Packet Format - 3Com S7906E Configuration Manual

Packet Format

The master multicasts VRRP packets periodically to declare its existence. VRRP packets are also used
for checking the parameters of the virtual router and electing the master.
Figure 1-3 shows the format of a VRRPv2 packet and
Figure 1-3 Format of a VRRPv2 packet
Figure 1-4 Format of a VRRPv3 packet
0 3
Version Type
Auth Type
A VRRP packet consists of the following fields:
Version: Version number of the protocol, 2 for VRRPv2 and 3 for VRRPv3.
Type: Type of the VRRPv2 or VRRPv3 packet. Only one VRRP packet type is present, that is,
VRRP advertisement, which is represented by 1.
Virtual Rtr ID (VRID): Serial number of the virtual router, that is, serial number of the VRRP group.
It ranges from 1 to 255.
Priority: Priority of the router in the VRRP group, in the range 0 to 255. A greater value represents
a higher priority.
Count IP Addrs/Count IPv6 Addrs: Number of virtual IPv4 or IPv6 addresses for the VRRP group. A
VRRP group can have multiple virtual IPv4 or IPv6 addresses.
7 15
Virtual Rtr ID
Adver Int
IPv6 address 1
IPv6 address n
Authentication data 1
Authentication data 2
Figure 1-4 shows the format of a VRRPv3 packet.
23
Priority Count IPv6 Addrs
Checksum
1-5
31