Addressing plan exercise for our IPv6 course

Fri Jul 23 05:23:17 UTC 2010

On Jul 22, 2010, at 9:51 PM, Joe Maimon wrote:

> 
> 
> Mark Smith wrote:
>> On Fri, 23 Jul 2010 00:33:45 +0100
>> Matthew Walster<matthew at walster.org>  wrote:
>> 
>>> On 22 July 2010 14:11, Alex Band<alexb at ripe.net>  wrote:
>>>> There are more options, but these two are the most convenient weighing all
>>>> the up and downsides. Does anyone disagree?
>>> 
>>> I never saw the point of assigning a /48 to a DSL customer. Surely the
>>> better idea would be to assign your bog standard residential DSL
>>> customer a /64 and assign them a /56 or /48 if they request it, routed
>>> to an IP of their choosing.
>>> 
>> 
>> I estimate that an addressing request will cost the ISP at least 15
>> minutes of time to process. When a minimum allocation of a /32 contains
>> 16 777 216 /56s, do you really need to create that artificial
>> addressing cost, eventually passed onto the customer?
> 
> Funny how so much concern is given to eliminating the possibility of end users returning for more space, yet for ISP's we have no real concern with what will happen when they near depletion of their /32 what with /48s to some thousands customers, aggregation, churn, what have you.
> 
There's no need to give it a lot of concern because that process is pretty well understood and not particularly different from the current process in IPv4.

When an ISP runs out, they apply for more from either their upstream, or, their RIR. Just that simple.

> The effort and cost of that on the organization is hard to predict, especially as how it may vary from size to size, organization to organization. Furthermore, everyone else pays with a DFZ slot.
> 
Yeah, but, the number of DFZ slots consumed by this in IPv6 will be so much smaller than IPv4 that I really find it hard to take this argument seriously.

Additionally, it's not necessarily true due to allocation by bisection.

> /48 per customer gives the customer as many potential subnets as you have potential customers.
> 
You say that like it is a bad thing.

>> 
>> With more address space than we need, the value we get is addressing
>> convenience (just like we've had in Ethernet addressing since 1982).
>> There is no need to make IPv6 addressing artificially precious and as
>> costly as IPv4 addressing is.
> 
> A balance should be struck and for that to happen, weight must be given to both sides.
> 
And it has. /32 is merely the default minimum allocation to an ISP. Larger blocks
can be given, and, now that the RIRs are allocating by bisection, it should even
be possible in most cases for that additional space to be an expansion of the
existing allocation without changing the number of prefixes.

e.g. 2001:db8::/32 could be expanded to 2001:db8::/28

16 times as much address space, same number of DFZ slots.

Owen