[arin-discuss] Trying to Understand IPV6

[Owen DeLong]

On Sep 13, 2010, at 12:01 PM, Tim Howe wrote:

> On Mon, 13 Sep 2010 19:32:33 +0100
> <michael.dillon at bt.com> wrote:
> 
>>> If I assigned a customer say an IPV4 /21 in IPV6 this would translate
>>> into a /56? If I'm not mistaken a /56 would translate into something
>>> like 65,000 host addresses? That just seems like a lot of hosts to me,
>> 
>> Anyone in this position should simply assign a /48 to every customer site
>> no matter how big or small. A one bedroom apartment gets a /48. A manufacturing
>> plant with 5 buildings including a 4-story office block, gets a /48. 
>> No exceptions.
> 
> 	This is slightly different than I have been led to think...  It
> seems wise, when you know the customer has no intention of having
> multiple networks, to provide a /64.  Not because you fear wasting
> address space.  Currently, most folks will have a single IP (half of the
> connecting range to their provider) and their LAN in RFC1918 space using
> that address for NAT.  The IPv6 equiv to that would be a /64 connecting
> range and another /64 range to use for their LAN.  This has been my plan
> as most of these customers don't know (and don't wish to know) how to
> subnet v4, so I am sure handing them a /48 and expecting them to use it
> correctly is out of the question and unnecessary.  This seems to be what
> HE is doing for tunnel accounts.
> 
That is what HE is doing for tunnel accounts. However, if I were designing
the tunnel service today, I would do it differently.

If I were designing it, I would assign every customer a /48 and those customers
that did not yet need the /48 would simply use the first /64 from that /48.

> 	Anyone wanting/needing multiple networks (or who even thinks they
> might, and knows what a /48 is) can and should have a /48, no problem.
> 
> 	I am just a small provider with mostly small business accounts
> and colo, so maybe my situation isn't typical...
> 
More so than you may think.

> /64 per network
> /48 per customer with more than one network (so they can have /64 per network)
> 
> 	Is this flawed or no longer the prevailing way of thinking?
> 
Not entirely, but, as I said, if I were building a network from scratch today,
I would assign every customer a /64 for link and a /48 for each end site.
If they don't need more than one network at an end site, then just have
them use the first /64 from that /48 and everything still works just fine.
That way, expansion does not require renumbering and when they figure
out that they need the /48 you have already given it to them.

Improved customer service through the illusion of ESP. (A term I believe
was originally coined by E. Zwicky for systems administration)

Owen