Mechanisms are provided for assigning addresses for use in communications between computing devices. With these mechanisms, a centralized domain name registrar server assigns a unique global identifier to a domain of a site such that the unique global identifier uniquely identifies the domain. The unique global identifier is received in a data processing system from the centralized domain name registrar server. The site is divided into a plurality of sub-domains and a unique sub-domain identifier is assigned to each sub-domain in the site such that the unique sub-domain identifier uniquely identifies a corresponding sub-domain in the site. The global identifier for the domain of the site and the sub-domain identifiers of the sub-domains in the plurality of sub-domains are provided by the data processing system to routers of the site for use in associating addresses with devices of the site.