Step 2: An IP user may also use xDSL interface as the transport medium to an NGN. Protocol for • xDSL interface may be Ethernet which enables broadband data flows and services, e.g., VoD, IPTV, VoIP and Internet. Step 3: In this step, the legacy end systems are replaced by NGN end systems and twisted copper • lines are replaced by optical fibre, either fibre-to-the-curb (FTTC) or fibre-to-the-home (FTTH) to increase transmission speed. Figure 2-1: Migration of xDSL access to NGN 3 Signaling and control scenarios A possible scenario for migration of signalling in the core network consists of following three steps. Step 1: In this step, signalling functions are transferred from the TEs to the independent units • creating an STP mesh network (partial or complete). Step 2: In this step, STPs are upgraded to the SGs and are placed on the edge between PSTN/ISDN • and NGN. In this case, both the legacy network and NGN co-exist with each other. Step 3: In this step, all LEs and TEs are replaced by NGN. • Figure 3-1: Realization of signalling migration scenario 4 Services migration scenarios Scenario 1: In this scenario, existing IN services are reused in NGN by implementing SSF in the CS. • Both PSTN/ISDN and NGN Figure 4-1: Realization of scenario 1
• Step 2: An IP user may also use xDSL interface as the transport medium to an NGN. Protocol for xDSL interface may be Ethernet which enables broadband data flows and services, e.g., VoD, IPTV, VoIP and Internet. • Step 3: In this step, the legacy end systems are replaced by NGN end systems and twisted copper lines are replaced by optical fibre, either fibre-to-the-curb (FTTC) or fibre-to-the-home (FTTH) to increase transmission speed. Figure 2-1: Migration of xDSL access to NGN 3 Signaling and control scenarios A possible scenario for migration of signalling in the core network consists of following three steps. • Step 1: In this step, signalling functions are transferred from the TEs to the independent units creating an STP mesh network (partial or complete). • Step 2: In this step, STPs are upgraded to the SGs and are placed on the edge between PSTN/ISDN and NGN. In this case, both the legacy network and NGN co-exist with each other. • Step 3: In this step, all LEs and TEs are replaced by NGN. Figure 3-1: Realization of signalling migration scenario 4 Services migration scenarios • Scenario 1: In this scenario, existing IN services are reused in NGN by implementing SSF in the CS. Both PSTN/ISDN and NGN Figure 4-1: Realization of scenario 1