H3C Technologies H3C S12500 Series Switches - Manual (Page 141)

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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.
VRRP packets are encapsulated in IP packets, with the protocol number being 112.
Figure 30 shows the
format of an IPv4 VRRPv2 packet. Figure 31 shows the format of an IPv6 VRRPv2 packet. Figure 32 shows
the format of an IPv4/IPv6 VRRPv3 packet.
Figure 30 Format of an IPv4 VRRPv2 packet
Figure 31 Format of an IPv6 VRRPv2 packet
...
Version Type Virtual Rtr ID Priority Count IPv6 Addrs
Auth Type Adver Int Checksum
IPv6 address 1
Authentication data 1
Authentication data 2
IPv6 address n
0 7 15 23 31 3