Siemens RX1500 User Manual page 614

Chapter 5
Setup and Configuration
Two or more VRRP instances can be assigned to be in the same VRRP Group, in which case, they can failover
together.
An Example of VRRP Groups
In the next example, both host 1 and host 2 use a gateway of 192.168.3.10. The external side can access the
internal side by gateway 192.168.2.10. VRID_20 and VRID_21 are grouped together. Normally, router 1 will
provide both an internal and external access gateway, as its priority is higher than those on Router 2. When
either the internal or external side of Router 1 becomes inoperative, Router 1 will remove give control of both
192.168.2.10 and 192.168.3.10 gateways to Router 2.
2
4
5
Figure 675: VRRP Group Example
1. Network 2. Remote Router 1
In this example, the remote routers are configured as follows:
Remote Router 1
• VRID_20 Gateway IP: 192.168.2.10
• VRID_20 Priority: 100
• VRID_21 Gateway IP: 192.168.3.10
• VRID_21 Priority: 100
Other VRRP parameters are the Advertisement Interval and Gratuitous ARP Delay. The advertisement interval
is the time between which advertisements are sent. A backup router will assume the role of Master three
advertisement intervals after the Master fails. If a monitored interface goes down, a Master router will immediately
signal an election and allow a Backup router to assume the Master roles.
The router issues a set of gratuitous ARPs when moving between Master and Backup roles. These unsolicited
ARPs teach the hosts and switches in the network of the current MAC address and port associated with the
gateway. The router will issue a second set of ARPs after the time specified by the Gratuitous ARP delay.
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1
192.168.2.2
192.168.3.2
3. Remote Router 2 4. Switch 5. Host 1 6. Host 2
Remote Router 2
• VRID_20 Gateway IP: 192.168.2.10
• VRID_20 Priority: 50
• VRID_21 Gateway IP: 192.168.3.10
• VRID_21 Priority: 50
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192.168.2.3
3
192.168.3.3
4
6
VRRP Terminology