Transcript 新世代網際電話標準與架構剖析

Introduction to SIP Based
ENUM IP Telephony Infrastructure
資策會 網路及通訊實驗室
Conference over IP Team
楊政遠 博士
[email protected]
Outline
• Review
• The Next Generation Converged
Network
• SIP based IP Telephony System
• Integrate ENUM with SIP Based IP
Telephony system
• The first run of SIP project in III NCL
Review
• PSTN
– Signaling: System Signal No: 7
– Carrier: T1 and successors …...
Signaling plane
STP
CO
Bearer plane
CPE
Local loop
DTMF
Review
• Internet (IP) Phone
1. ?
2. Call setup signaling
AD/DA
compress/decompress
3. Digital voice packets
AD/DA
compress/decompress
Review
(cont.)
• Telephony Issues
– Signaling
• Addressing
– PSTN - SS7 (ITU E.164)
– VoIP - H.323、SIP、MGCP、Megaco/H.248
• Capability exchange
– PSTN - Analog voice / -law、A-law PCM
– VoIP - Digital voice / G.711、G.723.1 、G.729
Review
(cont.)
• Telephony Issues
– Bearer
• Transport
– PSTN - TDM T1 trunk
– VoIP - RTP over UDP/IP
• Delay and Jitter
– PSTN - circuit switching / propagation delay
– VoIP - packet switching / unbounded delay and jitter
– Internetworking between PSTN & IP Telephony
Next Generation Converged Network
softswitch
Signaling
gateway
Media
gateway
controllor
SIP-T
SIP-T
MGCP
MEGACO/H.248
SCP
Signaling
gateway
Softswitch
SIP¡BMGCP¡B
MEGACO/H.248
MGCP¡B
MEGACO/H.248
MGCP/SIP
phone
Trunk
gateway
PSTN
SSP
softswitch
SIP-T
Trunk
gateway
STP
Media
gateway
controllor
Internet
Residential
gateway
SCP
STP
PSTN
SSP
POTS
POTS
analogy
phone set
SIP based IP Telephony System
SIP BASIC Call flow
Caller
Pickup & dial
Callee
INVITE SIP:[email protected] SIP/2.0
…….
Ringing
180, Ringing
Pick up
200, OK
ACK
RTP (voice)
On-hook
BYE
ACK
SIP based IP Telephony System
SIP Distributed Architecture
SIP Components
Location
Server
Redirect
Server
Registrar
Server
PSTN
User Agent
Gateway
Proxy
Server
Proxy
Server
SIP based IP Telephony System
SIP proxy server
Location server
?
INVITE sip:[email protected] SIP/2.0
…….
User Agent
INVITE sip:[email protected] SIP/2.0
…….
Proxy server
Maybe rewrite SIP
request
Proxy servers are, for example, used to route requests,
enforce policies, control firewalls.
SIP based IP Telephony System
SIP redirect server
Location server
Proxy server
or caller
INVITE sip:[email protected] SIP/2.0
………….
302 moved temporarily
contract …….
?
redirect server
ACK
INVITE sip:[email protected] SIP/2.0
…….
Unlike a proxy server, it does not initiate its own SIP request.
Unlike a user agent server, it does not accept call.
Simple SIP call setup and teardown
Proxy Server
User Agent
INVITE
Location/Redirect Server
INVITE
302
(Moved Temporarily)
User Agent
Proxy Server
ACK
INVITE
INVITE
302
(Moved Temporarily)
ACK
Call
Setup
180 (Ringing)
200 (OK)
ACK
Media
Path
Call
Teardown
180 (Ringing)
200 (OK)
ACK
INVITE
180 (Ringing)
200 (OK)
ACK
RTP MEDIA PATH
BYE
BYE
BYE
200 (OK)
200 (OK)
200 (OK)
SIP based IP Telephony System
• SIP based IP Telephony System must
support
Feature and
Application Creation
Operation
System Support
SIP Based Call Control and Switching
SIP based IP Telephony System
PSTN
Internet
Gateway
SIP proxy Server
SIP proxy Server
Provisioning
Server(s)
SNMP
Network
Manager
Feature
Server(s)
SIP based
CDR
Server(s)
RADIUS
H.323/SIP
Translator
SIP proxy Server
H.323
Terminal
Clearing
House
MGCP/SIP
Translator
SIP proxy Server
SIP IP Phone
SIP proxy Server
3rd Party Billing
System
MGCP Device
VOCAL System [http://www.vovida.org/
SIP based IP Telephony System
H.323 Translator: Acts as a Gatekeeper to control H.323 endpoints.
