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IWF and CCF for VoIP Protocols. Ming-Feng Chang Professor CSIE, NCTU. 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
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IWF and CCF for VoIP Protocols Ming-Feng Chang Professor CSIE, NCTU
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
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
A Converged Network Architecture • ICA – integrated call agent • A GK, SIP proxy server, and CA/MGC
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
Half-Call Call State Model of IN • Originating FSM • Terminating FSM • The switching system - an MGC or IWF
8.Abandon 1.Setup 2.Busy 3.Alert 4.NoAns 5.Answer 6.Disconnect The Interactions of the FSMs 7. O_Ab 8. O_Ex 1. O_Null 1. T_Null 6. T_Ex 2. Col_Info 2. Sel_Fac 3. Ana_Info 3. T_Alert 4. Routing 4. T_Active 5. O_Active 5. T_Dis 7.Disconnect 6. O_Dis
1.Setup 3.Alert 5.Answer 6.Disconnect 7.Disconnect The Interactions (Normal) 7. O_Ab 8. O_Ex 1. O_Null 1. T_Null 6. T_Ex 2. Col_Info 2. Sel_Fac 3. Ana_Info 3. T_Alert 4. Routing 4. T_Active 5. O_Active 5. T_Dis 6. O_Dis
2.Busy 4.NoAns The Interactions (Fail) 7. O_Ab 8. O_Ex 1. O_Null 1. T_Null 6. T_Ex 2. Col_Info 2. Sel_Fac 3. Ana_Info 3. T_Alert 4. Routing 4. T_Active 5. O_Active 5. T_Dis 6. O_Dis
An Interworking Architecture • We have developed half-call BCSMs • SIP, H.323, MGCP, and MEGACO SIP Messages SIP Messages SIP SIP SIP SIP SIP Messages SIP Messages SIP user agent SIP user agent O_BCSM O_BCSM T_BCSM T_BCSM SIP user agent SIP user agent Events Events H.323 Messages H.323 Messages H.323 H.323 H.323 H.323 H.323 Messages H.323 Messages H.323 endpoint H.323 endpoint O_BCSM O_BCSM T_BCSM T_BCSM H.323 endpoint H.323 endpoint MGCP Messages MGCP Messages MGCP MGCP MGCP MGCP MGCP Messages MGCP Messages MGW MGW O_BCSM O_BCSM T_BCSM T_BCSM MGW MGW Originating Originating Terminating Terminating BCSMs BCSMs BCSMs BCSMs
The Integrated IWF and CCF • Integrate CA/MGC, GK and SIP proxy server Q.931 OFSM Q.931 OFSM • Events • busy • alerted • no answer • answered • disconnected • abandoned • suspend • resume MGCP OFSM MGCP TFSM SIP OFSM SIP TFSM H323 OFSM H323 TFSM ISUP OFSM ISUP TFSM
SIP-H323 IWF • The IWF for SIP and H.323 • A GK and SIP proxy server SIP OFSM H323 TFSM SIP TFSM H323 OFSM • Events • busy • alerted • no answer • answered • disconnected • abandoned
VoIP Gateways • H.323, SIP and MEGACO/MGCP
The Integrated CA Design SIP TFSM MGCP OFSM H323 TFSM ISUP TFSM SIP OFSM MGCP TFSM H323 OFSM ISUP OFSM
MGCP-SIP IWF/GW • Inter-CA and intra-CA call setup MGCP OFSM SIP TFSM Intra-CA Inter-CA MGCP TFSM SIP OFSM
Zone 1 Zone 2 ICA 1 ICA 2 SIP H.323 SIP SIP MGCP O_BCSM T_BCSM O_BCSM T_BCSM H.323 Inter-zone Communications • Support inter-ICA call setup Zone Zone ICA ICA SIP H.323 SIP SIP MGCP O_BCSM T_BCSM O_BCSM T_BCSM Media Media Gateway Gateway H.323
MGCP Half-Call Model NTFY:HD RQNT O_Null T_Null NTFY:digits O_Collec_Info T_Present_Call CRCX:RG Alert CRCX:reconly Setup T_Alerting NTFY:HD O_Routing MDCX:RT MDCX: MDCX:sendrec Answer T_Active NTFY:HU O_Active DLCX:E Disconnect T_Disconnect DLCX O_Disconnect
H.323 Half-Call Model Setup O_Null T_Null Setup CallProc O_Collec_Info T_Present_Call CallProc Alert Alert Alert Setup T_Alerting Connect O_Routing H.245 EX Answer T_Active Connect SDP H.245 EX O_Active Release Disconnect T_Disconnect Release O_Disconnect
SIP Half-Call Model INVITE (SDP) 100 Trying O_Null T_Null INVITE (SDP) 100 Trying O_Collec_Info T_Present_Call 180 Ringing Alert Setup T_Alerting 200 OK (SDP) O_Routing 180 Ringing ACK Answer T_Active 200 OK (SDP) O_Active ACK BYE BYE Disconnect T_Disconnect O_Disconnect 200 OK 200 OK
MEGACO Half-Call Model Notify:of Modify:digitmap,on O_Null T_Null NTFY:digits O_Collec_Info Setup(sdp1) T_Present_Call Add:ri,sendrec,sdp1 Alert Reply:sdp2 Add:rt,reconly T_Alerting Notify:of O_Routing Reply:sdp1 Modify: ,on Modify:sendrec,sdp2 Answer(sdp2) T_Active Notify:on O_Active Disconnect Subtract:ct,on T_Disconnect Subtract:of O_Disconnect
MGW FSMs • Media Gateways • Trunking GWs • Access GWs • Residential GWs • OFSMs and TFSMs • For TGWs, AGWs, and RGWs
Examples • Our VoIP platform
Examples • Communications between any devices
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?