Automatic IPv4-Compatible Tunnels
This blazon of adit uses IPv4-compatible IPv6 addresses for the adit interfaces. These addresses
are taken from the ::/96 abode space. That is, the aboriginal 96 $.25 of the adit interface addresses are
all 0s, and the actual 32 $.25 are acquired from an IPv4 address. These addresses are accounting as
0:0:0:0:0:0:A.B.C.D, or ::A.B.C.D, area A.B.C.D represents the IPv4 address.
The adit destination for an IPv4-compatible adit is automatically bent from the loworder
32 $.25 of the adit interface address. To apparatus this adit type, use the command
tunnel approach ipv6ip auto-tunnel in adit interface agreement mode.
IPv4-compatible IPv6 acclamation is not broadly deployed and does not accommodate to accepted global
usage of the IPv6 abode space. Furthermore, this tunneling adjustment does not calibration well.
Therefore, Cisco recommends application ISATAP tunnels instead of this method, and for these reasons,
this book does not analyze this adit blazon further.