Siemens RX1500 User Manual page 613

RUGGEDCOM ROX II
User Guide
On RX1500 devices with ROX II v2.3 or higher installed, if the router with the highest priority is in a fault state,
the backup VRRP Router can delay its transition to becoming the Master router. The length of the delay is user-
defined.
VRRP can also monitor a specified interface and give up control of a gateway IP to another VRRP Router if that
interface goes down.
An Example of VRRP
In the following example, host 1 uses a gateway of 1.1.1.253 and host 2 uses a gateway of 1.1.1.252. The
1.1.1.253 gateway is provided by VRID 10. In normal practice, router 1 will provide this virtual IP since its priority
for VRID 10 is higher than that of router 2. If router 1 becomes inoperative or if its w1ppp link fails, it will relinquish
control of gateway IP 1.1.1.253 to router 2.
In a similar fashion host 2 can use the VRID 11 gateway address of 1.1.1.252, which will normally be supplied by
router 2.
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4
5
Figure 674: VRRP Example
1. Network 2. Remote Router 1
In this example, the remote routers are configured as follows:
Remote Router 1
• VRID 10 Gateway IP: 1.1.1.253
• VRID 10 Priority: 100
• VRID 10 Monitor Interface: w1ppp
• VRID 11 Gateway IP: 1.1.1.252
• VRID 11 Priority: 50
Traffic from host 1 is sent through router 1, and traffic from host 2 is sent through router 2. A failure of either
router or their WAN link will be recovered by the other router.
Note that both routers can always be reached by the hosts at their real IP addresses.
VRRP Terminology
1
w1ppp
1.1.1.200
3. Remote Router 2
w2ppp
4. Switch 5. Host 1 6. Host 2
Remote Router 2
• VRID 10 Gateway IP: 1.1.1.253
• VRID 10 Priority: 50
• VRID 11 Gateway IP: 1.1.1.252
• VRID 11 Priority: 100
• VRID 11 Monitor Interface: w2ppp
Chapter 5
Setup and Configuration
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1.1.1.201
4
6
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