ZyWALL B is now using the IP address of the default gateway, and it is forwarding packets for the network. The loss of ZyWALL A has no effect on the network.

If there is more than one backup ZyWALL, the backup ZyWALL with the highest priority becomes the master. The other backup ZyWALLs remain backups.

686

 

ZyWALL USG 2000 User’s Guide