Contents

1. Membership and Media Management in Centralized Multimedia Conferences based on Internet Engineering Task Force Protocol Building BlocksAuthor: Ritu MittalSupervisor: Prof. Jörg OttInstructor: Gonzalo CamarilloOy LM Ericsson AB Finland Networking Laboratory

2. Contents • Objectives • Introduction • Conferencing frameworks • Conference control protocol • Conference control protocol proposals over IETF • Conference control protocol proposal in this thesis • Prototype implementation • conclusion Networking Laboratory

3. Objective • Theoretical Part of this thesis • Analysis of different Conference Control Protocol proposals over Internet Engineering Task Force (IETF) Centralized Conferencing (XCON) Working Group. • Proposing a conference control mechanism • Practical part of this thesis • Implementation of the Conference Server using Session Initiation Protocol (SIP) on the existing Session Border Gateway (SBC) for establishing signaling connection between the conference clients and the server itself. Networking Laboratory

4. Introduction • Session Initiation Protocol (SIP) is the most widely used telephony standard • Multimedia conferencing using SIP is becoming popular • But offering conference control services which means that managing members and their media in a conference session is out of the scope of SIP. • There are some non-SIP Conference control protocol Proposals over IETF XCON WG for the conference control. Networking Laboratory

5. Conferencing Models Fully-distributed tightly-coupled Loosely-coupled Networking Laboratory

6. Conferencing Frameworks (1) • There are two conferencing frameworks defined by IETF • The frameworks defines the logical entities and terminology used for conferencing • The SIPPING Conferencing framework • The XCON Conferencing framework • SIPPING uses SIP as the signaling protocol • XCON framework is independent of the signaling protocol used e.g. Can use H.323 , SIP or PSTN • the XCON framework is compatible with SIPPING framework Networking Laboratory

7. Conferencing Frameworks (2) • The central component in the conferencing framework is a conference server called focus • A participant contact to the Focus by using a unique Conference URI e.g. Sip: myconference@sip.com • It maintains a signaling relationship with each conference participant • Responsible for media streams in the session • Responsible for conference policies, notifications about the state changes in a conference • It contains common conference information about signaling, members, media streams etc. known as conference object • Common conference Information is represented by data elements and their attributes known as components • Only the authorized participants can access and manipulate those components • Needs a non-SIP conference control protocol to access and manipulate it. Networking Laboratory

8. Conferencing Frameworks (3) • General arrangement of different entities for a conference call Networking Laboratory

9. Conferencing Frameworks (4) • Conference policy: A complete set of rules for a particular conference, includes • Membership Policy (rules about participation in a conference) • Media Policy (multiple media types e.g. Audio,video etc.) • An participant becomes authorized if conference policy allows him to make the changes in the common conference information • Conference policy is an integral pat of the conference object Networking Laboratory

10. Conference Control Protocol (CCP) • It defines an interface between the conferencing client and the conference server to access and manipulate common conference information. • Provides overall control over the members and media of a conference • For example: add, delete and modify members and their media in a conference • Performs advaced conference control services e.g. Mute a noisy participant, change the size of video display, increase/decrease the volume of the conference session etc. Networking Laboratory

11. Conference Control Protocol (2) Networking Laboratory

12. Conference control Protocol Proposals over IETF XCON (1) • Conference policy control protocol (CPCP) • Conference state change protocol (CSCP) • Centralized Conference Manipulation Protocol (CCMP) • Centralized Conference Control Protcol (CCCP) • Every protocol has its own way to access and modify (manipulate) the common conference information represented by conference object. • We analyse them on the basis of their syntactic vs. Semantic properties. • CPCP and CSCP uses syntactic approach • CCMP and CCCP used semantic approach Networking Laboratory

13. Semantic Vs. Syntactic Approach Syntactic Semantic a client sends pre-defined or dedicated primitives, e.g. <adduser>, <modifymedia>, <increaseConferenceVolume> etc. The server can store the conference information in any format. The confernce server should support all the primitves used by the client Scope is limited to only one application A client can extend or define new primitives even to modify small information • A client performs add/delete/modify operations on the elements and their attributes of conference information. • The client should have an complete understanding of the format used by the server to store the information. • Modifying too many separated elements at the same time needs more network resources e.g. Bandwidth • Scope is wide and can be used for multiple applications. • a client have to define the whole path to modify the small information Networking Laboratory

14. Conference control protoocol Proposal in this thesis(1) • We proposed a Centralized Conference Object Manipulation Protocol (CCOMP) • It is not a new protocol • Have features of CCMP and CCCP • Uses conference control operations in the request • E.g. OPTIONS, GET, CREATE, MODIFY, DELETE • Conveys to the server about the operation a client wants to perform. • Based on their semantic properties • Used pre-defined and dedicated primitives • Primtives can be extended • Client-server model • Client send a request towards the server • Server responds with the response code of ”Success or Failure” • this maintains transparency bewteen them • Independent of underlying transport protocol • e.g can use HTTP or SOAP • Uses multiple primitives inside a single request • Saves network bandwidth • Conferencekeys: confEntity=sip:conf123@sip.com identifies directly a particular conference Networking Laboratory

15. Conference control protoocol Proposal in this thesis(2) • CCOMP Operation=CREATE Networking Laboratory

16. Practical part Prototype Implementation The objective of the practical part is to implement the conference server (foucs) functionality on an existing Session Border Controller. SBC is used to manage signaling and media streams in a Voice-over-IP network. It supports small-scale multimedia conference calls. Networking Laboratory

17. Session setup Example SIP Message: INVITE sip:conference@131.160.36.20:5060 SIP/2.0 Via: SIP/2.0/UDP 127.0.0.2:5064 From: sipp <sip:sipp@127.0.0.2:5064>;tag=1 To: <sip:conference@131.160.36.20:5060> Call-ID: 1-11355@127.0.0.2 CSeq: 1 INVITE Contact: sip:sipp@127.0.0.2:5064 Max-Forwards: 70 Subject: Performance Test Content-Type: application/sdp Content-Length: 134 v=0 o=user1 53655765 2353687637 IN IP4 127.0.0.1 s=- c=IN IP4 131.160.36.20 t=0 0 m=audio 30105 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Networking Laboratory

18. Conclusion • Theoreical part • Analysis of various conference control protocol proposals over IETF XCON WG. • Proposed semantic-based CCOMP, combination of two of existing protocol proposals i.e. CCMP and CCCP. • Practical Part • The implemenation of SIP Conference server over existing SBC is successfully implemented. • Future Work • Interface between the conference server and media server which is known as media control protocol • Implementing conference control fuctionality into SBC • One CCP for the interface between the client and conference server, and between the conference server and the media server Networking Laboratory