Hi,
At last weeks IPv6 session in Minneapolis, the working group reached a consensus to deprecate the "IPv4-compatible IPv6 address". This email is to verify this consensus on the mailing list and to review the proposed text to deprecate these address in the update to the IPv6 Address Architecture document. A proposed revision of Section 2.5.2 is include below.
Please review and comment.
Thanks, Bob
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2.5.5 IPv6 Addresses with Embedded IPv4 Addresses
Two types of IPv6 addresses are defined that carry an IPv4 address in the low-order 32 bits of the address.
The first, termed an "IPv4-compatible IPv6 address", was defined to assist in the IPv6 transition. These addresses are now deprecated because the current IPv6 transition mechanisms no longer use them.
The format of "IPv4-compatible IPv6 address" is:
| 80 bits | 16 | 32 bits | +--------------------------------------+--------------------------+ |0000..............................0000|0000| IPv4 address | +--------------------------------------+----+---------------------+
Note: The IPv4 address used in the "IPv4-compatible IPv6 address" must be a globally-unique IPv4 unicast address.
New or updated implementations are not required to support this address type. Existing implementations and deployments may continue to use these addresses.
A second type of IPv6 address which holds an embedded IPv4 address is also defined. This address type is used to represent the addresses of IPv4 nodes as IPv6 addresses. This type of address is termed an "IPv4-mapped IPv6 address" and has the format:
| 80 bits | 16 | 32 bits | +--------------------------------------+--------------------------+ |0000..............................0000|FFFF| IPv4 address | +--------------------------------------+----+---------------------+
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