3GPP IM Call Model, Presence, and

Transcription

1 3GPP IM Call Model, Presence, and Push-to-talk t over Cellular l Chiang, Wei-Kuo ( 江為國 ) Assistant Professor Department of CSIE National Chung Cheng University Office : EA 311 Phone : ~ wkchiang@cs.ccu.edu.tw URL : ccu tw/~wkchiang/ wkchiang/ National Chung Cheng University Dept. Computer Science & Information Engineering

2 Next Generation Network Internet Telecom & Wireless Communication GPRS 3rd Parties App. Wireless CSCF CSCF App. Server SIP Server Internet WLAN MGCF MGW T-SGW MGW IP PSTN 2

3 Outline 3GPP IMS Call Model Application Triggering S-CSCF & AS Interactions Mobile Presence Presence Service 3GPP & OMA Presence Push-to-talk talk over Cellular PoC Architecture and Operations PoC High Level Procedures 3

4 IMS Service Architecture t Sh Application Servers HSS MAP Si Cx CAP CSE IM-SSF AS AS SCIM SIP AS SIP+ OSA AS OSA APIs OSA SCS SIP+ MRFC MEGACO MRFP ILCM OLCM RTP Voice Packets Incoming Leg Incoming Leg State Machine Ougoing Leg State Machine Outgoing Leg Registrar and Notifier Model Call Records Serving CSCF 4

5 Application Server Types SIP AS SIP-based Application Servers Examples Presence Server (3GPP TS ) IM-SSF PoC Server (3GPP TR ) IP Multimedia - Service Switching Function Host the CAMEL network features (3GPP TS ) OSA SCS Open Service Access Service Capability Server Use the OSA API (3GPP TR ) 5

6 Application Triggering i Application Server Service Logic HSS Service Platform Trigger Points SIP Interface ifc sfc SIP S - CSCF SIP S P T Filter Criteria SIP 6

7 Service Point Trigger Service Point Triggers (SPTs) SPTs are those points in the SIP signalling on which Filter Criteria can be set. The points may cause the S-CSCF to send/proxy the SIP message to an SIP AS/OSA SCS/IM-SSF SPTs are defined: SIP method (e.g. REGISTER, INVITE ) Presence or absence of some header field Content of some header field or Request-URI Direction of the request w.r.t. the served user Mobile Originated (MO) Mobile Terminated (MT) Registered/ i t Unregistered users 7

8 Filter Criteria i Filter Criteria (FC) A FC triggers one or more SPTs in order to send the related request to one specific app server. The set of Filter Criteria that is stored for a service profile of a specific user. ifc (initial Filter Criteria) - S-CSCF receives from HSS sfc (subsequent Filter Criteria) - S-CSCF receives from AS S-CSCF handles FCs in right sequence (by priority) FCs Contain the following information Address of Application Server Priority of Filter Criteria Trigger Point : composed by 1 to n SPTs Default handling Optional O l Service Information (e.g. IMSI) 8

9 S-CSCF for ifc ifc are stored in the HSS as part of the user profile and are downloaded to the S-CSCF upon user registration, or upon a terminating initial request for an unregistered user. S-CSCF on reception of a REGISTER request send a third-party REGISTER request to each AS that matches the Filter Criteria for the REGISTER event S-CSCF on reception of any other request 1)Set up filter criteria list by priority for that request 2)Parse the received request in order to find out the SPTs 3)Check with trigger points of unchecked highest priority FC If not match, S-CSCF proceed with step 4 If match, S-CSCF shall Add an indication to the request Forward the request to the AS. The AS then performs the service logic and may send the request back to the S-CSCF Proceed with step 4 if the request received again from AS 4)Repeat steps 2 and 3 until the last filter criteria 5)Route the request 9

10 Triggering i for REGISTER Download ifc From: UserA To: User A Call-ID: X 1. SIP REGISTER 3. SIP 200 OK From: UserA To: User A Call-ID: X HSS 2. Cx S-CSCF 4. Filter Checking From: S-CSCF To: User A Call-ID: Z Contact: S-CSCF 5.SIP REGISTER 6. SIP 200 OK 1. Inform about the user registration ti event 2. Trigger services Application Server Match a trigger 10

11 Triggering i for INVITE Sh HSS Sh AS 1 Cx AS 2 SIP Interface Service Logic SIP Interface Service Logic ISC 2 3 SIP message possibly 4.a with modification by AS1 ISC 5a SIP message possibly with modification by AS2 Incoming Call leg 1 S P I INVITE Match Initial Filter Criteria S-CSCF Filter Criteria X -> AS1 Filter Criteria Y -> AS2 Outgoing Call leg 6a 4b 4.b SIP message forwarded by S-CSCF SIP message forwarded by S-CSCF 11

12 Explanation (1/2) This example applies both for call originating and terminating procedure. But we assume this is a call originating procedure. User has registered with the network. Its filter criteria and addresses of the assigned application servers have been downloaded to its S-CSCF during registration via Cx interface. Also, the application server specific data may have been downloaded via the Sh interface to the application server during registration. In this example, two application servers are assigned to provide additional services to a subscriber and they are showed as AS1 & AS2. 12

13 Explanation (2/2) 1. User initiates a SIP session by sending INVITE to its S-CSCF. 2. On receiving this request, the S-CSCF evaluates the SPTs and checks if they match the initial filter criteria X for AS1. If they match, the S-CSCF forwards this request to AS1. 3. The AS1 performs any needed service logic based on the Service Key and sends the SIP request possibly with service related modification back to the S-CSCF. 4.a On receiving the request from the AS, the S-CSCF evaluates the SPTs and checks if they match the initial filter criteria Y for AS2. If they match the S- CSCF forwards the request to the associated Application Server AS2. 4.b If the request doesn't match any further filter criteria, the S-CSCF forwards this request to the next hop based on the route decision. 5.a The AS2 performs any needed service logic based on the Service Key and sends the SIP request possibly with service related modification back to the S-CSCF. 6.a The S-CSCF checks the request sent by AS2 and finds that no initial criteria is matched, then the S-CSCF forwards this request to next hop based on the route decision. 13

14 S-CSCF Functional Model HSS Cx Application Server ILCM Incoming Leg State Machine SIP+ OLCM Registrar and Notifier Model Ougoing Leg State Machine Serving CSCF Combined I/OLSM Incoming/Outgoing Leg State Model Store session state info Acting as a SIP Proxy, Redirect Server or User Agent dependant on the info received in the SIP request, the filter conditions specified or the state of the session ILCM and OLCM Incoming/Outgoing Leg Control Model Store transaction state info Registrar and Notifier handles registration & subscription to and notification of registration events 14

