 with information flow (A3). Corresponds to FFS whether the terminal name, or proxy name, or both is included within this and subsequent register messages. A3 Cx-Query h-Interrogating CSCF to h-HSS Information control: proxy name, subscriber identity, local network contact name, and local network capabilities. Initiation of information flow: receipt of information flow (A2). Processing upon receipt: information flows (A3) (A4) and (A5) are treated to- gether. A4 between h-Interrogating CSCF and h-HSS Information control: subscriber identity, local network capabilities, other informa- tion. Initiation of information flow: receipt of information flow (A2) and (A3). Processing upon receipt: The h-HSS and the h-interrogating CSCF determine whether the serving CSCF corresponds to the home network or the local network (when the local network is not the home network). When the serving CSCF is in the home network, the name of the serving CSCF gets determined, otherwise it is agreed that the register information flow should be forwarded to the local network to select the serving CSCF. Towards IP Based Networks A5 Cx-Query-Response h-HSS to h-Interrogating CSCF Information control: required capabilities, other FFS. Initiation of information flow: receipt of information flow (A3) and procedure (A4). Processing upon receipt: we assume that after processing information flow (A5) the authentication of the user has been completed and is successful³. The h- interrogating CSCF and the hHSS have determined the serving CSCF, or that the serving CSCF is located in the local network. The behaviour of the h-interrogating CSCF depends on whether the serving CSCF belongs to the home network or in the visiting network. When the serving CSCF corresponds to the home network, we follow information flow B; otherwise we follow information flow C. Figure 9.14 il- lustrates this sequence. The h-interrogating CSCF has received the name of the HSS and will forward this to serving CSCF for the purpose of downloading the subscriber profile. A6 h I-