IPv6 Addressing Help

Chris Gotstein chris at uplogon.com
Fri Aug 14 10:31:52 CDT 2009

I think we had to let ARIN know the time frame of deploying IPv6 and how 
many customers we expected to put on in the first couple years.  They 
did not ask for an addressing scheme.

Reading over the RFC's and other IPv6 resources, we have decided to hand 
out /56's to small/home/SOHO customers and /48's to larger customers.

I'm just not able to wrap my brain around the subnetting that needs to 
be done on the router.  Like i said before, i think i'm just over 
complicating it in my mind.

Chris Gotstein
Sr Network Engineer
UP Logon/Computer Connection UP
500 N Stephenson Ave
Iron Mountain, MI 49801
Phone: 906-774-4847
Fax: 906-774-0335
chris at uplogon.com

Thomas Mangin wrote:
> I do not know about arin but ripe changed it's policy so you only have 
> to say "pretty please" to receive your allocation. It better that way 
> anyway.
> Thomas Mangin
> On 14 Aug 2009, at 16:17, Jeroen Massar <jeroen at unfix.org> wrote:
>> Chris Gotstein wrote:
>>> We are a small ISP that is in the process of setting up IPv6 on our
>>> network.  We already have the ARIN allocation and i have a couple
>>> routers and servers running dual stack.  Wondering if someone out there
>>> would be willing to give me a few pointers on setting up my addressing
>>> scheme?
>> Strange, I recall that you had to submit one when requesting address
>> space from ARIN. Why don't you use that one?
>>> I've been mulling over how to do it, and i think i'm making it
>>> more complicated than it needs to be.  You can hit me offlist if you
>>> wish to help.  Thanks.
>> It all depends on your network and how you want to set it up, but for
>> the sake of internal aggregation:
>> * Determine the expected amount of IPv6 customers at a certain
>>   location for the next X years, making X > 2 (though 10 is probably a
>>   better idea, just in case, if don't want to do it again ;) )
>> * Take that number round it up to a power of 2
>> * Every customer gets a /48, you know the number, which is a power of
>>   2, thus root it, and you know how many bits you need at that site
>>   eg expect 200 customers, round to power of 2 thus 256, which is 2^8,
>>   thus you will need a /48 + 8 bits = /40 at that location.
>> You now know how much address space you need at that location for the
>> next X years.
>> Repeat that for all your locations / routing areas, basically the PoPs
>> or termination points of your customers; or if you are really big do
>> that per city/town/suburb. Keep enough space (the rounding helps there
>> quite a bit, especially with numbers like 50k customers ;)
>> Now you have an overview of what you expect to be allocating at each and
>> every site. To add a little growth/future proof and to make live easy,
>> you could either opt at this stage to round everything off to 'nice'
>> numbers, eg only use /40's or /36's per PoP. Thus making everything the
>> same, or doing things like grouping smaller PoPs together.
>> Then when you have done that, take those blocks, and try to squeeze them
>> a bit together. You should now have arrived to the address plan that you
>> originally submitted to ARIN.
>> Fill those blocks into a nice database, roll a PHP/shell/perl/whatever
>> script to spit out your router configuration and presto: you are done.
>> Enjoy the weekend ;)
>> Greets,
>> Jeroen

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