Vrrp Terminology - Siemens RUGGEDCOM ROX II User Manual

Chapter 5
Setup and Configuration
If the Master (or, optionally, a condition) fails, the alternate (or backup) routers in the group elect a new Master.
The new master owns the virtual IP address and issues a gratuitous ARP to inform the network of where the
gateway can be reached.
Since the host's default route and MAC address does not change, packet loss at the hosts is limited to the
amount of time required to elect a new router.
Section 5.27.1.2

VRRP Terminology

Each physical router running VRRP is known as a VRRP Router. Two or more VRRP Routers can be configured
to form a Virtual Router. Each VRRP Router may participate in one or more Virtual Routers.
Each Virtual Router has a user-configured Virtual Router Identifier (VRID) and a Virtual IP address or set of IP
addresses on the shared LAN. Hosts on the shared LAN are configured to use these addresses as the default
gateway.
Each router in the Virtual Router Group has a specific priority, which is a number between 1 and 255. The router
with the highest priority (or highest number) is elected the Master, while all other routers are considered Backups.
On RUGGEDCOM RX1500/RX1501/RX1510/RX1511/RX1512 devices with RUGGEDCOM 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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RUGGEDCOM ROX II
CLI User Guide
VRRP Terminology