D-Link xStack DGS-3610 Series Configuration Manual page 425

DGS-3610 Series Configuration Guide
be configured on the Area Border Router of an isolated IPv6 network. For each packet, it
automatically builds a tunnel connecting the Area Border Router in another IPv6 network.
The destination address is the IPv4 address of the Area Border Router in the IPv6 network
on the other end. The IPv4 address is extracted from the destination IPv6 address of the
packet. The destination IPv6 address starts with the prefix 2002::/16 in the following form:
Figure 33-2
The 6to4 address is an address for automatic 6to4 tunnel technology. The IPv4 address
embedded in it is usually the global IPv4 address of the site area border router exit. When
the automatic tunnel is built, the address is used as the IPv4 address for tunnel packet
encapsulation. All the routers at the two ends of the 6ot4 tunnel must also support the IPv6
and IPv4 protocol stacks. A 6to4 tunnel is usually configured between Area Border Routers.
For example, the global IPv4 address of the 6to4 site area border router exit is 211.1.1.1
(Indicated as D301:0101 in hex), a subnet number in the site is 1 and the interface identifier
is 2e0:ddff:fee0:e0e1, then the corresponding 6to4 address can be denoted as follows:
2002: D301:0101:1: 2e0:ddff:fee0:e0e1
Caution
Common application models of 6to4 tunnels:
Simple application models

The simplest and most common application of 6to4 tunnels is used to interconnect multiple
IPv6 sites. Each site must have one connection to one of their shared IPv4 networks at least.
This IPv4 network can be the Internetor the internal backbone network of an organization.
Each site must have a unique global IPv4 address. The 6to4 tunnel will use the address to
form the IPv6 prefix of 6to4/48: 2002:IPV4 address/48.
Mixture application models

Based on the application described above, by 6to4 relay devices provided at the edge of a
pure IPv6 network, other 6to4 networks access the pure IPv6 network. The router used to
implement the function is called 6to4 Relay Router.
Intra-site Subnet
IPv4 Address
Number
IPv6 6to4 Address Format
The IPv4 address embedded in the 6to4 address cannot be a private
IPv4 address (for example, the address of the network interface segment
10.0.0.0/8, 172.16.0.0/12 or 192.168.0.0/16) and must be the global IPv4
address.
Chapter 33 IPV6 Tunnel Configuration
Interface Identifier
33-3