[6bed4-devel] Interface identifiers

[<ebi...@xm...>]

I would really appreciate being able to tell a 6bed4 address when I see
one.  Let me recommend using the format:

::64bd:PP:II:II

Having the port and the ipv4 address being contiguous should make it
easier for software to process.

Putting the ipv4 address in the bottom most bits allows address to be
written like ::64bd:8080:12.34.56.78 to instead of their more typical
ipv6 form of ::64bd:8080:0c22:384e

Using a well known value 64bd makes these 6bed4 addresess easy to spot
from a mile away, and it makes it clear these are not MAC48 identifiers
mapped into EUI64 identifiers.

The leading value of 64bd also has the nice property that it leaves the
interface identifer in modified EUI-64 format and has the u and g bits
clear indicating it is not assigned by IEEE aka universally unique and
not a multicast group address.

Also having the magic number in the highest bits of the address makes
these addresses a clear subset of the addresses on a normal lan so you
could if you choose overlap 6bed4 addresses and addresses from other
sources in the same /64.

Eric