IWF and CCF for VoIP Protocols

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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

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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

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Half-Call Call State Model of IN

• Originating FSM
• Terminating FSM
• The switching system - an MGC or IWF

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The Interactions of the FSMs
7. O_Ab
1. O_Null
8. O_Ex
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
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The Interactions (Normal)
7. O_Ab
1. O_Null
8. O_Ex
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
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The Interactions (Fail)
7. O_Ab
1. O_Null
8. O_Ex
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
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An Interworking Architecture

• We have developed half-call BCSMs
• SIP, H.323, MGCP, and MEGACO

SIP
SIP
SIP Messages
SIP Messages
SIP
SIP
SIP Messages
SIP Messages
O_BCSM
T_BCSM
SIP user agent
O_BCSM
T_BCSM
SIP user agent
SIP user agent
SIP user agent
Events
Events
H.323
H.323
H.323 Messages
H.323 Messages
H.323
H.323
H.323 Messages
H.323 Messages
H.323 endpoint
H.323 endpoint
O_BCSM
T_BCSM
H.323 endpoint
O_BCSM
T_BCSM
H.323 endpoint
MGCP
MGCP
MGCP Messages
MGCP Messages
MGCP
MGCP
MGCP Messages
MGCP Messages
MGW
MGW
O_BCSM
T_BCSM
MGW
O_BCSM
T_BCSM
MGW
Originating
Terminating
Originating
Terminating
BCSMs
BCSMs
BCSMs
BCSMs
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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
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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

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VoIP Gateways

• H.323, SIP and MEGACO/MGCP

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The Integrated CA Design
SIP TFSM
MGCP OFSM
H323 TFSM
ISUP TFSM
SIP OFSM
MGCP TFSM
H323 OFSM
ISUP OFSM
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MGCP-SIP IWF/GW

• Inter-CA and intra-CA call setup

MGCP OFSM
SIP TFSM
Intra-CA
Inter-CA
MGCP TFSM
SIP OFSM
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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
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MGCP Half-Call Model
NTFYHD
O_Null
T_Null
RQNT
O_Collec_Info
T_Present_Call
NTFYdigits
CRCXRG
Alert
CRCXreconly
T_Alerting
Setup
NTFYHD
O_Routing
MDCXRT
MDCX
MDCXsendrec
T_Active
Answer
O_Active
NTFYHU
DLCXE
T_Disconnect
Disconnect
O_Disconnect
DLCX
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H.323 Half-Call Model
Setup
O_Null
T_Null
Setup
CallProc
O_Collec_Info
T_Present_Call
CallProc
Alert
Alert
Alert
T_Alerting
Setup
Connect
O_Routing
H.245 EX
T_Active
Answer
Connect
SDP
O_Active
H.245 EX
Release
T_Disconnect
Disconnect
O_Disconnect
Release
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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
T_Alerting
Setup
200 OK (SDP)
O_Routing
180 Ringing
ACK
T_Active
Answer
200 OK (SDP)
O_Active
ACK
BYE
BYE
T_Disconnect
Disconnect
O_Disconnect
200 OK
200 OK
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MEGACO Half-Call Model
Notifyof
O_Null
T_Null
Modifydigitmap,on
O_Collec_Info
T_Present_Call
NTFYdigits
Addri,sendrec,sdp1
Setup(sdp1)
Alert
Replysdp2
Addrt,reconly
T_Alerting
Notifyof
O_Routing
Replysdp1
Modify ,on
Modifysendrec,sdp2
Answer(sdp2)
T_Active
O_Active
Notifyon
Disconnect
Subtractct,on
T_Disconnect
O_Disconnect
Subtractof
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MGW FSMs

• Media Gateways
• Trunking GWs
• Access GWs
• Residential GWs
• OFSMs and TFSMs
• For TGWs, AGWs, and RGWs

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Examples

• Our VoIP platform

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Examples

• Communications between any devices

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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?