3 GPP IMS IP Multimedia Subsystem Eric Wu
3 GPP: IMS (IP Multimedia Subsystem) Eric Wu 2012 National Central University Department of Computer Science and Information Engineering 1
Outline 3 GPP Evolution ¡ SIP Architecture ¡ Mobility Management ¡ SIP and 3 G Networks ¡ Department of Computer Science and Information Engineering 2
TDMA, CDMA, OFDMA Department of Computer Science and Information Engineering 3
HSPA+, LTE Possible Peak Downlink Rate Department of Computer Science and Information Engineering 4
MIMO Department of Computer Science and Information Engineering 5
Mobile Multicast/Broadcast TV Department of Computer Science and Information Engineering 6
3 GPP Releases cover the areas of: . Accesses (GSM, EDGE, HSPA, UMTS, LTE-Advanced, etc. ). Core Network (GSM Core, EPC). Services (IMS, MMTel) Department of Computer Science and Information Engineering 7
GPRS/EDGE Data Infrastructure Department of Computer Science and Information Engineering 8
Department of Computer Science and Information Engineering 9
UMTS Voice and Data Traffic Department of Computer Science and Information Engineering 10
Flat Architecture (Release 7 -> 8) Department of Computer Science and Information Engineering 11
EPC (Evolved-Packet Core) Department of Computer Science and Information Engineering 12
IMS-IP Multimedia Subsystem Department of Computer Science and Information Engineering 13
IMS: IP Multimedia Subsystem Department of Computer Science and Information Engineering 14
MMTel (Multimedia Telephony) Department of Computer Science and Information Engineering 15
Session Initiation Protocol (SIP) Department of Computer Science and Information Engineering 16
Session Initiation Protocol ¡ ¡ SIP is originally proposed by Columbia University and is specified by IETF. SIP is an end-to-end application-layer protocol l ¡ Establish, modify and terminate interactive multimedia sessions, e. g. , Vo. IP and video conference, between SIPbased users. Signaling protocol. Client-Server framework. H. 323 is a alternative signaling protocol to support Vo. IP. Department of Computer Science and Information Engineering 17
Microsoft Voice. NET Services Internet Telephony Service Provider (ITSP) Department of Computer Science and Information Engineering 18
Features of SIP ¡ Text-based l Easy implementation in Java or Perl ¡ l l ¡ Qo. S Transport-layer independence l ¡ Easy debugging Flexible and extensible Less signaling comparing to H. 323 l ¡ JSIP open source library UDP is commonly used. Forking a call request l l Call forwarding Parallel rings at different places Department of Computer Science and Information Engineering 19
H. 323 Department of Computer Science and Information Engineering 20
Introduction to SIP ¡ SIP Architecture ¡ Mobility management ¡ SIP and 3 G Networks ¡ Department of Computer Science and Information Engineering 21
Four SIP Logical Entities User agent ¡ Proxy Server ¡ Registrar ¡ Redirect Server ¡ Department of Computer Science and Information Engineering 22
User Agent User applications ¡ Both software and hardware ¡ Department of Computer Science and Information Engineering 23
Type of SIP Servers ¡ Proxy Server l ¡ Registrar l ¡ Application layer router used to relay SIP messages. Accept registration request from user agent. Redirect Server l Redirects caller to other servers. Typically, “SIP server” implements the functionality of Proxy, Registrar and Redirect Servers. Department of Computer Science and Information Engineering 24
SIP Addressing ¡ SIP give you a globally reachable address. l Email-like address. sip: leonard@a. ntu. edu. tw ¡ sip: 82828888@a. ntu. edu. tw ¡ User agents bind this address to Registrar by using SIP REGISTER message. ¡ Each user agent communicates with one another by using this address. ¡ Department of Computer Science and Information Engineering 25
SIP messages Request Line Department of Computer Science and Information Engineering Status Line 26
Example: SIP Registration Department of Computer Science and Information Engineering 27
Example: Session Establishment Department of Computer Science and Information Engineering 28
Routing Information Department of Computer Science and Information Engineering 29
Example: Session Forwarding Department of Computer Science and Information Engineering 30
Session Description Protocol (SDP) The message body of SIP ¡ SDP is used to describe a multimedia session ¡ Department of Computer Science and Information Engineering 31
RTP, RTCP, and RTSP ¡ Real Time Transport Protocol (RTP) l l ¡ Real Time Control Protocol (RTCP) l l ¡ Encode and decode media stream Recover the possible loss and jitter Qo. S feedback … Real Time Streaming Protocol (RTSP) l l l Control stored media VCR remote control Support play, record , pause, fast forward, and etc. Department of Computer Science and Information Engineering 32
RTSP protocol session Department of Computer Science and Information Engineering 33
SIP Interworking with the SS 7 Department of Computer Science and Information Engineering 34
Introduction to SIP ¡ SIP Architecture ¡ Mobility management ¡ SIP and 3 G Networks ¡ Department of Computer Science and Information Engineering 35
Wireless Technologies Convergence Department of Computer Science and Information Engineering 36
Mobility Management ¡ Mobility Classification l l Roaming Macro-mobility ¡ l Micro-mobility ¡ ¡ Domain mobility Subnet mobility Solutions l l Network layer solution: Mobile IP Application layer solution: SIP Department of Computer Science and Information Engineering 37
Mobile IPv 4: Registration Example Movement MH visits a foreign link Mobile IP kicks in Home address: 2. 0. 0. 3 Care-of-address: 1. 0. 2. 4 Internet Foreign Agent 2. 0. 0. 3 Home Agent Tunnel Foreign Link MH is at home Mobile IP is not used Home address: 2. 0. 0. 3 2. 0. 0 Home Link Foreign Agent Foreign Link Department of Computer Science and Information Engineering Correspondent Host 38
