Configuration Guide IPv6 Configuration
3. Site-level Local Addresses
The format of the site-level local addresses is shown as follows:
| 10 |
| bits | 38 bits | 16 bits | 64 bits |
+-------------+----------------+--------------+---------------------------------------+
|1111111011| 0 | subnet ID | interface ID |
+-------------+---------------+-------------+-----------------------------------------+
The site-level local address can be taken to transmit the data within the site, and the
router will not forward the message of the source address of the destination address
with the site-level local address to Internet. Namely, such packet route can only be
forwarded within the site, but cannot be forwarded to out of the site. The former 10-bit
prefix of the site-level local address is slightly different of that of the link-level local
address, whose intermediate 38 bits are 0s, the subnet identifier of the site-level local
address is 16 bits, while the latter 64 bits also indicate the interface identifier, usually
for the EUI-64 address of IEEE.
4. IPv6 of IPv4 Addresses
The RFC2373 also defines 2 types of special IPv6 addresses embedded with IPv4
addresses:
IPv4-compatible IPv6 address
| 80 bits | 16 | 32 bits |
+-----------------------------------------------------+----+----------------------------+
|0000.....................................................0000|0000| IPv4 address |
+------------------------------------------------------+----+---------------------------+
IPv4-mapped IPv6 address
| 80 bits | 16 | 32 bits |
+-----------------------------------------------------+----+---------------------------+
|0000........................................................0000|ffff| IPv4 address |
+-----------------------------------------------------+----+---------------------------+
The IPv4-compatible IPv6 address is mainly used to the automatic tunneling, which
supports both the IPv4 and IPv6. The IPv4-compatible IPv6 address will transmit the
IPv6 packet via the IPv4 router in the tunneling way. The IPv6 address of an IPv4
mapping is used to access the nodes that only support IPv4 by IP6 nodes. For
example, when one IPv6 application of the IPv4/IPv6 host requests the resolution of a
host name (the host only supports IPv4), the name server will internally generate the
To Next Page
Loading...
