BBC does IPv6 ;) (Was: large multi-site enterprises and PI

Sat Nov 27 16:43:10 UTC 2004

fred at cisco.com (Fred Baker) writes:

> My reasoning: well, I work for an outfit that has an AS number, meaning
> that it has a certain number of ISPs. It is also an edge network.  It
> has ~35K employees and VPNs a subnet to each employee's home. ...
> 
> Hence, I will argue that more than 65K subnet prefixes should be
> allowable to such an edge network. ...

those of us who prefer static assignment + dhcp6 over EUI64 find a /64 to
be an obscene waste of address space on a per-lan (or per-vlan) basis, but
sadly there are already some cool wireless gadgets whose idea of ipv6 does
not include either static or dhcp6 addressing, so there's some tension.

my house has four vlans (core, family, guest colo, and wireless) -- so in
the cisco home networking model i'd need a /62 for fewer than 50 hosts?

i mention this not just because it's a weekend but because fred also said:

> The thing that brings me out here is the "one size fits all" reasoning
> that seems to soll around this community so regularly. "Multihoming
> should always use provider-independent addressing" and "Multihoming
> should always use provider-dependent addressing" are the statements in
> this debate.  ...

and the unifying principle here is that people who do resource planning
for both themselves and others, will tend to make certain assumptions
about what the "others" actually need.  could be they'll make the mistake
of assuming that a multinational's needs are the same as an isp's (or
that they aren't and can't be similar), as fred points out.  or it could
be that they'll legislate /64's per-lan or per-household.  "same error."

in arin-land we've seen the minimum allocation shift around over the years
in a sort of "hunt and peck" attempt to discover the equilibrium between
"too small for global routeability" and "too large for people who need it
to be able to qualify for".  in ipv6 there's been a pre-emptive strike 
against this kind of thing -- the minimum size is so large that almost
nobody who needs it will ever qualify for it.  coming as it did after all
architectural design-level attempts to enable rapid renumbering were
killed in their bassinets, it's enough to make one wonder either "why did
we expect ipv6 deployment under these conditions?" or "who wants it dead?"

i life fred's reasoning.  companies with size and qualifications like
cisco's should qualify for an ASN and for PI space.  all the world's not
a home-DSL or home-cable or isp-colo network.  routing shouldn't always
follow addressing.  we'll need to discover a workable equilibrium unless
we want to encourage NAT in IPv6 the same way we (passively) encouraged it
in IPv4.
-- 
Paul Vixie