On 13/01/2017 12:26, Randy Bush wrote:
but i am having a hard time reconciling 2.4.4's insistence on a
mandatory 64-bit uuid in all unicast global addresses with 2.4.0, rfc
6141, widespread operational practice, ... clue bat please.
This was discussed extensively in 6MAN and resulted in RFC7421
"Analysis of the 64-bit Boundary in IPv6 Addressing”. The text in
rfc4291bis is:
For all unicast addresses, except those that start with the binary
value 000, Interface IDs are required to be 64 bits long.
Background on the 64 bit boundary in IPv6 addresses can be found in
[RFC7421].
thanks for the review that the wg came to this decision in conflict with
operational practice and its own statement in 2.4.0. i did read the
documents.
since it is incorrect, ietf last call seems to be the time to fix it.
to be clear, i have no problem with iids being 64-bit. my issue is with
unicast globals being classful in 2.4.4.
RFC7421 (which is Informational) calls out RFC 6164 (not 6141!) as an exception.
To be precise it says:
The de facto length of almost all IPv6 interface identifiers is
therefore 64 bits. The only documented exception is in [RFC6164],
which standardizes 127-bit prefixes for point-to-point links between
routers, among other things, to avoid a loop condition known as the
ping-pong problem.
I would suggest adding a similar exception statement in 4291bis.
Brian