ISP customer assignments

TJ trejrco at gmail.com
Tue Oct 6 13:45:45 UTC 2009


Actually, I would argue IPv6 is a bit of both classfull and classless.
(Moreso the latter ...)

The protocol itself, /64 "mandate" aside, certainly allows you to place
arbitrary-bit-long prefix lengths - and to aggregate/summarize at any
point.  And /64s do not so much apply in some cases, whether 'permitted' by
spec (/128) or not(/126).  Thus classless.

OTOH, we have policies that define how we will allocate this address space
that do look eerily similar to the Classfull methods we started off with in
IPv4.

I too am always ... hmm, surprised isn't the right word ... when this
angers|scares|confuses people.


Anyway, I enjoy the conversation and hope this helps ...
/TJ


On Tue, Oct 6, 2009 at 9:36 AM, Dan White <dwhite at olp.net> wrote:

> On 05/10/09 22:28 -0400, Ricky Beam wrote:
>
>> On Mon, 05 Oct 2009 17:13:37 -0400, Dan White <dwhite at olp.net> wrote:
>>
>>> I don't understand. You're saying you have overlapping class boundaries
>>> in your network?
>>>
>>
>> No.  What I'm saying is IPv6 is supposed to be the new, ground-breaking,
>>  unimaginably huge *classless* network.  Yet, 2 hours into day one, a
>>  classful boundary has already been woven into it's DNA.  Saying it's
>>
>
> I would disagree. IPv6 is designed around class boundaries which, in my
> understanding, are:
>
> A layer two network gets assigned a /64
> A customer gets assigned a /48
> An ISP gets assigned a /32 (unless they need more)
>
>  classless because routing logic doesn't care is pure bull.  In order for
>>  the most basic, fundamental, part (the magic -- holy grail -- address
>>  autoconfig) to function, the network has to be a minimum of /64.  Even
>>  when the reason for that limit -- using one's MAC to form a (supposedly)
>>  unique address without having to consult with anything or fire off a
>>  single packet -- has long bit the dust; privacy extensions generate
>>  addresses at random and have to take steps to avoid address collisions, so
>> continuing to cling to "it has to be 64bits" is infuriating.
>>
>
> IPv6 provides you the opportunity to design your network around your layer
> two needs, not limited by restrictive layer 3 subnetting needs.
>
> If your complaint is that all devices in a /64 are going to see IPv6
> broadcast/multicast packets from the rest of the devices in that subnet,
> then don't assign 2^64 devices to that subnet.
>
> I still don't understand why its infuriating to you, but I can certainly
> tell that it is.
>
> --
> Dan White
> BTC Broadband
>
>


-- 
/TJ



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