On 2007-07-06 02:59, Stephen Sprunk wrote:
...
Why would you ever change PI space? The issue is changing PA space, and
that's something that may need to be done every few weeks as upstream
links go up and down.
Absolutely not. If you have 3 ISPs you run 3 PA prefixes all the time.
If you drop or add an ISP you drop or add a prefix in a planned manner.
RFC 4192.
Compare to the cost of a NAT box and the choice
is easy.
That's true if you don't put the indirect operational and user
costs of NAT, plus the opportunity cost of innovation blocked
by NAT, into the equation. It *is* hard to get this into the budget
unless you think strategically, and factor in the way IPv6 is
designed to handle multiple PA prefixes simultaneously.
If your choices are PI vs PA then yeah NAT does look very attractive,
but if you can have PA and "private"-PI (aka ULA) then things look a
lot less blurred (IMHO).
IMHO, you underestimate how much IT folks hate renumbering.
They hate renumbering IPv4 networks. I do too, having managed such an
operation a couple of times. It's as a result of that hatred that
IPv6 came out as it is, making RFC 4192 possible.
This is *not* to say that anyone will renumber weekly, and big networks
will avoid it (and are therefore candidates for PI). But for smaller
networks, the hatred should be substantially less, and balance the hatred
of NAT.
Brian
--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6@ietf.org
Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------