15 AS Functional Model Sh/Si HSS Cx Application Server Application Logic AS-ILCM SIP+ S-CSCF AS-OLCM AS-ILCM shall store transaction state may optionally store session state depending on the specific service being executed. interfaces to the S-CSCF (ILCM) for an incoming leg. AS-OLCM Similar to AS-ILCM Application Logic can access the HSS via the Sh 15 or Si interface to access subscriber related data

16 S-CSCF & AS Interactions ti S-CSCF acts as a SIP Proxy Application Server acts as Terminating User Agent (Voice Mail) or Redirect Server Call Forwarding - UE redirect Originating UA (Voice Mail Playback) SIP Proxy Call Forwarding - S-CSCF redirect 3 rd party call control AP as a B2BUA (invite MRFC) Play Announcements Multiparty Call Without AS From: X To: Y Call-ID: Z From: X To: Y Call-ID: Z SIP leg #1 SIP leg g #1 Application Server S-CSCF SIP leg #2 #1 From: PX To: QY Call-ID: R Z SIP leg #2 #1 From: P X To: Q Y Call-ID: R Z 16

17 S-CSCF & AS Interactions (1/5) S-CSCF acts as a SIP Proxy Application Server acts as Terminating User Agent (Voice Mail) or Redirect Server Call Forwarding - UE redirect Application Server From: X To: Y Call-ID: Z SIP leg #1 SIP leg #1 S-CSCF From: X To: Y Call-ID: Z 17

18 S-CSCF & AS Interactions (2/5) S-CSCF acts as a SIP Proxy Application Server acts as Terminating User Agent (Voice Mail) or Redirect Server Call Forwarding - UE redirect Originating UA (Voice Mail Playback) Application Server SIP leg #1 From: X To: Y Call-ID: Z S-CSCF SIP leg #1 From: X To: Y Call-ID: Z 18

19 S-CSCF & AS Interactions (3/5) S-CSCF acts as a SIP Proxy Application Server acts as Terminating User Agent (Voice Mail) or Redirect Server Call Forwarding - UE redirect Originating UA (Voice Mail Playback) SIP Proxy Call Forwarding - S-CSCF redirect From: X To: Y Call-ID: Z SIP leg #1 Application Server SIP leg #1 From: X To: Y Call-ID: Z SIP leg #1 From: X To: Y Call-ID: Z S-CSCF SIP leg #1 From: X To: Y Call-ID: Z 19

20 S-CSCF & AS Interactions (4/5) S-CSCF acts as a SIP Proxy Application Server acts as Terminating User Agent (Voice Mail) or Redirect Server Call Forwarding - UE redirect Originating UA (Voice Mail Playback) SIP Proxy Call Forwarding - S-CSCF redirect 3 rd party call control AP as a B2BUA (invite MRFC) Play Announcements for VM Multiparty Call for Conference From: X To: Y Call-ID: Z SIP leg #1 From: X To: Y Call-ID: Z SIP leg #1 Application Server S-CSCF SIP leg #2 From: P To: Q Call-ID: R SIP leg #2 From: P To: Q Call-ID: R 20

21 S-CSCF & AS Interactions (5/5) S-CSCF acts as a SIP Proxy Application Server acts as Terminating User Agent (Voice Mail) or Redirect Server Call Forwarding - UE redirect Originating UA (Voice Mail Playback) SIP Proxy Call Forwarding - S-CSCF redirect 3 rd party call control AP as a B2BUA (invite MRFC) Without AS Play Announcements Multiparty Call SIP leg #1 From: X To: Y Call-ID: Z Application Server S-CSCF SIP leg #1 From: X To: Y Call-ID: Z 21

22 Call Screening Originating Home Network Terminating Home Network HSS App. Server HSS App. Server I-CSCF S-CSCF 4 I-CSCF 7 S-CSCF Visited/Homeit Network 2 P-CSCF Visited/Home Network 9 P-CSCF 1 10 GGSN SGSN Radio Access Network Originating GGSN SGSN Radio Access Network Terminating 22

23 Call Forwarding (1/3) Network configuration Application Servers OSA AS OSA APIs OSA SCS SIP AS CSE CAP IM SSF S-CSCF based redirect UE redirect call flow ISC S-CSCF HSS Application Servers Application Servers S-CSCF HSS Home Network UE1 I-CSCF Home Network UE2 I-CSCF HSS Home Network UE3 UE3 S-CSCF UE1 23

24 Call Forwarding (2/3) UE redirect based call flows Terminating UE3 Home Network Terminating UE2 Home Network Originating UE1 Home Network Service S-CSCF HSS I-CSCF S-CSCF Platform 3. Locate UE2 2. INVITE. 1. INVITE UE1 4. Response 6. INVITE 5. INVITE Application performs number translation (based on CLI) Moved Temporarily 8. ACK Redirect Mode Moved Temporarily Moved Temporarily 12. ACK 11. ACK Moved Temporarily 14. ACK 16. INVITE 17. Bearer Establishment & Call Setup 15. INVITE 24

25 Call Forwarding (3/3) S-CSCF based redirect call flows Terminating UE3 Home Network Terminating UE2 Home Network Originating UE1 Home Network S-CSCF HSS I-CSCF Service S-CSCF HSS I-CSCF S-CSCF Platform 1INVITE 3. Locate UE22. INVITE 1. UE1 4. Response 6. INVITE 5. INVITE Application performs number translation (based on CLI) 7a. 181 Call Is Being Forwarded 7b. 181 Call Is Being Forwarded Proxy Mode 7c. 181 Call Is Being Forwarded 8 INVITE 7d. 181 Call Is Being Forwarded 10. Locate UE3 9. INVITE 11. S-CSCF UE3 UE3 12a. INVITE 12b. INVITE No AS involvement 13a. 183 Session Progress) 13b. 183 Session Progress 13c. 183 Session Progress 13d. 183 Session Progress 13e. 183 Session Progress 13f. 183 Session Progress 13g. 183 Session Progress 13h. 183 Session Progress 14. Bearer Establishment & Call Setup 25

26 Voic il Recording (1/3) Originating Home Network Terminating Home Network HSS App. Server HSS App. Server I-CSCF S-CSCF 3 I-CSCF 6 S-CSCF Visited/Homeit Network 2 P-CSCF Visited/Home Network P-CSCF 1 GGSN SGSN Radio Access Network Originating GGSN SGSN Radio Access Network Terminating 26

27 Voic il Recording (2/3) The HSS responds back to I-CSCF with an indication that I-CSCF should select S-CSCF for this MT call to the unregistered Public User Identity of the user or provide the I-CSCF with the previously allocated S-CSCF name. Terminating Network I-CSCF HSS S-CSCF 1. INVITE 2. Cx-Loc Query 3. Cx-Loc Query Resp. 4. S-CSCF Selection 5. INVITE Cx-Put/Cx-Pull 7. Cx-Put/Cx-Pull-Resp. 8. Service Control 9. S-CSCF performs further actions

