Re: Small IX IP Blocks

[Laszlo Hanyecz <laszlo () heliacal net>]

Mike,

I think it's fine to cut it up smaller than /24, and might actually help in keeping people from routing the IX prefix 
globally.

-Laszlo


On Apr 5, 2015, at 12:35 AM, Mike Hammett <nanog () ics-il net> wrote:

> Okay, so I decided to look at what current IXes are doing. 
>
> It looks like AMS-IX, Equinix and Coresite as well as some of the smaller IXes are all using /64s for their IX 
> fabrics. Seems to be a slam dunk then as how to handle the IPv6. We've got a /48, so a /64 per IX. For all of those 
> advocating otherwise, do you have much experience with IXes? Multiple people talked about routing. There is no 
> routing within an IX. I may grow, but an IX in a tier-2 American city will never scale larger than AMS-IX. If it's 
> good enough for them, it's good enough for me. 
>
> Back to v4, I went through a few pages of PeeringDB and most everyone used a /24 or larger. INEX appears to use a /25 
> for each of their segments. IX Australia uses mainly /24s, but two locations split a /24 into /25s. A couple of the 
> smaller single location US IXes used /25s and /26s. It seems there's precedent for people using smaller than /24s, 
> but it's not overly common. Cash and address space preservation. What does the community think about IXes on smaller 
> than /24s? 
>
>
>
>
>
>
> ----- 
> Mike Hammett 
> Intelligent Computing Solutions 
> http://www.ics-il.com 
>
>
>
> ----- Original Message -----
>
> From: "Brendan Halley" <brendan () halley net au> 
> To: "Mike Hammett" <nanog () ics-il net> 
> Cc: nanog () nanog org 
> Sent: Saturday, April 4, 2015 6:10:34 PM 
> Subject: Re: Small IX IP Blocks 
>
>
> IPv4 and IPv6 subnets are different. While a single IPv4 is taken to be a single device, an IPv6 /64 is designed to 
> be treated as an end user subnet. 
> https://tools.ietf.org/html/rfc3177 section 3. 
> On 05/04/2015 9:05 am, "Mike Hammett" < nanog () ics-il net > wrote: 
>
>
> That makes sense. I do recall now reading about having that 8 bit separation between tiers of networks. However, in 
> an IX everyone is supposed to be able to talk to everyone else. Traditionally (AFAIK), it's all been on the same 
> subnet. At least the ones I've been involved with have been single subnets, but that's v4 too. 
>
>
>
>
> ----- 
> Mike Hammett 
> Intelligent Computing Solutions 
> http://www.ics-il.com 
>
>
>
> ----- Original Message ----- 
>
> From: "Valdis Kletnieks" < Valdis.Kletnieks () vt edu > 
> To: "Mike Hammett" < nanog () ics-il net > 
> Cc: "NANOG" < nanog () nanog org > 
> Sent: Saturday, April 4, 2015 5:49:37 PM 
> Subject: Re: Small IX IP Blocks 
>
> On Sat, 04 Apr 2015 16:06:02 -0500, Mike Hammett said: 
>
> > I am starting up a small IX. The thought process was a /24 for every IX 
> > location (there will be multiple of them geographically disparate), even though 
> > we nqever expected anywhere near that many on a given fabric. Then okay, how do 
> < we d o v6? We got a /48, so the thought was a /64 for each. 
>
> You probably want a /56 for each so you can hand a /64 to each customner. 
>
> That way, customer isolation becomes easy because it's a routing problem. 
> If customers share a subnet, it gets a little harder....