Talks SIP to the rest of the network for routing and features.
SIP based IP Telephony System
MGCP Translator: Acts as a call agent to control
MGCP end points. Talks SIP to the rest of the network
for routing and features.
SIP based IP Telephony System
SIP proxy Server: Acts as a trusted boundary for calls entering or
leaving a network. Provides authentication and collects
billing information for the CDR server.
SIP based IP Telephony System
CDR Server: Collects billing information from
Marshal Servers and interfaces with billing systems using
the RADIUS accounting protocol.
SIP based IP Telephony System
Provisioning Server: Used to provision, configure and
manage subscribers and servers from a GUI.
SIP based IP Telephony System
Feature Server: Provide CPL based or XML scripts that
run basic telephony features.
SIP based IP Telephony System
Basic call initiation
1. Invite
SIP Phone
SIP proxy server
2. Invite
3. Invite
SIP proxy server
SIP Phone
SIP based IP Telephony System
Basic call establishment
6. 180, Ringing
9. 200, OK
10. ACK
5. 180, Ringing
8. 200, OK
SIP proxy server 11. ACK
4. 180, Ringing
7. 200, OK
SIP proxy server 12. ACK
13. RTP
SIP Phone
SIP Phone
SIP based IP Telephony System
Basic call tear down
Redirect
16. BYE
15. BYE
17. 200, OK
14. BYE
18. 200, OK
SIP proxy server
19. 200, OK
SIP proxy server
20. Tear down RTP
SIP Phone
SIP Phone
SIP based IP Telephony System
• Operation System Support (OSS)
includes
– Provision
• adding and maintaining network users
– Authentication
• Access list / Digest
– Billing
– Network management
SIP based IP Telephony System
Billing (CDR ends to record)
17. BYE
15. BYE
13. BYE
19. 200, OK
20. 200, OK
SIP Proxy
SIP Proxy
18. 200, OK
16. Notify for end record
14. Notify for end record
CDR server
21. Tear down RTP
SIP Phone
SIP Phone
SIP based IP Telephony System
• Feature services are the value-added functions of the
phone system
– Core features
• Calling Information
– Calling Number Delivery (CND) or Calling Line Identification
(CLID) / Calling Party Identity Blocking (CIDB)
• Calling Forwarding
– Forward All Calls (CFA) / Forward - No Answer Mode (CFNA) /
Forward - Busy Mode ( CFB )
• Call Blocking / Call Screening
– Set features
• Call transfer / Call Return / Call waiting / Cancel Call Waiting ( CCW )
– Scriptable features
• Call Processing Language (CPL)
SIP based IP Telephony System
Features service - call blocking
2. Invite
Redirect
4. ACK
3. 320, move ...
2. Invite
1. Invite
3. 403, Forbidden
SIP proxy
5, 403 Forbidden
SIP Phone
4. ACK
Call blocking
feature server
ENUM SIP Based Telephony system
SIP phone to PSTN
2. ENUM DNS Query
3. NAPTR RR
ENUM DNS
1. Invite
4. Front End Protocols
5. Gateway location
SIP Proxy
Clearinghouses
6. Invite
Gateway
SIP Phone
7. Invite
Gateway
SIP proxy
11. PSTN
ENUM SIP Based Telephony system
PSTN to SIP phone
1. ENUM Query
ENUM DNS
2. NAPTR RR
3. DNS Query
4. A RR
5. Invite
Softswitch
SIP proxy
STP
6. Invite
SCP
SSP
PSTN
Media
Gateway
SIP proxy
7. Invite
DNS
ENUM SIP Based Telephony system
PSTN to SIP phone
SIP proxy
16. 180, Ringing
ENUM DNS
19. 200, OK
20. ACK
DNS
21. ACK
Softswitch
18. 200, OK
STP
SCP
SSP
SIP proxy
PSTN
23. voice
15. 180, Ringing
Media
Gateway
22. ACK
23. RTP
14. 180, Ringing
17. 200, OK
Thanks !