28 Voic il Recording (3/3) AS (acting as a terminating UA) AS (Voic Server) S- CSCF AS (Voic Server) S- CSCF Voic Application 18. Voic Server Plays Annoncement 19. Caller Leaves Message 9. QOS Establishment / Resource Reservation 28

29 Voic il Replaying (1/2) Home Network Third Party Registration HSS App. Server 3,5 4,6 8,9 10,11 12 I-CSCF 7 S-CSCF Visited Network P-CSCF 2 2 P-SCSF 1 1 GGSN SGSN Radio Access Network GGSN SGSN Radio Access Network 29

30 Voic il Replaying (2/2) AS (Voic Server) S- CSCF 16. UPDATE Unauthorized OK Ringing 30. User retrieves voic il messages 15. QoS Establishment / Resource Reservation 30

31 Multimedia li Resource Function MRFC (Multimedia Resource Function Controller) Control media stream resources in the MRFP Interpret information from AS & S-CSCF, and control MRFP accordingly MRFP (Multimedia Resource Function Processor) Bearer control on Gi interface Mixing of media streams AS Media stream processing Application Server~S-CSCF~MRFC Announcement Conferencing Transcoding ISC S-CSCF Mr MRFC Mp MRFP Gi 31

32 Announcement (/ (1/2) AS (acting as B2BUA) 3PCC with MRFC Home Network for calling party AS S-CSCF MRFC 32

33 Announcement (2/2) PRACK Provisional ack. Allows preconditions and other advanced call setup features UPDATE Allows modification of session without full re-invite cycle 33

34 Ad Hoc Conference (1/2) AS (acting as B2BUA) 3PCC with MRFC Sessions exist between UE-1 and UE-2 2, and between UE-1 and UE-3. Request is to put all parties together for an Ad-hoc conference (multi-party call). 100 Trying is sent after each INVITE, but it isn't shown AS 1. INVITE (MPTY)[1] (Trying) 4. Service Logic Home Network for calling party 3. INVITE (MPTY)[1] 5. INVITE (UE-2 SDP)[2] S-CSCF 6. INVITE (UE-2 SDP)[2] MRFC OK (UE-2 2SDP)[2] 9. INVITE (UE-2 SDP)[3] OK (UE-2 2SDP)[3] 14. ACK (UE-2 SDP) [2] 16. ACK (UE-2 SDP) [3] 18. INVITE (UE-3 SDP)[4] OK (UE-2 2SDP)[2] 10. INVITE (UE-2 SDP)[3] OK (UE-2 2SDP)[3] 15. ACK [2] 17. ACK [3] 19. INVITE (UE-3 SDP)[4] 11. Establish path between UE-2 and MRFP OK (UE-3 SDP)[4] OK (UE-3 SDP)[4] 34

35 Ad Hoc Conference (2/2) Home Network for calling party AS S-CSCF MRFC 22. INVITE (UE-3 SDP)[5] 23. INVITE (UE-3 SDP)[5] OK (UE-3 SDP)[5] 27. ACK (UE-3 SDP) [4] 29. ACK [5] 31. INVITE (UE-1 SDP)[6] OK (UE-1 SDP)[6] OK (UE-1 SDP) [1] OK (UE-1 SDP) [1] OK (UE-3 SDP)[5] 28. ACK [4] 30. ACK [5] 32. INVITE (UE-1 SDP)[6] OK (UE-1 SDP)[6] 24. Establish path between UE-3 and MRFP 37. Establish path between UE-1 and MRFP 38. ACK [6] 39. ACK [6] 40. ACK [1] 41. ACK [1] 35

36 Reference for IM Call Model 3GPP TS V6.3.0 ( ) 03) IP Multimedia (IM) Session Handling; IM Call Model; Stage 2(Release 6) The Intelligent Network : Customizing Telecommunication Networks and Services 1998 by Uyless Black Prentice-Hall PTR Next Generation Intelligent t Networks 2002 by Johan Zuidweg Artech House 36

37 Summary 3GPP IM Call Model Next Generation Intelligent Network will use SIP-based Application/Service Triggering 37

38 Outline 3GPP IMS Call Model Application Triggering S-CSCF & AS Interactions Mobile Presence Presence Service 3GPP & OMA Presence Push-to-talk talk over Cellular PoC Architecture and Operations PoC High Level Procedures 38

39 Presence Service The presence service (PS) results in presence information of a user and information on a user's devices, services and services components being managed by the wireless network. Together, user, these devices, services and services components are termed presentity (presence entity) The presence service provides access to presence information to be made available to other users or services. The types of services that could be supported by the presence service New communications services -"chat", instant messaging, Information services - advanced push services Enhanced existing services 39

40 Presence Information Presence Information Usage information (Online/Offline/etc) Availability information (Busy/Away/On lunch/etc) Location information (At work/at home/etc) Location information (Positioning/etc) Device information (PC/PDA/Mobile phone/etc) Network information & capabilities (WLAN/GPRS) Preferred medium: text, , voice, video, Preferences (caller and callee preferences) Presence Notifications about a person s availability and status sent directly to the recipient (not stored) 40

41 Presentity Presentity presence info My name is Mark and I am supported by the presence service. I have a presentity which represents me, and I am the principal of my presentity. As the principal, I supply information to my presentity. user status p p p y location info set of access rules Available Discreet Not available My presentity consists of information Invisible (describing my ability City and willingness to communicate) and Country access rules (describing how my presence information may be accessed). User Status Location Mark s Presentity Access Rules 41

42 Application of Access Rules I think the car alarm is playing up Hello, weather is great here! see you in the bar at 7:30 Paggy Mark Paul Available Discreet User Status Access Rules Not available Invisible City Location Jude shame, Mark can t tell me where Paul is Country Mark s Presentity looks like Mark is not around! Watcher group 42

43 Presence Operation Modes Peer-to-Peer Subscribe Watcher Presentity Notify Client-to-Server Subscribe Presence Server Publish Notify Watcher Presentity + Network Info Presence Network Agent HSS, HLR, VLR, IMS CSCF SGSN, GGSN MSC, AAA Server Register, Invite (call state) 43

44 3GPP PS Architecture t Presence suppliers Watcher applications Presence External agent (Presence information provided by elements outside the provider s network) Pex Pw Watcher Presence Proxy Presence User agent (Presence information provided by the user) Peu Pw Presentity Presence Proxy Px Presence Network agent (Presence information provided by the network) Pen Pw HSS (HLR) Pr 3GPP AAA Server Pp PDG Ph Pi Pc Pg Pk Pl Presence server (home network) HSS/HLR S-CSCF MSC Server /VLR SGSN GGSN GMLC Interfaces Ph, Pi, Pc, Pg, Pk and Pl are based on existing Release 5 procedures e.g. CAMEL, MAP, CAP, RADIUS, ISC, Cx, Sh. The Pr, Pp interfaces are based on existing Release 6 procedures of the 3GPP-WLAN interworking architecture. 3GPP TS

