[arin-ppml] IPv6 Allocation Planning

Charles O'Hern charles at office.tcsn.net
Thu Aug 12 16:01:44 EDT 2010

michael.dillon at bt.com wrote:
>> I was simplifying a bit.  About a third of our customers are dynamic
>> 802.11 hotspot customers.  Since those are each single hosts,
> You've got to be joking.
I wasn't at the time, but have since become aware of how narrow my view
and thought process have been.
We are learning.

> Have you never heard of tethering? This is
> where one device with a wireless connection, allows a second device
> to transport traffic over that connection. I did it back in 2000
> with a Nokia mobile phone tethered to a Palm V over infrared to run
> a web browser and check my email at yahoo.com. Nowadays it is more
> often a 3G cellphone tethered via wifi to a netbook or iPad, but
> there are many variations, some of which involve so-called mifi
> where a wifi device acts as a router for a bunch of other
> devices.
> That means that many of your customers have 2 hosts and some
> of them have entire subnets connected. On IPv6 you should not
> give a wifi customer less than a /64, and it may even make sense
> to assign a /56 given the march of miniaturization and device
> proliferation.
>> I can't
>> foresee allocating  more than a /64 per hotspot 
> Even if you assign /64s to the customers on the hotspot, it still
> makes sense to allocate a /48 to the hotspot.
> Here is a rule of thumb. Write up your IPv6 addressing plan.
> Now look at each level of the aggregation hierarchy and ask
> yourself, "am I being wasteful?". If the answer is no, then
> you got it wrong and should increase the allocation size at 
> that layer and probably all layers above it.
I sat down this morning and tried this.  Its quite difficult to overcome
the ingrained habits that were natural to IPv4.  It will be more
difficult to convince the bosses to change their thinking.  But we will
be trying to do so.
> If you don't do that you are just shooting yourself in the foot
> and will need to redo your network architecture in 3 years
> while your competitors are laughing at you because they understood
> the fundamental ACCORDION principle of IPv6 addressing. You have to
> be able to expand each level in the hierarchy without affecting
> higher or lower levels in the hierarchy.
> For instance, a customer signs up for Internet access for their
> laptop at home. You assign them a /48. You never hear from
> them again except to buy bigger bandwidth every do often
we'll hear from them... guaranteed.  But I see your point... they'll
never have to request more addresses and/or renumber.  (Unless we're on
PA, of course)
> and one day you are driving by and see that this
> customer now has a medical clinic with 10 people working
> there and a special radiology clinic with a scanner that
> sends multi gigabyte scans to the local hospital several
> times a day. You walk in and there are network connected
> devices everywhere. The TV in the waiting room is showing 
> Hulu programs, the phones are all Cisco VoIP devices,
> the medical personnel are all carrying iPadv7 tablets
> and there are three closets full of cables and server racks
> which the chief doctor uses to serve up his lectures 
> via the Open University on the Internet. And that /48
> allocation still has space to spare.
Yes I can see this happening. 
> That is what IPv6 addressing is meant to bring us.
> --Michael Dillon
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Charles O'Hern
Network Operations
TCSN - The Computer Shop Netlink
1306 Pine St. Paso Robles CA 93446
1-(805) 227-7000  1-(800) 974-DISK
http://www.tcsn.net  abuse at tcsn.net

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