1Nable Communications, Inc.
IP Multimedia Subsystem(IMS) and Its Applications
2007. 4. 262007. 4. 26
JunJun--Won LeeWon LeeNableNable Communications, Inc.Communications, Inc.
KNOM Conference April 26 ~ 27 2007KNOM Conference April 26 ~ 27 2007
2Nable Communications, Inc.
Contents
ContentsContents
IMS OverviewIMS Overview
IMS ArchitectureIMS Architecture
IMS ApplicationsIMS Applications
IMS Enablers & ClientsIMS Enablers & Clients
3Nable Communications, Inc.
IMS Overview
• IP Multimedia Subsystem (IMS) – An architectural framework for delivering IP multimedia services to
end users, originally designed by 3GPP– At the heart of Next Generation Convergent Networks
Pre-IMS Communications(Service Islands)
PrePre--IMS CommunicationsIMS Communications(Service Islands)(Service Islands)
IMS Communications(Integrated Services)
IMS CommunicationsIMS Communications(Integrated Services)(Integrated Services)
4Nable Communications, Inc.
IMS Overview – Network Convergence
IMSIMS
FIXEDFIXED MOBILEMOBILE
Serv
ices
Core
AccessCon
nect
ivity
Use
r
HSSHSS
Services Location/Auth
WCDMAGERANWiMAX WLANxDSL
5Nable Communications, Inc.
IMS Overview - What IMS Provides
• Services and Control– Adds call session control to the packet network – Enables peer-to-peer real-time services - such as voice, video -
over a packet-switched domain
• Mixed Multimedia– Ability to pick and mix various multimedia flows in single or multiple
sessions– Can handle real-time voice, video, data
• Connectivity Independence– Provides access to IP based services independent of the
connectivity network: mobile (3GPP’s UMTS, 3GPP2’s CDMA2000) and fixed networks (TISPAN’s NGN)
6Nable Communications, Inc.
IMS Overview - Standards
• 3GPP has developed IMS for delivering “Internet Services” over GPRS• 3GPP2 is defining requirements for support of CDMA2000• TISPAN is defining the NGN network based on 3GPP IMS and
adapting 3GPP IMS to fixed access networks• OMA is defining services based on the 3GPP IMS service platform• IETF standards such as SIP is fully utilized for IMS to ease the
integration with the Internet
3GPP : 33GPP : 3rdrd Generation Partnership ProjectGeneration Partnership ProjectTISPAN : Telecom & Internet converged Services & Protocols for ATISPAN : Telecom & Internet converged Services & Protocols for Advanced Networkdvanced NetworkOMA : Open Mobile AllianceOMA : Open Mobile Alliance
7Nable Communications, Inc.
IMS Overview – SIP centerred
8Nable Communications, Inc.
Contents
ContentsContents
IMS OverviewIMS Overview
IMS ArchitectureIMS Architecture
IMS ApplicationsIMS Applications
IMS Enablers & ClientsIMS Enablers & Clients
9Nable Communications, Inc.
IMS Architecture - Overall
10Nable Communications, Inc.
IMS Architecture - Simplified
11Nable Communications, Inc.
IMS Architecture – Major Components
• HSS (Home Subscriber Server)– UPSF (User Profile Server Function)– Master user database
• Subscription-related information (user profiles)
– Performs authentication and authorization – Provides information about the physical location of user
• SLF (Subscriber Location Function)– Map user addresses when multiple HSSs are used
12Nable Communications, Inc.
IMS Architecture – Major Components
– User Identities• IMSI (International Mobile Subscriber Identity) : a unique user identity that is
stored in the SIM• TMSI (Temporary Mobile Subscriber Identity) : To improve privacy, a TMSI is
generated per geographical location. IMSI/TMSI are used for user identification. • IMEI (International Mobile Equipment Identity) : a unique device identity • MSISDN (Mobile Subscriber ISDN Number) : telephone number of a user
– Additional Identities with IMS• IMPI (IP Multimedia Private Identity) : a tel-uri or sip-uri. Unique to the phone.
More than one IMPU per IMPI• IMPU (IP Multimedia Public Identity) : a tel-uri or sip-uri. IMPU can be shared
with another phone. Both the phone can be reached with the same identity
NoteNoteNote
13Nable Communications, Inc.
IMS Architecture – Major Components
• P-CSCF (Proxy Call Session Control Function)– First point of contact for the IMS client– Assigned to an IMS terminal during registration, and does not change for
the duration of the registration – Sits on the path of all signalling messages, and can inspect every message – Authenticates the user and establishes an IPsec security association with
the IMS terminal. This prevents spoofing attacks and replay attacks and protects the privacy of the user. Other nodes trust the P-CSCF, and do not have to authenticate the user again.
– Compress and decompress SIP messages using SigComp, which reduces the round-trip over slow radio links
– May include a PDF (Policy Decision Function), which authorizes media plane resources e.g. quality of service (QoS) over the media plane. It's used for policy control, bandwidth management, etc ... The PDF can also be a separate function.
