Vorlage 3b

destination address is the same for both of the redundant LEMF systems. The CSP cannot detect which side of the LEMF is currently active.

ISDN Interconnection ISDN PRA CSP 1 Interface with SS # 7 30x64 kbit/s plus 64 kbit/s DSS1 N IIF/MD E IIF/MD N Network LEMF ProductionIIF/MD ProductionIIF/MD E Element Production Production N Production E ISDN Delivery Network CSP 2 N IIF/MD N Network LEMF E IIF/MD E Element Production ProductionIIF/MD ProductionIIF/MD Production N Production E DN-HP LI-HP non-coincident

Figure 7 Delivery network for Content of Communication of circuit-switched services

The content (CC) of CS interceptions is transferred by the CSP via the usual interconnect interfaces to the universal service licensee. The interconnection documents are on the universal service licensee’s website.

The LEMF has a redundant connection to the telephone network (PSTN) of the universal service licensee. It is not planned that CSP build direct PRA terminations to the LEMF (with the exception of the universal service licensee).

The PRAs at both LEMF sites are connected to two geographically separate telephone switches. Together with other redundancy measures, this guarantees a very high level of reliability.

The delivery network itself does not take any recovery action if the set-up of a CC connection fails or if a CC connection is released by the delivery network or the LEMF. Such action shall be initiated by the MF of the CSP.

If a CSP does not have an interconnect interface to the universal service licensee, it shall establish an interconnection via other providers.

Figure 8 shows the handover points and areas of responsibility in the ISDN delivery network for delivery of Content of Communication from circuit-switched services (CS CC). This delivery network corresponds to the basic topology of a “concatenated delivery network” as per Figures 5 and 6.

The handover point between the CSP and the PTSS for LI formats, i.e. the calling und called party subaddress for setting up CC links (LI-HP) and the CSP’s handover point for transportation (DN-HP) are not coincident. A triangular relationship thus exists between the LI-HP and two DN-HPs (between the CSP and the ISDN-DN Provider and between the ISDN-DN Provider and the PTSS).