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Re: IPv6 Addressing Help


From: Chris Gotstein <chris () uplogon com>
Date: Fri, 14 Aug 2009 10:31:52 -0500

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 () 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 () 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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