[arin-ppml] 2010-8: Rework of IPv6 assignment criteria

[michael.dillon at bt.com]

> What is the definition of site?  Any building/campus in the network?

A site is a place that one would normally distinguish from another place. For an ISP, a whole college campus might be considered a site since they serve it with a pair of redundant fiber links, but for the college IT folks, each building might be considered a site, and in some cases, part of a building. For instance if two departments share a building, and there are two separate network links to that building, then it is reasonable to consider it as two sites.

In the above scenario, the ISP would probably say to the college folks, "you are one site, here is your /48 assignment". The college folks would then say, "we already have our IPv6 architecture in place, and in fact we have 37 sites therefore we would like 37 /48 allocations". In this scenario, the right thing to do is to give the college the number of /48s that they need to cover the site architecture that they have deployed. That is because "SITE" can only be defined locally where there is enough info to see how to distinguish one place from another.

A residential apartment building with 76 apartments would have just over 76 sites, since you need to allow for at least one if not more /48s to cover the building maintenance department. Each individual residence is a site.

> For example, is every large (1501 stores or more) retail company in the
> ARIN region entitled to a /32?

Clearly they have more than 1501 sites because they also have warehouses and a head office site. The question is, do they have a network? Two identical retail chains could answer that question differently. One might say that they buy Internet access from two different ISPs and their IT department maintains an IPSEC VPN connecting all the sites, therefore they just get /48s per site like any other ISP customer. But another retail chain might buy IP-MPLS connectivity from a large network operator and run their own IP network over this infrastructure using an ARIN PI block, and then peer with their network operator's ISP division over the big pipe into head office.

A site can only be defined locally, and the most important thing is that there is some distinction between the location of one site and another. This distinction is what makes it into a "site". And the same physical collection of sites could receive addresses in more than one way. Either PI from ARIN or PA assignments from an ISP as above. Or they could even light up dark fiber and get an ARIN PA allocation as a network operator.

It might be a bit of a stretch to see a retail chain as a network operator, although I am aware of at least one German/Polish chain that has a RIPE PA allocation like that. But it is less of a stretch to see a cinema chain operating their own network over dark fiber, and cinema is a retail sort of business.

>  They'd all meet requirement 6.5.8.1(c)
> below; most or all would meet 6.5.8.1(a), so that gets them in the door
> for an IPv6 assignmnet of some size. 

It's not a question of what requirements do they meet, it is a question of what are they doing. Are they operating a network? Is it a stable fixed size network (PI)? or a constantly growing network (PA)? Or do they just buy services from ISPs?

> This isn't necessarily a problem -- IPv6 space isn't scarce the way
> IPv4 is -- I'm just asking what you intended the definition of "site"
> to be.

That's exactly right. IPv6 space is not scarce, and if there is a clash between the fundamentals that I have descrivbed above, and ARIN policy, then it is highly likely that ARIN policy will adjust. There is a lot of change going on right now with networks and how people make use of them, and that will drive a shift in demand patterns for IPv6 once we get past the chaotic transition period. It's best to not shoehorn people's network designs into ARIN policy quirks, but instead keep the network architectures clean and simple and demand ARIN policy changes to fit that.

--Michael Dillon