[arin-discuss] Trying to Understand IPV6

[Aaron Hughes]

Darryl,

I have yet to see a good website on this and am actively working with a few folks to write a BCP on the subject.

The short general operational practice is (and there is a lot of debate on this subject).. Customers who get 1 subnet (like a collocation customer with a server) get assigned a /64. Customers with more than 1 subnet get a /48.

There are many people who would argue this is wasting IP space (I believe this will start a thread here) and /56s are a nice middle option.

The point of this is to think in terms of number of subnets rather than number of hosts.

1 subnet = 1 /64

256 subnets = 1 /56

65,536 subnets = /48

I made a quick and dirty table here: http://bind.com/?path=netmasks6 that may help.

As we make progress on the IPv6 subnetting BCP, I'll certainly share with this list.

Cheers,
Aaron

On Mon, Sep 13, 2010 at 01:24:19PM -0400, Schnell, Darryl wrote:
> Can anyone recommend a good IPV6 website for Beginners? I've read about eight web sites which say the same things and I feel like my head is going to explode. I guess the problem I'm having is trying to understand how an IPv4 CIDR notation translates in an IPv6 CIDR in order to fill out ARIN IPV6 Allocation Template future usage section. My actual question is -
> 
> 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, especially when most of the time I'm working with networks that are /26 or smaller. I guess my big problem is confusion over labeling. What would be the equivalent of a /26, /27, /28 or have we done away with blocks that small and simply would just assign a /56 instead?
> 
> Does any of the gibberish I wrote make any sense at all?
> 
> Any help anyone can offer is much appreciated.
> 
> D -
> 

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Aaron Hughes 
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