On Fri, Aug 14, 2009 at 11:03 AM, Chris Gotstein<chris@uplogon.com> 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? 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.
Hi Chris, Suggested scheme: Router loopback: /128 Router serial link: /126 Router/server ethernet link: /64 Dynamic IP customer: /128 from a /64 pool Dynamic IP always-on customer: Not sure there are any well conceived and solidly implemented answers here. Your customer's "DSL router" isn't going to work and you shouldn't expect a production-grade IPv6 NAT CPE any time soon. You can go DHCP or autoconfiguration and let him chew as many /128's as he wants but then you'll run into the broadcast traffic problem same as when you used DHCP for IPv4. On the flip side, you can convert your always-on folks to static IP customers with the risk of a routing explosion as these customers move around and as you merge and split service POPs. I'm not aware of any way of dynamically assigning an IPv6 subnet to a customer that's as well automated as IPv4 /32 dynamic assignment to a DSL router with an RFC1918 NATed interior, but that may just be my ignorance since I haven't needed to research it. Static IP customer: /60 Any static-IP customer who bothers to ask: /48 In all other respects follow whatever strategy works for you for IPv4 wrt routing areas and aggregation. Several notes: The RDNS delegation boundary for IPv6 is 4 bits (as opposed to IPv4's 8 bits). This makes boundaries like /48, /52, /56, /60 and /64 very convenient. You should probably avoid customer assignments that don't fall on one of those boundaries. Ethernet in IPv6 is intended to work on a /64 subnet. You can make it work on any other size but why create extra hassle for yourself for no good reason? I recommend /60 as the customer default where most folks suggest /56 or /48. The IPv6 use profile looks a heck of a lot like the IPv4 use profile and /60 is 16 subnets. How many of your customers find a reason to use more than 3 IPv4 subnets, including their RFC1918 ones? Relatively few. Giving every customer enough subnets by default to meet 90% of the typical usage profiles is not the worst idea in the world... IMHO it's a pretty bright idea. But there's no need to be damnfool wasteful about it. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004