Teliasonera Cisco IEEE 802.21 standard defines three distinct service types to facilitate link layer handovers across heterogeneous technologies. This document focuses on the Diameter Network Access Server (NAS) to home Authentication, Authorization and Accounting server (HAAA) interface defining a number of Diameters AVPs containing domain names or IP addresses. Such information is related to IEEE 802.21 services assisting a mobile node in handover preparation (network discovery) and handover decision (network selection).