45 PS Functional Entities Presence Server (PS) The Presence Server shall reside in the presentity's home network. Presence User Agent (PUA) The Presence User Agent shall send the Presence information to the Presence Server. Presence Network Agent (PNA) The Presence Network Agent shall receive Presence information from network elements The Presence Network Agent shall be able to send requests to the HSS/HLR The Presence Network Agent shall publish the Presence information to the Presence Server 45

46 Presence Proxies Watcher application Pw = Gm P-CSCF S-CSCF ISC Pw = ISC Application Server (Presence List) Watcher Presence Proxy Pw =Mw Watcher application I-CSCF HSS Px = Cx S-CSCF Pw = ISC Presence Server Presentity Presence Proxy 46

47 3GPP Presence Architecture t UE1 Home Network Application Server Pw ( ISC ) Watcher Application UE2 Home Network Presence Pen Network Agent Ph (MAP) Pi ( ISC ) Network Controlled Info (Location Info/Connectivity State) HSS Cx SIP Presence Server Subscriber Controlled Info (User Availability & Preference) Pw ( ISC ) S-CSCF 1 SIP I-CSCF 2 S-CSCF 2 Watcher Presence Proxy P-CSCF 1 SIP UE 1 Watcher Presentity Presence Proxy Presence User Agent P-CSCF 2 SIP UE 2 Presentity 47

48 IMS Watcher Registering i Home Network of watcher Home Network of presentity UE Watcher Presence Proxy P-CSCF S-CSCF Presentity Presence Proxy I-CSCF S-CSCF HSS Presence Server 1.SubscribePres 2.SubscribePres 3.SubscribePres 4. Query 5.Resp 6.SubscribePres 7.SubscribePres 12.MsgSck 11.MsgAck 14.NotifyPresUp 15.NotifyPresUp 16.MsgAck 17.MsgAck 10.MsgAck 18.MsgAck 9.MsgAck 8.MsgAck 13.NotifyPresUp The PS sends the NOTIFY straight to the originating watcher presence proxy, by-passing the presentity presence proxy. 48

49 Updating Presence Home Network of Presentity UE P-CSCF S-CSCF Presence Server 1. PressUpdateMsg 2. PressUpdateMsg 3. PressUpdateMsg 6. MsgAck 5.MsgAck 4.MsgAck 49

50 Notifying i IMS Watcher Home Network of Presentity Home Network of Watcher Presence Server Presentity Presence Proxy Watcher Presence Proxy S-CSCF I-CSCF S-CSCF P-CSCF UE 1. NotifyPresUp Presence Server has updates presence information to send to watcher as a result of user or user agent updates The PS sends the NOTIFY straight to the originating watcher presence proxy, by-passing the presentity presence proxy. 6. MsgAck 2. NotifyPresUp 5. MsgAck 3. NotifyPresUp 4. MsgAck 50

51 Subscribing to Watcher List subscription to the Presence Server requesting notification of any new watcher subscriptions Presence Presence User Agent Server 1. SubscribePresence (Watcher List) Presentity Presence Proxy Watcher Presence Proxy 2.MsgAcks 5.Watcher Request Notification 4. SubscribePres 3. SubscribePres 8. Update SubscriptionAuthorisationPolicies 6. MsgAck inform the watcher that PS has received the watcher s request. 9. NotifyPresUp 7. MsgAck If the UpdateSubscriptionAuthorisationPolicies indicates that the subscription is blocked then steps 9 and 10 are not performed. 10. NotifyPresUp 51

52 OMA PS Architecture t GLMS Management/Administration GM -4 GLM Cli ent Pres sence User Agent ACCESS NE ETWORK GM -3 GLMS GM -2 SIP / IP Co ore PRS-1 PRS -2 PRS -3 PRS -4 GM -5 Presence Server Presence Network Agent Presence External Agent Network P Core) e Presence N d on a SIP/IP Remote (based UE 52 IP-1

53 Presence server The Presence Server (PS) SHALL provide : Receive and manage presence information Provide Subscription Authorization Policy Provide a watcher, if required, configurable filtering function that is used to limit the information that t is delivered d to a watcher Allow watchers to request and subscribe to the full set of presence info of a presentity Generates partial notifications to a watcher Verifies the identity of the watcher that subscribes to presentity's s presence info Supports SIP-based communications with the Presentity SIP/IP Core 53

54 Presence User Agent The Presence User Agent (PUA) collects presence info associated with a presentity representing a principal Assemble the presence info in the standard d format Send the presence information to the PS Manage the Subscription Authorisation ti Policy Identify itself uniquely among other PUAs of the same presentity when publishing presence information Handle any necessary interworking required to support terminals that do not support the standard interface The PUA may be located in the user s terminal or within a network entity 54

55 Presence Network Agent The Presence Network Agent (PNA) SHALL collect the presence information from the various network elements and send it to the PS. The PNA MAY also notify the PS when a PUA is disconnected. This can be achieved by using keep-alives (heartbeat) mechanism from the PUA to the PNA. MSC Server/ VLR GGSN MSC/MSCe Presence Network Agent 3GPP Presence Network Agent 3GPP2 HSS/HLR S-CSCF SGSN GMLC HSS/HLR AAA/HA/ Position S-CSCF PDSN Server 55

56 SIP/IP Core Routes the SIP signaling between PUA and PS Provides discovery & address resolution services Supports SIP compression Performs authentication and authorization of the PUA based on user s service profile Maintains the registration state Provides charging information OMA SIP/IP Core = 3GPP Presence Proxies 56

57 GLMS Group and List Management Server (GLMS ) Provides list management operations to create, modify, retrieve and delete groups and lists Provides storage for groups and lists 57

58 PS General Architecture t Presence Server S-CSCF 1 SIP/IP Core SIP/IP Core I-CSCF 2 Watcher Presentity S-CSCF 2 P-CSCF 1 P-CSCF 2 UE 1 Watcher Watcher Presentity Presence User Agent UE 2 Presentity 58

59 Publishing Presence Info Home Network Presentity PUA SIP/IP Core PS 1. PUBLISH 2. PUBLISH 3200OK OK 59

60 Sending a Subscribe Request Home Network of watcher Home Network ofpresentity Watcher PUA Watcher SIP/IP Core Presentity SIP/IP Core Presence PS 1. SUBSCRIBE 2. SUBSCRIBE 3. SUBSCRIBE OK OK OK 7. NOTIFY 8. NOTIFY OK OK 60

61 Receiving i a Notification Home Network of Presentity Home Network of Watcher Presence Server has updates to send to the watcher Presence Server PS Presentity SIP/IP Core 1NOTIFY 1. Watcher SIP/IP Core 2. NOTIFY Watcher OK 4200OK 4. 61

