system management, the key exchange, investment and the service cost. The other option is to employ security services to the edge of the routers, the gateway, etc. With already quoted techniques and demands in terms of security, we sug- gest a physical structure for implementing a security platform of network and intelligent services in Figure 21.11 and Figure 21.12. SAO: Operator Server authorization. SOS: Service server authorization. SAC: Service Access Code C 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security 18- Ti 19- ACK/NACK 14- (To,MAC) Operator server authorization 17.T1 13- (To, MAC) 16- Ti 20- INVITE Service server authorization 21 -200 OK 15- (To,MAC) 12- (To, MAC) 1 INVITE 2- Authentication 3- INVITE 22-200 OK 8- (SAC, PIN, ID)? SIP Server 9- (SAC, PIN,ID) 11 (To, MAC) 7- (SAC, PIN, ID) ? SIP Client 10- (SAC, PIN, ID) 4- INVITE 5- Conversation Firewall 6- (SAC, PIN,ID) ? VoiceXML Browser Web service FIGURE 21.11 Service telecommunication security with SIP. PIN: Personal Identification Number ID: User ID To: Operator Ticket MAC: Message Authentication Code Ti: Service Ticket F1: SIP INVITE with authentication and ID F2: 407 Authentication Proxy F3: ACK F4: INVITE a session with a service C 2009 by Taylor & Francis Group, LLC Secure Intelligent SIP Services FIGURE 21.12 Diagram of intelligent network secure. F5: http://service1.dialog.vxml [9] F6: Give your identifiers (SAC, PIN, ID) F7: Give your identifiers (SAC, PIN, ID) F8: Give your identifiers (SAC, PIN, ID) F9: Here is my identifiers F10: calculation of To and MAC F11: To and MAC transmitted to SSP F12: then to SCP F13: validation or no F14: If validated ; send to SOS F15: calculation of Ti F16: Ti to SCP F17: verification of Ti by SOA F18: Validation or not of Ti F19: If validated, interrogate SSP. F20: INVITE F21: OK. © 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security 21.5 Conclusion The approach of integration of SIP and IN permits the use of intelligent services alrea