9. AS Space exhaustion

The AS number space is a finite amount of address space. It is currently defined as a 16 bit integer and hence limited to 65535 unique AS numbers. At the time of writing some 5,100 ASes have been allocated and a little under 600 ASes are actively routed in the global Internet. It is clear that this growth needs to be continually monitored. However, if the criteria applied above are adhered to, then there is no immediate danger of AS space exhaustion. It is expected that IDRP will be deployed before this becomes an issue. IDRP does not have a fixed limit on the size of an RDI.