 Globe Project [29], the Handle System allows, but does not require, hierarchy in the resolution mechanism and administration. This allows for delegation to enable local resolution and disconnected usage. The handle itself, although not semantic by design, may be used to convey other naming mechanisms such as DNS addresses through mapping and/or direct inclusion. This is not possible with a system that is dependent on hashes for the identifiers themselves. Another level of indirection (for mapping unfriendly names to friendly names) on top of a flat resolution infrastructure introduces unnecessary overhead. The separation between the semantic-free referencing infrastructure and the human-friendly names advertised in SFR [27] and [26] can be done within the same system. This is the approach that the Handle Sys- tem takes. A particular meaningful handle can refer to another non-meaningful handle within the same system. Hence, multiple competing third parties can manage the meaningful handle space. The basic distribution of the handle namespace [12] into prefixes allows for distributed secure delegation through the consolidation of structured prefixes C 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security and the segmentation of the namespace to accommodate commercial vendors offering dedicated resolution infrastructure. With support from the National Science Foundation (NSF), the Corporation for National Research Initia- tives (CNRI) demonstrated the mapping of DNS names to handles and vice- versa. We also demonstrated this approach in enabling SIP call completion, regular Web service resolution, and e-mail services. The existence of mul- tiple prefixes plus the currently deployed architecture of Handle-DNS and DNS-Handle proxies enables us to provide a gradual migration environment from the current Internet in order to support existing applications and to enable new ones. Another difference is that the current Handle System ser- vice model involves a global registry, and may invol