62 Partial Notifications Home Network of Presentity Watcher SIP/IP Core PS PUA 1. SUBSCRIBE 2. SUBSCRIBE OK OK 5. NOTIFY 6. NOTIFY OK full state presence document OK 9. PUBLISH OK 12. NOTIFY OK 11. NOTIFY a partial presence document formulated showing only the changed tuple OK 62

63 Subscribe Presence H om e N H e om t w o e r k N e o tf w o a r t k c h o er f w a t c h er H om e N e t w o r k o f presentity W atc PUA he r W a tc h e r S IP /IP C ore P re s e n tity S IP /IP C o re Presence Serv er 1. SUBSCRIBE 2. SUBSCRIBEs 3. SU BSCRIBEs OK 4 A uth orizat ion O K O K 9. N O TIFY 8. N O TIFY O K OK 12. N O TIFY 1 3. N O T IF Y O K OK The PS sends the NOTIFY straight to the originating watcher SIP/IP core, by-passing the presentity SIP/IP core. Presence Server has updates to send to the watcher 63

64 Blocking Home Network of presentity W atcher SIP/IP Core Presence PS Server 1. SUBSCRIBE 2. SUBSCRIBE Forbidden or 603 Decline Forbidden or 603 Decline 64

65 Polite Blocking Home Network of presentity Watcher SIP/IP Core PS 1. SUBSCRIBE 2. SUBSCRIBE OK OK 6. NOTIFY OK 5. NOTIFY After applying the subscription authorization policies of the presentity, the PS determines to reject the subscription request OK 65

66 Watcher Initiated t Canceling Home Network of presentity Watcher SIP/IP Core PS 1. SUBSCRIBE Expires header field set to 0 2. SUBSCRIBE OK OK 5. NOTIFY 6. NOTIFY OK Subscription-State St t header field set to terminated OK 66

67 PS Initiated t Canceling Home Network of presentity Watcher SIP/IP Core PS 1. NOTIFY 2. NOTIFY OK Subscription-State header field set to terminated OK 67

68 Subscribing Watcher Info Home Network of Presentity Watcher SIP/IP Core After some time a Watcher attempts to subscribe to the PUA s Presence info by sending a SUBSCRIBE message SUBSCRIBE Accepted 10. NOTIFY OK SUBSCRIBE Accepted 9. NOTIFY OK PS 1. SUBSCRIBE OK 3. NOTIFY OK PUA NOTIFY with Subscription-State" of "pending" value, which indicates that the subscription has been received, but that policy info is insufficient to accept/ deny the Subscription at this time. 13. NOTIFY 16. NOTIFY OK 17. NOTIFY OK OK authorizes the subscription 11.Subscription 15.Subscription Authorisation Notify the change in status of subscription (changes from pending to active) 20. NOTIFY OK

69 Aggregating Presence Info Aggregating Published Presence information Home Network from multiple of sources Presentity PUA1 PUA2 Watcher SIP/IP Core PS 1. PUBLISH 2. PUBLISH OK OK 5. PUBLISH 6. PUBLISH OK OK 10. NOTIFY OK 9. NOTIFY OK 69

70 References for Presence (1/2) 3GPP TS V6.2.1 ( ) Presence Service; Stage 1(Release 6) 3GPP TS V6.6.0 ( ) Presence Service; Architecture & functional description (Release 6) Stage 2 - Presence using SIMPLE Draft Version August 2004 OMA-PAG-SIMPLE-AD-V1_1_ D Push-to-talk over Cellular (PoC) - Presence Service; PoC Release 2.0 Presence Service V2.0.9 ( ) Comneon, Ericsson, Motorola, Nokia, Siemens 70

71 References for Presence (2/2) CCL Technical Journal 3GPP Mobile Presence: September 2003 OMA-Open Mobile Alliance/Wireless Village Jabber Software Foundation,The Jabber Protocol / IETF IMPP (Instant Messaging and Presence Protocol) IETF SIMPLE (SIP for Instant Messaging and Presence Leveraging Extensions) IETF XMPP (Extensible Messaging and Presence Protocol) 71

72 Summary 3GPP/OMA Mobile Presence Service Maybe to be a Killer Service Platform Integration of other VAS (PoC, LBS, MMS) 72

73 Outline 3GPP IMS Call Model Application Triggering S-CSCF & AS Interactions Mobile Presence Presence Service 3GPP & OMA Presence Push-to-talk talk over Cellular PoC Architecture and Operations PoC High Level Procedures 73

74 Push-to-talk t Service Push-to-talk Service 74

75 What is Push-to-talk t? Mobile phone user can only push one button to talk with another person or a group. push to talk provides end-users with the ability to quickly find one another and engage in brief, burst-oriented style communication. Advances in market adoption and technology evolution of voice over wireless IP will enable improvements in Push-to-Talk (PTT). 75

76 Introduction ti to PoC Originally introduced in the US by Nextel through its partnership with Motorola and its use of the iden technology Combining aspects of cellular mobile communications, presence detection, and walkie-talkie style communications, Ei Ericsson, Siemens, Motorola and Nokia published the Push-to-talk over Cellular (PoC) release 1.0 at Aug OMA form the PoC (Push-to-talk over Cellular) working group at Nov

77 PoC Market PoC suited for demands d for quick comm. among users. PoC is provided in half-duplex mode transmission occurs in both directions, but not at the same time each must wait to speak the inability to interrupt lends to quick exchanges of info. The PoC market will continue to evolve & ultimately represent service opportunities for the more traditional markets (dispatch and mobile workforce users) as well as more mass market users such as the youth market. PoC will become important for government, public safety personnel and other officials i as a communications tool, serving the need for efficient communications during times of emergency, disaster, or threats. 77

78 PoC Technology Support At the core of PoC is an IETP standardized protocol known as SIP used for IP Telecom and 3GPP IP Multimedia Subsystem infrastructure. Being that it uses IP as a transport/bearer, PoC is highly dependent on the roll-out, out expansion and improvements of 2.5G and 3G technology and infrastructure. The Open Mobile Alliance (OMA) is working to standardize Push-to-Talk over Cellular (PoC) (below). 78

79 Goals of OMA PoC WG Develop specifications to permit deployment of interoperable PoC services Develop a common PoC service framework that could be deployed over a variety of networks The application framework will be modeled d over the capabilities of 3GPP IMS & 3GPP2 MMD PoC SHALL utilize SIP/IP Core in 3GPP and 3GPP2 Any non-ims based SIP network is assumed to have the same functionality as IMS The initial iti focus develop an open standard to enable adoption of PoC service over mobile networks 79

80 PoC Standardization di ti (1/2) OMA is standardizing Push-to-Talk over Cellular (PoC) infrastructure & processes evolution of PTT from proprietary approaches to a more open approach ultimately enable inter-carrier PoC OMA - offer infrastructure network elements: PoC Server: Contains the PoC server-side logic providing functions: end-point for SIP signaling and voice bursts, handles participant lists distribution, reporting p g to the charging g system, and media distribution. 80

