+1
Although I’d rather see multiple high site admins taking this on. It’s a bit much for one person.
How do admins handle inactive links at the moment? Over here we monitor our links, and push a use it or loose it policy. If there are wuggers who switch their links off for long enough and ignore our notices, we revoke their IP addresses and return them to our pools. When you’re not charging money for a service you have to implement a use it or loose it strategy, it’s that simple. All admins should be doing this in their districts/areas.
Ping scans aren’t very useful for the reason pmurgs pointed out, because of the inefficient nature of subnetting, and because of the way IP addresses are assigned and used. There’s no way anyone can realistically expect most or even half of all usable address space to be actively in use - networks simply don’t work like that. For example, I have a /28, but right now as I type, less than half of it is live. At the same time there’s no way my network would be usable with a smaller allocation, because the next size down is less than half the size, and because the number of devices on my network is dynamic, not static. If you think in terms of individual IP addresses you have the wrong perspective of IP networks. Think in terms of IP subnets, and make sure there are no prefixes routed to networks that are inactive.
As Beetle pointed out, we have no shortage of IP addresses. Reducing the size of allocations to wuggers would be a painful waste of time. If anything allocations should be larger. Who has less than 5 devices on their networks these days? What are we, Amish? Personally I have 5 devices all to myself on my network, that excludes the shared devices like switches, routers, servers, TVs, etc. I rarely give less than a /28 to wuggers, and I always reserve the adjacent /28 if it’s available in the pool. High sites get no less than a /24, and also get reserved the adjacent /24 if it’s available in our pool.
So no shortage of IP addresses, but what feels like a mess of random, unplanned allocations. Why are there prefixes smaller than /25 on the IP Address wiki page?? Even some /29s there, geez! Time to start putting the district model to better use. Search the wiki for “deepsouth” and see how we’re doing things… (we’re still busy pulling up our broeks)
So don’t worry about running out of addresses. Do worry about how you plan and make your allocations, and do worry about monitoring your networks for dead links. Once we can get that right we’ll hopefully be ready for the next big step - IPv6. 