Implementation Models for IP Telephony Interconnection at Large
Mohamed Boucadair, Isabel Borges, Pedro Miguel Neves, Olafur Pall Einarsson · 2011
In order to allow remote users to reach telephony destinations that are not attached to the local ITAD (IP Telephony Administrative Domains), Service Providers should exchange information that is required for a call request to be appropriately forwarded. IP telephony reachability information is stored by a dedicated node called a Location Server (LS). Additional functions are required, which have been mentioned in previous chapters.