introduction to sip based enum ip telephony infrastructure

Introduction to SIP Based Introduction to SIP Based ENUM IP Telephony InfrastructureENUM IP Telephony Infrastructure

資策會網路及通訊實驗室資策會網路及通訊實驗室 Conference over IP TeamConference over IP Team

楊政遠博士楊政遠博士[email protected]

OutlineOutline

• 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

ReviewReview• PSTN

– Signaling: System Signal No: 7– Carrier: T1 and successors …...

STP

Local loop

DTMF

Signaling plane

Bearer plane

CPE

CO

ReviewReview

• Internet (IP) Phone

1. ?

3. Digital voice packets

2. Call setup signaling

AD/DA compress/decompress

AD/DA compress/decompress

Review Review (cont.)(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 Review (cont.)(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 NetworkNext Generation Converged Network

T ru n kg a te w a y

PSTN

M e d iag a te w a y

c o n tro llo r

PSTNInternet

T ru n kg a te w a y

S ig n a lin gg a te w a y

M G C PM E G A C O /H .2 4 8

STP

SCP

SSPSSP

S ig n a lin gg a te w a y

M e d iag a te w a y

c o n tro llo r

STP

SCP

PO TS

PO TS

M G C P /S IPp h o n e

S o ftsw itc h

softsw itchsoftsw itch

ana logyphone se t

R e s id e n tia lg a te w a y

S IP ¡B M G C P ¡BM E G A C O /H .2 4 8

M G C P ¡BM E G A C O /H .2 4 8

S IP -T

S IP -T

S IP -T

SIP based IP Telephony SystemSIP based IP Telephony System

INVITE SIP:[email protected] SIP/2.0…….

180, Ringing

200, OK

ACKRTP (voice)

BYE

ACK

Caller CalleePickup & dial

Ringing

Pick up

On-hook

SIP BASIC Call flow


Redirect Server

Location Server

Registrar Server

User Agent

Proxy Server

Gateway

PSTN

SIP Components

Proxy Server

SIP Distributed ArchitectureSIP Distributed Architecture

SIP proxy serverSIP proxy server

INVITE sip:[email protected] SIP/2.0…….

Proxy server


Maybe rewrite SIP request

Location server

?

User Agent

Proxy servers are, for example, used to route requests, enforce policies, control firewalls.


redirect server

Location server

?

Proxy serveror caller

INVITE sip:[email protected] SIP/2.0………….

302 moved temporarilycontract …….


ACK

Unlike a proxy server, it does not initiate its own SIP request.Unlike a user agent server, it does not accept call.

SIP redirect serverSIP redirect server


Simple SIP call setup and teardownSimple SIP call setup and teardown

302 (Moved Temporarily)

INVITE

200 (OK)200 (OK)

ACK

INVITE302

(Moved Temporarily)ACK

INVITE

180 (Ringing)180 (Ringing)180 (Ringing)

200 (OK)ACKACK ACK

RTP MEDIA PATH

BYEBYE BYE

200 (OK)200 (OK) 200 (OK)Call Teardown

MediaPath

Call Setup

INVITE

Location/Redirect ServerProxy Server Proxy Server User AgentUser AgentINVITE


• SIP based IP Telephony System must support

SIP Based Call Control and Switching

Operation System Support

Feature and Application Creation


CDR Server(s)

Feature Server(s)

Provisioning Server(s)

3rd Party Billing System

RADIUS

SNMP NetworkManager

ClearingHouse

Internet

SIP proxy ServerSIP proxy Server

PSTN

Gateway

SIP proxy Server

SIP IP Phone MGCP Device

MGCP/SIPTranslator

SIP proxy Server

H.323/SIP Translator

SIP proxy Server

H.323 Terminal

SIP based

VOCAL System [http://www.vovida.org/

H.323 Translator: Acts as a Gatekeeper to control H.323 endpoints.Talks SIP to the rest of the network for routing and features.


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 SystemSIP based IP Telephony SystemSIP proxy Server: Acts as a trusted boundary for calls entering or leaving a network. Provides authentication and collects billing information for the CDR server.

CDR Server: Collects billing information from Marshal Servers and interfaces with billing systems using the RADIUS accounting protocol.


Provisioning Server: Used to provision, configure and manage subscribers and servers from a GUI.


Feature Server: Provide CPL based or XML scripts that run basic telephony features.


SIP proxy server

1. Invite2. Invite 3. Invite

SIP Phone SIP Phone

Basic call initiationBasic call initiation


SIP proxy server

Basic call establishmentBasic call establishment

4. 180, Ringing5. 180, Ringing6. 180, Ringing

7. 200, OK8. 200, OK9. 200, OK

10. ACK 11. ACK 12. ACK

13. RTP

SIP Phone SIP Phone



Basic call tear downBasic call tear down

Redirect

14. BYE15. BYE16. BYE

18. 200, OK17. 200, OK 19. 200, OK

20. Tear down

SIP Phone SIP Phone

RTP



• Operation System Support (OSS) includes– Provision

• adding and maintaining network users

– Authentication• Access list / Digest

– Billing– Network management


Billing (CDR ends to record)Billing (CDR ends to record)

SIP Proxy

13. BYE15. BYE17. BYE

18. 200, OK

19. 200, OK 20. 200, OK

SIP PhoneSIP Phone

CDR server

16. Notify for end record 14. Notify for end record

21. Tear down RTP

SIP Proxy


• 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)


Features service - call blockingFeatures service - call blocking

SIP proxyCall blockingfeature server

Redirect

SIP Phone

1. Invite

2. Invite

4. ACK

3. 320, move ...

2. Invite

3. 403, Forbidden

4. ACK

5, 403 Forbidden


ENUM SIP Based Telephony systemENUM SIP Based Telephony system

GatewaySIP proxy

SIP Proxy

SIP Phone

1. Invite

7. Invite

11. PSTN

Gateway

ENUM DNS

2. ENUM DNS Query

3. NAPTR RR

4. Front End Protocols

Clearinghouses

5. Gateway location

SIP phone to PSTNSIP phone to PSTN

6. Invite


PSTN to SIP phonePSTN to SIP phone

SSP

SCPPSTN

STPSoftswitch

Media Gateway

ENUM DNS1. ENUM Query

2. NAPTR RR DNS3. DNS Query

4. A RR

SIP proxy

5. Invite

6. Invite

7. InviteSIP proxy


PSTN to SIP phonePSTN to SIP phone

SSP

SCPPSTN

STPSoftswitch

Media Gateway

15. 180, Ringing

14. 180, Ringing

SIP proxy

SIP proxy16. 180, Ringing

17. 200, OK

18. 200, OK

19. 200, OK

20. ACK

21. ACK

22. ACK

DNS

ENUM DNS

23. RTP

23. voice

Thanks !Thanks !

introduction to sip based enum ip telephony infrastructure

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