81 PoC Standardization di ti (2/2) Group/List Manager Server (GLMS): Responsible for management of contact lists, group lists, access lists, and permissions management IMS Core: Contains SIP proxies and SIP registers. The UE access the IMS Core for purposes of SIP signaling to the PoC Server. The IMS Core also handles HSS/AAA functions and triggering of personal & group instant talk sessions. User Equipment (UE): Terminal equipment containing the PoC app. software OMA - standardize the processes: roaming, identification, addressing, and modes of operation (session establishment and answering) 81

82 OMA PoC Architecture t GLMS Management/Administration It: Floor Control and media Itn: Floor Control and media Is: PoC Client to Proxies Session Signaling (SIP) If: Proxy to PoC Server Session Signaling (SIP) Ips: SIP/IP Core to PoC Server (SIP) In: Proxy to Proxy Session Signaling (SIP) Im: Group Mgmt to PoC Client (XCAP) XCAP XML Configuration Access Protocol Ik: Group Mgmt to PoC Server PoC client RK ACC CESS NETWO Im Is It IMS/MMD cap pabilities) SIP / IP Co ore (based on Igs Ik If Ie GLMS Ips PoC Server In Ipl Presence Server Itn Network Remote PoC 82

83 OMA PoC Key Entities PoC Specific Entities PoC Client PoC Server Group and List Management Server (GLMS) External Entities SIP/IP Core Presence Server 83

84 OMA PoC Client PoC Client A software resides on the mobile terminal and is used to access PoC service Perform Registration with SIP/IP core Participate in authentication with SIP/IP core Provide access to different lists in GLMS, e.g., contact lists, group lists etc. Provide the capabilities for PoC session initiation, participation and termination Support floor control procedures (e.g., make request and respond to commands) Incorporate configuration data downloaded by the PoC Application Service Infrastructure Provide access to presence information 84

85 OMA PoC Server (1/4) PoC Server Provides PoC session handling Provides SIP session handling, such as SIP session origination, termination, etc. Provides the Media distribution Provides the floor control functionality including talker identification Provides policy enforcement for participation in group sessions Provides policy handling for incoming PoC session (e.g. access control, availability status, etc) Provides the participants info (i.e. user nicknames) Collects and provides media quality information Collects and provides the charging information 85

86 OMA PoC Server (2/4) PoC Server The PoC server MAY perform a Controlling PoC Function or Participating PoC Function. A PoC server MAY perform both a Controlling PoC function and a Participating PoC function at the same time. The determination of the PoC Server role In case of 1-11 PoC Session & Ad-hoc PoC group session the PoC server of the inviting user shall perform the Controlling PoC Function. In case of Chat PoC group & pre-arranged group session the PoC server owning/hosting the group identity shall perform the Controlling PoC Function. 86

87 OMA PoC Server (3/4) 1-1 PoC Session in a multiple network environment Network A Controlling POC Function 1:1 Participating POC Function A 1:1 POC Client A 1:1 Participating POC Function B 1:1 POC Client B Network B 87

88 OMA PoC Server (4/4) PoC Group session in a multiple network environment Network X Network A Controlling POC Function 1:N Participating POC Function A 1:1 POC Client A Network B Participating POC 1:M Function B 1:1 POC Client B 88

89 GLMS & PS Group and List Management Server (GLMS) PoC users use the GLMS to manage groups and lists (e.g. contact and access lists) that are needed for the PoC service. Provides list management operations to create, modify, retrieve and delete groups and lists Provides storage for groups and lists Presence Server (PS) Provides availability information in support of the PoC Service 89

90 SIP/IP Core PoC SHALL utilize SIP/IP Core based on capab. from IMS as specified in 3GPP & 3GPP2 SIP/IP Core in support of the PoC Service Routes SIP signaling between PoC Client & PoC Server Provides discovery and address resolution services Supports SIP compression Performs authentication & authorization of PoC Client based on user s service profile Maintains i the registration i state and the SIP session state Provides charging information 90

91 PoC Identification PoC address Each user SHALL have one or more PoC Addresses, known as public user identity in format of SIP URI[RFC3261] or TEL URI[RFC2806bis] At least one PoC Address SHALL be in the format of a SIP URI. SIP/IP Core will translate a TEL URI to a SIP URI for routing. Examples of PoC Addresses sip:joe.doe@operator.net tel: Private user identity assigned by network operator for authentication username@realm Group identities A group is identified with a group identity. Generated and stored in the GLMS 91

92 Talk Burst Arbitration ti (1/4) The PoC Server SHALL arbitrate talk bursts SHOULD confirm the request to send a talk burst if no other PoC Client has the permission SHALL reject the request to send a talk burst if another PoC Client has the permission and the PoC Server or the PoC Client does not support queuing. talk burst queue SHALL place a request according to the priority SHOULD support # queue positions per session at least equal to # participants up to the permitted maximum # participants SHALL be at most one request queued for each PoC Client SHALL revoke the permission to talk if the length exceeds a configurable maximum talk burst duration 92

93 Talk Burst Arbitration ti (2/4) The PoC Client and the PoC Server SHALL support Talk Burst request (Client->Server) Talk Burst Confirm response (Server->Client) Talk Burst Reject response (Server->Client) Talk Burst Completed indication (Client->Server) No Talk Burst indication (Server->Client) Receiving Talk Burst indication (Server->Client) Stop Talk Burst indication (Server->Client) Floor Control (RTCP - IETF RFC 1889) request, grant, deny, release, idle, taken, revoke (RTCP APP) quality feedback (RTCP SR & RR), RTCP BYE 93

94 Talk Burst Arbitration ti (3/4) Talk burst control 7 floor control messages Floor Request A UE requests that the Controlling PoC server shall allocate the media resource to his device Floor Grant The Controlling PoC server notifies the UE that it has been granted the floor Floor Deny The Controlling PoC server notifies a UE that it has been denied permission to use the media resource Floor Release A UE notifies the Controlling PoC server that it is releasing the media source Floor Idle The Controlling PoC server notifies the UEs that no one owns the media source Floor Taken The Controlling PoC server notifies all UEs (except the granted UE) that the floor has been granted to another UE Floor Revoke Allows the Controlling PoC server to revoke the media resource form a UE 94

95 Talk Burst Arbitration ti (4/4) If the PoC Server and the PoC Client support queuing of the Talk Burst Request Talk Burst Request Queued response Server -> Client Talk Burst Queue (client) Position request Client -> Server Talk Burst Queue Position response Server -> Client Talk Burst Queue (others) Identity request Client -> Server Talk Burst Queue Identity response Server -> Client 95