Mobile IPv 4: CH-to-MH Routing Example MH visits a foreign link Mobile IP kicks in Home address: 2. 0. 0. 3 Care-of-address: 1. 0. 2. 4 Internet Foreign Agent 2. 0. 0. 3 Home Agent Tunnel Foreign Link 2. 0. 0 Home Link Foreign Agent Foreign Link Department of Computer Science and Information Engineering Correspondent Host 39
Mobile IPv 4: MH-to-CH Routing Example MH visits a foreign link Mobile IP kicks in Home address: 2. 0. 0. 3 Care-of-address: 1. 0. 2. 4 Router Infrastructure Foreign Agent 2. 0. 0. 3 Home Agent Tunnel Foreign Link 2. 0. 0 Home Link Foreign Agent Foreign Link Department of Computer Science and Information Engineering Correspondent Host 40
Mobile IPv 4 Triangle route problem ¡ Micro-mobility improvement ¡ l l l Cellular IP, Campbell in Column University. Regional Registration, Perkins, Nokia Center. … Department of Computer Science and Information Engineering 41
Mobile IPv 6: Binding Update Department of Computer Science and Information Engineering 42
Application Layer Mobility Using SIP Terminal Mobility ¡ Session Mobility ¡ Department of Computer Science and Information Engineering 43
Terminal Mobility Department of Computer Science and Information Engineering 44
Terminal Mobility Department of Computer Science and Information Engineering 45
Session Mobility ¡ Allow a user to maintain a media session even while changing terminals. Department of Computer Science and Information Engineering 46
Comparison Department of Computer Science and Information Engineering 47
Introduction to SIP ¡ SIP Architecture ¡ Internetworking ¡ Mobility management ¡ SIP and 3 G Networks ¡ Department of Computer Science and Information Engineering 48
3 G UMTS Department of Computer Science and Information Engineering 49
Pure IP connectivity vs. Dedicated Multimedia subsystem Some mechanisms should be defined in 3 G to support multimedia session transfers? ¡ Market Perspective ¡ l l l Subscriber perspective Network operator perspective Third-party service provider perspective Department of Computer Science and Information Engineering 50
Subscriber Perspective ¡ Advantages l l ¡ It is free and flexible to choose applications. Reuse application in wired-networks Disadvantage l l l Trouble to choose the application and service provider. The demand of service package and one bill. Some application may lose Qo. S guarantee. Department of Computer Science and Information Engineering 51
Network Operator Perspective ¡ Advantages l ¡ Operators may not have experience in IP multimedia applications. They only focus in the IP connectivity. Disadvantages l l l Circuit-switch revenue will be decayed. Loss possible revenue for paving basic IP multimedia application, e. g. , Vo. IP. Issue of customer dissatisfaction for IP multimedia applications. Department of Computer Science and Information Engineering 52
Third-Party Service Provider Perspective ¡ Advantages l ¡ They don’t have to bother the peculiarity of wireless networks. They don not need extensive knowledge of wireless telecommunication networks and protocols. Disadvantages l They are unable to take advantage of the wireless network, e. g. , user location information. Department of Computer Science and Information Engineering 53
IP Multimedia Subsystem (IMS) Appear in Release 5 and beyond ¡ IMS comprises the network elements for control of multimedia sessions. ¡ Network operator provides both ¡ l l IP connectivity Multimedia session management Department of Computer Science and Information Engineering 54
Basic Add-in Features ¡ Call State Control Function (CSCF) l ¡ Provisioning of call control for IP multimedia applications. P-CSCF, I-CSCF, S-CSCF. Open Service Access (OSA) l Third-party are expected to stimulate innovative application, taking advantage of knowing the capabilities provided by wireless network providers. Department of Computer Science and Information Engineering 55
IP Multimedia Subsystem Media Resource Function Processor Media Resource Function Controller Enhanced HLR Perform internetworking related functions with PSTN Department of Computer Science and Information Engineering 56
Serving-CSCF Home Application Third-paty application Department of Computer Science and Information Engineering 57
S-CSCF Session control. ¡ Retrieve the information from HSS. ¡ Connect to Application Servers. ¡ Each user agent needs to attach a S-CSCF before setup a session. ¡ Analog to Registrar in SIP. ¡ Department of Computer Science and Information Engineering 58
Proxy-CSCF (P-CSCF) The first contact point within the IMS. ¡ Mobile node communicate with S-CSCF via PCSCF. Direct communication with S-CSCF is not allowed. ¡ l l l Integrity protection of SIP signaling. Compression due to sparse wireless resource (Sigcom). Inspect SIP signaling if the mobile node is in a visited network. Department of Computer Science and Information Engineering 59
Interrogating-CSCF (I-CSCF) Entry Point in a network operator. ¡ Hide the configurations, topology and capacity from outside. ¡ Analog to Proxy and redirect servers in SIP. ¡ Department of Computer Science and Information Engineering 60
Registration Department of Computer Science and Information Engineering 61
Session Setup Department of Computer Science and Information Engineering 62
MMTel and Circuit Switch internetworking Department of Computer Science and Information Engineering 63
Reference Mobile IP: SIP: IMS: Charles E. Perkins http: //people. nokia. net/~charliep http: //www. cs. columbia. edu/sip 3 GPP TS 23. 228 v 2. 0 http: //www. 3 gpp. org/ftp Department of Computer Science and Information Engineering 64
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