Billion BiPAC 7800(N)X(L) User Manual page 154

Associated WAN Interface: The applied WAN interface with the set tunnel, thus when there are
packets from/to the WAN interface, the tunnel would be used to transport the packets.
Associated LAN Interface: Set the linked LAN interface with the tunnel.
Method: 6rd operation mechanism: manually configured or automatically configured. If manually,
please fill out the following 6rd parameters.
V4 Common Bit Length: Specify the length of IPv4 address carried in IPv6 prefix, for example, 0
means to carry all the 32 bits of IPv4 address while 8 carries 24 bits of the IPv4 address.
6rd Prefix with Prefix Length: Enter the 6rd prefix and prefix length you uniquely designate to 6rd
by the ISP( The 6rd prefix and prefix length are to replace the standard 6to4 prefix 2002::/16 by an
IPv6 prefix that belongs to the ISP-assigned.)
Border Relay IPv4 Address: The IPv4 address of the border relay. The relay is used to unwrap
capsulated IPv4 packets into IPv6 packets and send them to the IPv6 network.
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