96 PoC Session Set-Up (1/2) On-Demand Session The On Demand session provides a mechanism to negotiate media parameters such as IP address, ports and codecs, which are used for sending the media and floor control packets between the PoC Client and the home PoC Server when the user wants to actually establish a PoC session. This mechanism allows the PoC Client to invite, via PoC server(s), other PoC clients or receive PoC sessions by using the full session establishment procedure each time the user wants to establish/receive/join i /j i a PoC session. Media parameters may be negotiated again in this mechanism. 96

97 PoC user (UE-A) 1.Power On PS Domain PoC AS & PS Domain PoC user (A) IMS Core (B) (UE-B) 1.Power On 2. PS Attach 2. PS Attach 3. Establish PDP context 3. Establish PDP context 4. Perform IMS Registration 5 Initiate PoC Session 4. Perform IMS Registration 6a. Establish PDP context for media 6b. INVITE 7. INVITE 8a. 200 OK 8b. Modify PDP context for media 9a. Establish PDP context for media 9b. 200 OK 10.Floor Control 11.Transfer of Media

98 PoC Session Set-Up (2/2) Pre-established Session The pre-established session provides a mechanism to negotiate media parameters such as IP address, ports and codecs, which are used for sending the media and floor control packets between the PoC Client and the home PoC Server before establishing the PoC session. This mechanism allows the PoC Client to invite other PoC clients or receive PoC sessions without negotiating again the media parameters. After the pre-established session has been set up (once the PoC user has registered), the PoC Client is able to activate media bearer whenever needed. 98

99 PoC user PS Domain PoC AS & PS Domain PoC user (UE-A) (A) IMS Core (B) (UE-B) 1.Power On 1.Power On 2. PS Attach 2. PS Attach 3. Establish PDP context t 3. Establish PDP context 4. Perform IMS Registration 5. Set up of Pre-established established session 5a. INVITE 5b. 200 OK 4. Perform IMS Registration 5. Set up of Pre-established session 7 6. Establish PDP context for media 6. Establish PDP context for media Initiate PoC Session 8. Establish media (e.g. REFER) 10. ACCEPT 9. Floor control: Floor status 11. Floor Control establishment 12.Transfer of Media

100 Ad-hoc PoC Architecture t PoC Server Controlling PoC Server Participating PoC Server PoC Server Participating Participating S-CSCF 1 SIP/IP Core I-CSCF 2 SIP/IP Core SIP/IP Core S-CSCF 2 P-CSCF 1 P-CSCF 2 UE 1 Watcher PoC Client Inviting PoC PoC Subscriber Subscriber Presence User Agent UE 2 Presentity 100

101 Ad-hoc PoC Group Session (/8) (1/8) In the Ad-hoc PoC group session setup one PoC subscriber selects several other PoC subscribers to be invited to an ad-hoc PoC group session PoC session setup is similar case with ad-hoc PoC group session except only one PoC subscriber is invited by the inviting PoC subscriber. Setup On-demand session (Un-/Confirmed indication) Pre-established session (Un-/Confirmed) 101

102 Ad-hoc PoC Group Session (2/8) From PoC Client On-demand Session Confirmed indication PoCClient A Home Network & Controlling Network PoC client A 1. INVITE SIP/IP Core A PoC server A (participating & controlling) 2. INVITE Invitations to the invited PoC subscriber Optional 4. RINGING 3. RINGING First Ringing response Sends SUBSCRIBE request in order to receive information about the result of the invitations. When final response is received from an invited PoC subscriber, 5. SUBSCRIBE (result) 8. OK 12. NOTIFY (result) 9. Floor Granted 10. Media 6. SUBSCRIBE (result) 7. OK First accepted invitation If none of the invited PoC subscribers accepts the invitation, the PoC server A (participating & controlling) rejects 11. NOTIFY (result) the PoC session Response for the invitation 102

103 Ad-hoc PoC Group Session (3/8) To PoC Client PoCclient A Home Network & Controlling Network PoCClient B Home Netw ork On-demand Manual answer SIP/IP Core A PoC server A (participating & controlling) PoC server B (participating) SIP/IP Core B PoC client B 1. INVITE 2. INVITE 3. INVITE 4. INVITE 5. INVITE 7. RINGING 6. RINGING 8. RINGING 9. RINGING 10. RINGING 12. OK 13. Ok 11. OK 14. OK 15. OK 16. Floor Status 17. Floor Status 103

104 Ad-hoc PoC Group Session (4/8) From PoC Client PoC On-demand Session PoC client A Unconfirmed indication Client A Home Network & Controlling Network 1. INVITE SIP/IP Core A PoC server A (participating & controlling) 2. INVITE Invitations to the invited PoC subscriber Sends SUBSCRIBE request in order to receive information about the result of the invitations. Optional 4. UNCONFIRMED OK 5. Floor Granted 6. Media 7. SUBSCRIBE (result) 3. UNCONFIRMED OK 8. SUBSCRIBE (result) First AUTO-ANSWER response b t th lt f th i it ti 9. NOTIFY (result) Response for invitation 10. NOTIFY (result) When final response is received from an invited PoC subscriber, 104

105 Ad-hoc PoC Group Session (5/8) To PoC Client PoCclient A Home Network & Controlling Network PoCClient B Home Netw ork On-demand Automatic answer SIP/IP Core A PoC server A (participating & controlling) PoC server B (participating) SIP/IP Core B PoC client B 1. INVITE 2. INVITE 3. INVITE 4. AUTO-ANSWER 5. AUTO-ANSWER 6. AUTO-ANSWER 7. INVITE 10. OK 8. INVITE 9. OK 11. OK 12. OK 13. OK 14. Floor Status 15. Floor Status 105

106 Ad-hoc PoC Group Session (6/8) From PoC Client Pre-established Confirmed indication PoCClient A Home Network & Controlling Network PoC client A 1. REFER SIP/IP Core A PoC server A (participating & controlling) 4. ÁCCEPTED 2. REFER 3. ACCEPTED Invitations to the invited PoC subscriber 5. Floor Granted 6. Media First accepted invitation Optional If requested by the PoC client A 8. NOTIFY (result) 7. NOTIFY (result) Response for invitation When final response is received from an invited PoC subscriber, 106

107 Ad-hoc PoC Group Session (7/8) From PoC Client Pre-established Unconfirmed indication PoCClient A Home Network & Controlling Network PoC client A 1. REFER SIP/IP Core A PoC server A (participating & controlling) 4. ÁCCEPTED 2. REFER 3. ACCEPTED Invitations to the invited PoC subscriber 5. Floor Granted 6. Media First AUTO-ANSWER response 8. NOTIFY (result) 7. NOTIFY (result) Response for invitation 107

