You can also hand out ranges. Instead of asking the system for one ID, you ask it for 1000 contiguous IDs, and you ask for another range when you run out. This

You can also hand out ranges. Instead of asking the system for one ID, you ask it for 1000 contiguous IDs, and you ask for another range when you run out. This will reduce the load on the ID-creating-system by 1000x (or your choice of number) and has the advantage that systems don't need to know how many peers they have. (beware of the herd though, if you don't persist it every system will come asking at startup)