Provider Independent Address Space

Provider Independent Address Space ( PI address space) are blocks of Internet Protocol addresses (RIR ) can be assigned directly to an end user of a Regional Internet Registry without being still dependent on an Internet service provider for address assignment.

This gives the owner the ability to change the service provider without having to change the assigned IP addresses, or even to be able to use multiple service providers simultaneously in a multi-homed configuration. On the other hand, this increases the granularity of the address spaces as affiliate networks are grouped not by an ISP in large address spaces (PA address space). This causes problems when routing the individual address ranges, as in Classless Inter- Domain Routing (CIDR) described, there can be no assurance that a small PI address space is routed in all parts of the Internet.