1 IWF and CCF for VoIP Protocols Ming-Feng Chang Professor CSIE, NCTU

2 VoIP Voice over IP –transport of telephone calls using IP –telephony devices, multimedia PCs or dedicated terminals The benefits –a single infrastructure for Internet access and Internet telephony –saving money –easily integrated with other services and applications

3 The problems –lower quality of voice over IP higher delay and jitter –accounting, billing, charging, roaming etc. remain open –Interworking functions ISUP, Q.sig, H.323, SIP and MGCP/MEGACO

4 A Converged Network Architecture ICA – integrated call agent –A GK, SIP proxy server, and CA/MGC

5 The Interworking Functions PSTN –ISUP, Q.sig IP networks –H.323, SIP MGCP/MEGACO –Trunking gateways –Access gateways –Residential gateways Communication between any devices –The interworking function

6 Half-Call Call State Model of IN Originating FSM Terminating FSM –The switching system - an MGC or IWF

7 The Interactions of the FSMs 1. O_Null 2. Col_Info 3. Ana_Info 4. Routing 5. O_Active 1. T_Null 2. Sel_Fac 3. T_Alert 4. T_Active 6. O_Dis 5. T_Dis 7. O_Ab 1.Setup 2.Busy 4.NoAns 3.Alert 5.Answer 6.Disconnect 7.Disconnect 8.Abandon 8. O_Ex 6. T_Ex

8 The Interactions (Normal) 1. O_Null 2. Col_Info 3. Ana_Info 4. Routing 5. O_Active 1. T_Null 2. Sel_Fac 3. T_Alert 4. T_Active 6. O_Dis 5. T_Dis 7. O_Ab 1.Setup 3.Alert 5.Answer 6.Disconnect 7.Disconnect 8. O_Ex 6. T_Ex

9 The Interactions (Fail) 1. O_Null 2. Col_Info 3. Ana_Info 4. Routing 5. O_Active 1. T_Null 2. Sel_Fac 3. T_Alert 4. T_Active 6. O_Dis 5. T_Dis 7. O_Ab 2.Busy 4.NoAns 8. O_Ex 6. T_Ex

10 An Interworking Architecture We have developed half-call BCSMs –SIP, H.323, MGCP, and MEGACO Originating BCSMs Terminating BCSMs SIP O_BCSM SIP T_BCSM H.323 O_BCSM H.323 T_BCSM MGCP O_BCSM MGCP T_BCSM Events SIP Messages H.323 Messages MGCP Messages SIP Messages H.323 Messages MGCP Messages SIP user agent H.323 endpoint MGW SIP user agent H.323 endpoint MGW Originating BCSMs Terminating BCSMs SIP O_BCSM SIP T_BCSM H.323 O_BCSM H.323 T_BCSM MGCP O_BCSM MGCP T_BCSM Events SIP Messages H.323 Messages MGCP Messages SIP Messages H.323 Messages MGCP Messages SIP user agent H.323 endpoint MGW SIP user agent H.323 endpoint MGW

11 The Integrated IWF and CCF Integrate CA/MGC, GK and SIP proxy server MGCP OFSM H323 OFSM ISUP OFSM SIP OFSM MGCP TFSM H323 TFSM ISUP TFSM SIP TFSM Events busy alerted no answer answered disconnected abandoned suspend resume Q.931 OFSM Q.931 OFSM

12 SIP-H323 IWF SIP OFSM SIP TFSM H323 TFSM H323 OFSM Events busy alerted no answer answered disconnected abandoned The IWF for SIP and H.323 –A GK and SIP proxy server

13 VoIP Gateways H.323, SIP and MEGACO/MGCP

14 The Integrated CA Design MGCP OFSM MGCP TFSM SIP TFSM ISUP TFSM SIP OFSM H323 TFSM H323 OFSM ISUP OFSM

15 MGCP-SIP IWF/GW MGCP OFSM MGCP TFSM SIP TFSM SIP OFSM Inter-CA and intra-CA call setup Intra-CA Inter-CA

16 Inter-zone Communications Support inter-ICA call setup Media Gateway H.323 Zone SIP ICA H.323 O_BCSM SIP T_BCSM Zone ICA SIP O_BCSM MGCP T_BCSM Media Gateway H.323 Zone 1 SIP ICA 1 H.323 O_BCSM SIP T_BCSM Zone 2 ICA 2 SIP O_BCSM MGCP T_BCSM

17 MGCP Half-Call Model O_Null O_Collec_Info O_Routing O_Active O_Disconnect T_Null T_Present_Call T_Active T_Alerting T_Disconnect NTFY:HD RQNT NTFY:digits CRCX:reconly MDCX:RT MDCX:sendrec NTFY:HU DLCX CRCX:RG NTFY:HD MDCX: DLCX:E Setup Alert Answer Disconnect

18 H.323 Half-Call Model O_Null O_Collec_Info O_Routing O_Active O_Disconnect T_Null T_Present_Call T_Active T_Alerting T_Disconnect Setup CallProc Alert H.245 EX Release CallProc Connect H.245 EX Release Setup Alert Answer Disconnect Connect Alert Setup SDP

19 SIP Half-Call Model O_Null O_Collec_Info O_Routing O_Active O_Disconnect T_Null T_Present_Call T_Active T_Alerting T_Disconnect INVITE (SDP) 100 Trying 180 Ringing ACK BYE 100 Trying 200 OK (SDP) ACK BYE Setup Alert Answer Disconnect 200 OK (SDP) 180 Ringing INVITE (SDP) 200 OK

20 MEGACO Half-Call Model O_Null O_Collec_Info O_Routing O_Active O_Disconnect T_Null T_Present_Call T_Active T_Alerting T_Disconnect Notify:of Modify:digitmap,on NTFY:digits Add:rt,reconly Modify:sendrec,sdp2 Notify:on Add:ri,sendrec,sdp1 Notify:of Modify:,on Subtract:ct,on Setup(sdp1) Alert Answer(sdp2) Disconnect Reply:sdp1 Reply:sdp2 Subtract:of

21 MGW FSMs Media Gateways –Trunking GWs –Access GWs –Residential GWs OFSMs and TFSMs –For TGWs, AGWs, and RGWs

22 Examples Our VoIP platform

23 Examples Communications between any devices

24 Conclusions The interworking functions are important –ISUP, Q.sig, H.323, SIP and MGCP/MEGACO Half-call model –For the integrated IWF and CCF Gateway selection? –iptel Mobility support?