cal, mechanical function. However, in the past few years the different interests around IP address allocation have politicized the process, and even the setup has been questioned. However, in our view, this picture makes sense when looking at the Internet from a technical perspective. The highest level of the hierarchy is the IETF. The IETF is the standardization orga- nization, which is responsible for specifying the IP technology - including the Internet Protocol itself. The IETF specifications specify how long is the address, what is the addressing architecture, and what are the special address ranges that are not allocated as unicast addresses. The global allocation of IP unicast addresses is the responsibility of the IANA [33], which is operated by ICANN [34]. In IPv4, IANA allocated /8 address blocks for Specifications AfriNIC APNIC LACNIC RIPE NCC Figure 1.5 IP address allocation hierarchy. Introduction the Regional Internet Registries (RIRs) [35]. The RIRs are responsible for allocating addresses regionally. Today five RIRs exist: African Network Information Center (AfriNIC) in Africa, Asia-Pacific Network Information Center (APNIC) in Asia Pacific, American Registry for Internet Numbers (ARIN), Latin America and Caribbean Network Information Center (LACNIC) in Latin America, and Réseaux IP Européens Network Coordination Centre (RIPE-NCC) in Europe. The RIRs are responsible of allocating IP addresses to the Local Internet Registries (LIRs) in their region. The LIRs are generally operators, or larger organizations that allocate the IP addresses to the final users of the addresses - the hosts and routers that use the addresses. The allocation of IP addresses to the RIRs from IANA, and to the LIRs from the RIRs, are based on the global or RIR policies. The LIRs usually allocate addresses to the end users based on commercial or technical grounds. Basically, how many IP addresses are allocated to different computers behind a consumer broadband line is based on the contract that the end user has made with the o