– Generates charging records
14Nable Communications, Inc.
IMS Architecture – Major Components
• S-CSCF (Serving CSCF)– Central node of the signaling plane– Uses DIAMETER to talk with HSS to download and upload user
profiles. No local storage for the user– Handles SIP registration thus binding the user location(IP addr) and
the SIP address– Decides to which application servers the SIP message will be
forwarded– Routing service using ENUM lookups– Multiple S-CSCF for load distribution and high availability reasons
15Nable Communications, Inc.
IMS Architecture – Major Components
• I-CSCF (Interrogating CSCF)– At the edge of an administrative domain– A forwarding point for SIP packets to other domain– THIG (topology hiding inter-network gateway) function
• From Rel7, this function is transferred to a new entity, IBCF(InterconnectionBorder Control Function)
16Nable Communications, Inc.
IMS Architecture – Major Components
• Application Servers– Host and execute services– Interfaces with the S-CSCF (ISC interface)– Example services
• Caller ID, Call waiting, Call forwarding, Call transfer, Call hold, Call pickup• Conference call• Voice mail, Unified Messaging• Text-to-speech, Speech-to-text• Push-to-talk (PTT)• Location based services• Presence, Instant Messaging• Voice Call Continuity (VCC)• Etc.
– Types• SIP AS : native IMS application server• OSA-SCS(Open Service Access – Service Capability Server) : interface with OSA
application servers using Parlay• IM-SSF(IP Multimedia Service Switching Function) : interface with CAMEL application
servers using CAP
17Nable Communications, Inc.
IMS Architecture – Major Components
• MRF (Media Resource Function)– Used for
• Playing of announcement (audio/video)• Multimedia conferencing • Text-to-speech and speech recognition• Real-time transcoding of multimedia data
– MRFC (Media Resource Function Controller)• Signaling plane node• Controls MRFP with a H.248 interface
– MRFP (Media Resource Function Processor)• Media plane node
18Nable Communications, Inc.
IMS Architecture – Major Components
• BGCF (Breakout Gateway Control Function)– Routing functionality based on telephone numbers
• SGW (Signaling Gateway)– Transforms lower layer protocols (SCTP into MTP)– Pass ISUP from MGCF to the CS network
• MGCF (Media Gateway Controller Function)– Protocol conversion between SIP and ISUP– Interfaces with SGW over SCTP– Controls resources in an MGW with a H.248
• MGW (Media Gateway)– Converting between RTP and PCM– Transcoding
19Nable Communications, Inc.
IMS Architecture – REGISTER Flows
20Nable Communications, Inc.
IMS Architecture – Session Setup Flows (1)
21Nable Communications, Inc.
IMS Architecture – Session Setup Flows (2)
22Nable Communications, Inc.
IMS Architecture – Session Setup Flows (3)
RTP
23Nable Communications, Inc.
Contents
ContentsContents
IMS OverviewIMS Overview
IMS ArchitectureIMS Architecture
IMS ApplicationsIMS Applications
IMS Enablers & ClientsIMS Enablers & Clients
24Nable Communications, Inc.
IMS Applications - PoC
• PoC (Push-to-Talk over Cellular)– a walkie-talkie type service that
provided over a cellular phone network
– half duplex communications —while one person speaks, the other(s) listen
– Immediate and instant communication
– Video and text as well as voice– Open standard-based (OMA)
25Nable Communications, Inc.
IMS Applications - Video Sharing
• Video Sharing– Sharing one-way live video or
video clips in real time during a normal voice call
– Enhances a voice call with the ability to share video among users
• New opportunity for mobile operators to gain additional revenue from voice calls
• Prolonged voice call duration
– Open standard based (GSMA)
26Nable Communications, Inc.
IMS Applications – Video Sharing
(From Nokia(From Nokia’’s WP)s WP)
27Nable Communications, Inc.
IMS Applications – VCC (Voice Call Continuity)
Wi-FiAccess
IP CoreNetwork
IMS Core
VCC AS
MSC
MGWMGCF
CDMA 1x
Handover
Dual-BandHandset Device
OEP(other end point)
OEPWiBro
1x
Anchoring and Switching at VCC AS1) Basic Concept of VCC1) Basic Concept of VCC
28Nable Communications, Inc.
IMS Applications – VCC (Voice Call Continuity)
PS
CS
[2]
[4’]
[3]
[7][5]
• Call Flows
[1] Call Origination
[2] ISUP:IAM
[3] SIP:INVITE
[4] SIP:200 OK
[5] ISUP:ANM
[6] 1x TCH Setup
[7] SIP:ACK
[8] SIP:BYE
[9] SIP:200 OK
[3’]
UE
{ckt} {pkt}
[1]
MGCF + MGW
[9][8]
IMS Core + VCC AS
[4] [7’]
OTHER END POINT
[6]
MSC/VLR
2) Signal Flow for 2) Signal Flow for VoIPVoIP to CDMA Handto CDMA Hand--Over Over
29Nable Communications, Inc.
