IPv6 VRRPv3 Configuration
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number of which is the same with ‖Count IPv6 Addr‖, and the first one of which should be
the virtual IPv6 address of the virtual router.
Fig 60-1 VRRPv3 message
60.1.2
VRRPv3 Working Mechanism
The working mechanism of VRRPv3 is the same with that of VRRPv2, which is
mainly implemented via the interaction of VRRP advertisement messages. It will be briefly
described as follows:
Each VRRP router has a unique ID: VRIP, ranging from 1 to 255. This router has a
unique virtual MAC address outwardly, and the format of which is 00-00-5E-00-02-{VRID}
(the format of virtual MAC address in VRRPv2 is 00-00-5E-00-01-{VRID}). Master router
is in charge of using this MAC address to respond to ND neighbor request (it is ARP
request in VRRPv2). Thus, no matter what switch is made, the terminal devices will get
the same IP and MAC address all the time, reducing the affection that the switch causes
on terminal devices.
There is only one kind of VRRP control message: VRRP advertisement. It uses IP
multicast data packets to encapsulate, and the format of multicast addresses is
FF02:0:0:0:0:0:XXXX:XXXX. In order to keep a consistence with the multicast address in
VRRPv2 (224.0.0.18), the multicast addresses used by VRRPv3 advertisement
messages can be FF02:0:0:0:0:0:0:12, and the advertisement is limited within the same
LAN. Thus, different VRID are guaranteed to be used repeatedly in different networks. In
order to reduce the overheads of network bandwidth, only master routers can send VRRP
advertisement messages regularly. Backup routers will start a new round of VRRP
selection if it hasn
‘t received a VRRP advertisement in 3 advertisement intervals in a row
or if it receives an advertisement with a priority of 0.
In a VRRP router group, the master router is selected according to priority. The range
of priority in VRRP protocol is 0-255. If the IP address of a VRRP router is the same to that