On 17 February 2017 at 07:31, Randy Bush <randy(_at_)psg(_dot_)com> wrote:
What I think we need is to make it clear that there are real
exceptions to 64, and it is therefore not acceptable to embed 64 in
code.
close. 64 is the exception; so slaac can work.
hiding the steaming classful pile in cute places around the document
only gets folk more annoyed.
So what is your objection to having a well-known addressing structure?
Objecting to it, calling it "classful", is implying that it is exactly
the same as IPv4 classful addressing. I don't think IPv6 is.
My memory of classful IPv4 addressing is that it not only specified an
addressing structure, it also specified a forwarding method based on
that structure. (e.g., the default route was only used if there
weren't any routes in the table that had the class matching the class
of the destination address.)
IPv6 doesn't. The addressing structure doesn't specify how different
bits are used during forwarding - all 128 are, using a longest match
per BCP 198.
So IPv6 specifically separates the addressing structure from the
forwarding method. I think calling that "classful" is
mischaracterising it.
Regards,
Mark.
randy
--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6(_at_)ietf(_dot_)org
Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------