108 Ad-hoc PoC Group Session National Chung Cheng University (8/8) To PoC Client Pre-established Answer Confirmed OK Unconfirmed Auto Answer Since in this case the PoC client B is accepting the session automatically, or has authorised PoC Client A to issue a manual answer override request,and PoC client B has pre-established session with PoC server B (participating), the PoC Server B (participating) sends OK response back towards the controlling network. PoCclient A Home Network & Controlling Network SIP/IP Core A 1. INVITE 6. OK 108 PoC server A (participating & controlling) 2. INVITE 5. OK PoCClient B Home Netw ork PoC server B (participating) 3. INVITE 4. OK SIP/IP Core B 7. Floor Status 8. Floor Status PoC client B

109 Pre-arranged PoC Architecture PoC Server Controlling PoC Server Participating PoC Server PoC Server PoC Server Participating Participating Participating S-CSCF 1 I-CSCF 2 S-CSCF 2 SIP/IP Core SIP/IP Core SIP/IP Core SIP/IP Core P-CSCF 1 P-CSCF 2 UE 1 Watcher PoC Client Inviting PoC Subscriber PoC PoC Subscriber Subscriber Presence User Agent UE 2 Presentity 109

110 Pre-arranged PoC Group (1/5) A pre-arranged PoC group a group having pre-defined group identity and member list a pre-arranged PoC group session is initiated by one of the members established by using the group identity in the invitation message. The PoC Server X performs the necessary terminating service control authorizes the PoC Client A If the PoC address of the initiating user is authorized successfully, the PoC server X invites the other members to the PoC session 110

111 Pre-arranged PoC Group (2/5) Originating part On-demand Confirmed indication PoCClient A Home Network Controlling network PoC client A 1. INVITE SIP/IP Core A 2. INVITE PoC server A (participating) PoC server X (controlling) SIP/IP Core X 3. INVITE 4. INVITE 5. INVITE Invitation to the group members First accepted invitation 6. OK 7. OK 8. OK 9. OK 10. OK Floor control 111

112 Pre-arranged PoC Group (3/5) Terminating part Controlling Network PoCCl i ent B Home Network On-demand SIP/IP Core X PoC server X (controlling) PoC server B (participating) SIP/IP Core B PoC client B Manual answer 1. INVITE 2. INVITE 3. INVITE 4. INVITE 5. INVITE 7. Alerting 6. Alerting 8. Alerting 9. Alerting 10. Alerting 12. OK 13. Ok 11. OK 14. OK 15. OK Floor control 112

113 Pre-arranged PoC Group (4/5) Originating part On-demand Unconfirmed PoCClient A Home Network Controlling network PoC client A 1. INVITE SIP/IP Core A 2. INVITE 3. INVITE PoC server A (participating) PoC server X (controlling) SIP/IP Core X 4. INVITE 5. INVITE Invitation to the group members First auto-answer indication 6. Unconfirmed OK 7. Unconfirmed OK 8. Unconfirmed OK 9. Unconfirmed OK 10. Unconfirmed OK Floor control 113

114 Pre-arranged PoC Group (5/5) Terminating part Controlling Network PoCClient B Home Network On-demand SIP/IP Core X PoC server X (controlling) PoC server B (participating) SIP/IP Core B PoC client B Auto answer INVITE 1. INVITE 2. INVITE 3. INVITE 4. Auto-Answer 5. Auto-Answer 6. Auto-Answer 7. INVITE 8. INVITE 10. OK 9. OK 11. Ok 12. OK 13. OK 114

115 Chat PoC Group Session Join the Chat PoC Client A Home Network Controlling network PoC client A SIP/IP Core A PoC server A (participating) PoC server X (controlling) SIP/IP Core X 1. INVITE 2. INVITE The PoC Server X performs the necessary terminating service control (e.g. authorizes the PoC Client A) and if the PoC Address of the user initiating the PoC session is authorized successfully. The user is added to the Chat PoC Group session. 3. INVITE 8. OK 4. INVITE 7. OK 5. INVITE 6. OK 9. OK 10. OK 11. Floor control 115

116 Leaving PoC Group Session PoC Client A Home Network Controlling network PoC client A SIP/IP Core A PoC server A (participating) PoC server X (controlling) SIP/IP Core X Existing talk session Leaving-session-request 1. BYE Any group participant may leave the group session. 2BYE BYE 4. BYE When the PoC group session initiator leaves the group session, whether the group session is ended or not depends on the group policy. 8. OK 9. OK 7. OK 5. BYE 6. OK 10. OK 116

117 Re-joining i PoC Group Session PoCClient A Home Network Controlling network PoC client A SIP/IP Core A PoC server A (participating) PoC server X (controlling) SIP/IP Core X Rejoin-session-request 1. INVITE Existing talk session 2. INVITE When the user wishes to rejoin the PoC group session, he issues INVITE request to the PoC server. The PoC server adds the user to the PoC group session if it is still ongoing, otherwise it is rejected. 3. INVITE 8. OK 4. INVITE 7. OK 5. INVITE 6. OK 9. OK 10. OK Floor control 117

118 Group & List Management PoC Client A Home Network PoC Client A GLMS A 1. LIST MANAGEMENT LIST Management request include a. Group identity b. Group objectives: display name, group type, member list c. Indication: 2. OK Create, modify, retrieve or delete 118

119 PoC Media Flows One to one Media Network A PoC Client A PoC PoC PoC Server A ServerX Server B (Participating) (Controlling) (Participating) PoC Client B Controlling POC Function Participating POC Function A POC Client A PoC Server 1. Media 2. Media 3. Media 4. Media Network B Participatin g POC Function B POC Client B 119

120 PoC Media Flows One-to-many Media be used in PoC Sessions with Pre-arranged Groups, Ad Hoc groups or Chat groups PoC PoC PoC PoC Server A Server X Server B PoC PoC Client A (Participating) (Controlling) (Participating) Client B 1 Client B2 Network X Controlling POC Function Network A Participating POC Function A POC Client A 1. Media Network B 2. Media 3. Media 5. Media 4. Media Participating POC Function B POC Client B 6. Media 120

121 References for PoC Push to talk over Cellular (PoC) - Architecture Draft Version April 2004 Open Mobile Alliance: OMA-AD AD_PoC-V1_ D Push-to-talk over Cellular (PoC) Architecture PoC Release 2.0 Architecture V2.0.8 ( ) Comneon, Ericsson, Motorola, Nokia, Siemens PoC User Plane - Transport Protocol PoC Release 2.0 Transport Protocols V2.0.6 ( ) Comneon, Ericsson, Motorola, Nokia, Siemens 3GPP TR V1.0.0 ( ) 3GPP enablers for OMA PoC Services;Stage 2(Release 6) 121

122 Summary Deploying Push-to-talk over Cellular Incremental revenue, not to replace normal cellular l mobile communications service 122

123 Any yq Question? Mobile All-IP Networking Laboratory Department of Computer Science & Information Engineering