e preferable. To start with the packet services will be 'best effort' services. Both point-to-point and point-to-multipoint services will be possible. A packet mode path will offer a shared bearer up to 2 Mbit/s. Initially the maximum bit rate will be 384 kbit/s (interactive RAB up to 384 kbit/s). 8.10.1 ORIGINATING WCDMA/UMTS CALL TO PSTN Figure 8.40 shows an example of a real-time service call set-up in UMTS 1. The user equipment requests a call set-up and sends the call requirements (bearer type, codec, B-number). 2. Based on the B-number the MSC/VLR server selects MGW. 3. The MSC server sends CALL PROCEEDING including the selected codec back to RNC. 4. The MSC server creates a termination T1 in MGW (properties: AAL2, AMR, Con- text1). Termination here means that the MGW creates links between this call and its own seized resources. All connectivity layer resources assigned to this call are linked together. If another MGW is interconnected the linked resources there will be treated independently. 5. The MSC server orders the RAB assignment. 6. RNC establishes the bearer to the MGW. 7. Notification from RNC to MSC that RAB is established (assignment complete). Add new termination T2 (properties: PCM, AAL2, Context1). MGW links in a transcoder, because of different coding (AMR/PCM) in T1 and T2. MSC server sends BICC IAM (initial address message) with B-number and MGW1 to TSC server. BICC 9 server server server server N-ISUP 10,11,14 Q.AAL2 RANAP/"DTAP" 1,3,5,7 12,13 ATM or IP connectivity UTRAN PSTN/ISDN network Circuit/STM TDM NETWORK Possibly collocated functions Figure 8.40 Example of a real-time service call set-up in UMTS Understanding Changing Telecommunications - Building a Successful Telecom Business 8. The TSC server creates a new termination T3 with properties PCM, AAL2, and new context and connects to termination T2. 9. The TSC server creates termination T4. 10. The IAM is sent to the external network. 11. The ACM (address complete message) is received from the external network. 12. The TSC server lin