Contents
ContentsContents
IMS OverviewIMS Overview
IMS ArchitectureIMS Architecture
IMS ApplicationsIMS Applications
IMS Enablers & ClientsIMS Enablers & Clients
30Nable Communications, Inc.
Overall IMS Architecture
WiBro
WiFi
IMS ClientsIMS Clients
xDSL
CDMA
MRF
MGCF
IMS Enablers (or Application Servers)IMS Enablers (or Application Servers)
IMS CoreIMS Core
HSDPA
IMIMPresencePresence VCCVCC PoCPoC
MRFCMRFC SS--CSCFCSCF
II--CSCFCSCF
PP--CSCFCSCF
BGCFBGCF
MGCMGC SGWSGW
MGWMGW
MRFPMRFP
HSSHSS
SLFSLF
Video ShareVideo SharePortable toPortable toAny DeviceAny Device
PSTN/PLMNManaged IP NetworkManaged IP Network
31Nable Communications, Inc.
OMA Perspectives
Voice
MessagingSMS,MMS
IMPush2X(show/video)
PersonalizedContents
LBSTelematics
PIMS
Broadcast, Music
M-game
Avatar, Ringtone
M-bankingTrading
PaymentPurchasing
Communication
Information
Entertainment
Finance
• Trend of Mobile Phone: Convergence of Data Service
Four Categories of Data Service,
>> Communication, Entertainment, Information, and Finance
32Nable Communications, Inc.
OMA Enabler Roadmap
33Nable Communications, Inc.
OMA Reference Model
Aggregation Proxy
SIP
/ IP
Cor
e
XDM
Clie
nt
ResourceList Server
PresenceServer
PresenceXDMS
Shar
ed X
DM
S
XDM-3
XDM-1
PRS-5
PRS-6
PRS-7
PRS-8
PRS-10
PRS-9 PRS-4
PRS-3
RLSXDMS
PRS-11
PRS-12
PresenceSource
PRS-1
PRS-2
Watcher
Rem
ote
Pres
ence
Net
wor
k (b
ased
on
SIP/
IP C
ore)
IP-1
DMCDMS
DM-1
XDM-2
XDM-4
Content Server
PRS-13
PRS-14
PRS-15
34Nable Communications, Inc.
IMS Client Overview
Application Part
IMS Client IMS Client
FrameworkFramework
Device Specific Part
IMS Client IMS Client can be layered into 3 main parts among which IMSCF(IMS Client Framework) is the mostimportant part to be an IMS-compliant client.
SW AV Codec
PTA (Push-to-All)
IMS enabled Game
Active Phone book VoIP
Video Conference
Instant Messenger
GSMA Video Sharing OMA PoC
Media Processing
RTP/RTCPSIP/SIMPLE
XCAP
MSRP
SigComp
SDP
DSP Chip
Windows Mobile 5.0
Qualcomm REX/DMSS
WIPI
Symbian
BREW
Digest AKA
35Nable Communications, Inc.
IMS Client Overview
• Technologies– Various Protocols Support
• SIP/SDP/RTP/RTCP/MSRP/XML/XCAP/…
– Various Standard Organizations• 3GPP, OMA, IETF,…
– Various Media Support• Voice, Video, Music, Images, etc.
• Wide range of Platform Support (Portability)– Any device– Key requirement for IMS client platform
• End-user applications– Attractive and Intuitive GUI– Easy to use
36Nable Communications, Inc.
IMS Client Framework
Memory, Network, File I/O, EventA/V Codec, Device
WiBro/Wi-Fi
SPIRIT,GIPS,Etc.
Platform Adaptation Layer
RTP/RTCP
SIP/SIMPLEw/ sigcomp MSRP XCAP
Media API IMS Core APITAPI etc.
CDMA/GSM
VideoSharing
VoIP/Conf
IM/Presence PoC
GenericSession
Mgt.
GenericEventMgt.
Other APIs
3rd
PtyEnablers
OtherDevices &Features
High Level APIs for IMS Applications
VCCClient
IMS Core Adaptation for Windows Window Mgt Local Data Mgt
Any Device and Platform (Qualcomm REX/DMSS, Windows Mobile, Symbian, etc.)
Video Telephony
InstantMessenger
InstantMessenger
VCC
VideoSharing
Application
3rd PtyAppls
3rd PtyAppls
IMS Framework
Windows OSAdaptation
(Option)
Applications
Platform & APIs
Nable IMS Client Architecture
3rd
PtyEnablers
MediaFilter
37Nable Communications, Inc. Contact : JunContact : Jun--Won Lee, Won Lee, [email protected]@nablecomm.com, +82, +82--1010--68246824--88258825
Top Related