This keeps the number of routes in the interdomain routing system at an acceptable level. The number of aggregated routes is much lower than the number that would be needed if each end-site's individual routes would need to be propagated throughout the whole interdomain routing system.
"Acceptable level" Hints at a technological weakness in current router hardware. May also be related to route propgation latencies.
The reason for this arrangement is the load on the interdomain routing system. If the customer used the address space assigned to and aggregatable by their previous service provider when connecting to another service provider, their routing information could not be aggregated and would have to be propagated sepa- rately throughout the whole interdomain routing sys- tem.
Again, hints at a technological weakness in current router hardware. May also be related to route propgation latencies. At no point does this address the scaling problems that IPv6 (or followons) will bring. (There are some who will retire before we need a replacment for IPv4, but I'm not one of them)
At the time of this writing there is growing concern among the operators of major transit routing domains in the Internet that the number of individual routes and their associated information is growing faster than the deployed routing technology will be able to handle. Parts of the interdomain routing system are already operating at capacity.
It has been argued that PI addresses will quickly become be totally useless since the Internet routing system will not be able to support them any longer.
A very clear indication that there is a problem in router technology.
Consequently it has been suggested that the regional IRs should immediately stop allocating and assigning PI space and only allocate PA space to service providers.
So there is the suggestion that policies be created/enforced to accomodate problem routing technology? Is this really what we want to do? --bill