1. IPTComm2007 -- New York City, July 19th 20071 Improving the scalability of an IMS-compliant conferencing framework through presence and event notification IPTComm2007 New York, July 19 th 2007 A. Amirante, T. Castaldi, L. Miniero and S.P. Romano COMICS (COMputers for Interaction and CommunicationS) research group University of Napoli Federico II

2. IPTComm2007 -- New York City, July 19th 2007 2 Agenda Rationale & Motivation A standard centralized conferencing architecture Performance assessment and bottlenecks identification Improving scalability through distribution of components/responsibilities Conclusions

3. IPTComm2007 -- New York City, July 19th 2007 3 Conference The term Conference can be used to describe any meeting of people that confer about a certain topic Web Conferencing is used to indicate live meetings or presentations over the Internet

4. IPTComm2007 -- New York City, July 19th 2007 4 Standardization efforts No standardization for many years Lack of interoperability Platform dependency Security issues Cost Market segmentation Standardization Bodies ITU (International Telecommunication Union) IETF (Internet Engineering Task Force) 3GPP (3rd Generation Partnership Project)

5. IPTComm2007 -- New York City, July 19th 2007 5 IETF SIPPING Working Group Session Initiation Proposal Investigation Documents the use of SIP for several applications related to telephony and multimedia SIP Conferencing Loosely-Coupled ConferenceFully Distributed Multiparty Conference Tightly-Coupled Conference Focus Policy Server Mixer Notification Service (Event Package, RFC 4575) Participants SIP Conferencing Framework (RFC 4353): fundamental elements

6. IPTComm2007 -- New York City, July 19th 2007 6 XCON Working Group Centralized Conferencing (XCON) Extends RFC 4353 Protocol-agnostic (not only SIP) Data Sharing (not only audio/video) Suite of Protocols Conference Control (CCMP?) Floor Control (BFCP) Call Signaling (SIP/H.323/IAX/etc.) Notification (Event Package?)

7. IPTComm2007 -- New York City, July 19th 2007 7 XCON Framework Conference Control Client Floor Control Client Call Signaling Client Notification Client Conference Control Server Floor Control Server Focus Notification Service Conference Object Conference Control Protocol Floor Control Protocol Call Signaling Protocol Notification Protocol Conferencing System Conferencing Client

8. IPTComm2007 -- New York City, July 19th 2007 8 CONFIANCE CONFerencing IMS-enabled Architecture for Next-generation Communication Experience http://confiance.sourceforge.net/ Open source implementation of the XCON Framework, compliant with the IMS specification Extends the Asterisk PBX functionality Enhanced MeetMe application Support for Conference Management (Scheduler) Support for Floor Control (BFCP) Support for BFCP-guided video switching/mixing Support for MSRP (Message Session Relay Protocol) text chatrooms

9. IPTComm2007 -- New York City, July 19th 2007 9 CONFIANCE in IMS

10. IPTComm2007 -- New York City, July 19th 2007 10 Why Distributed Conferencing? Centralized Conferencing Poorly scalable Limited capabilities Single point of failure Towards distribution: Cascaded Conferencing Each focus is seen as a participant by the others Only affects mixers' distribution Centralized protocols like BFCP don't work

11. IPTComm2007 -- New York City, July 19th 2007 11 DCON Proposal Distributed Conferencing (DCON) http://dcon.sourceforge.net/ Orchestrates the operation of a set of XCON clouds Overlay network interconnecting the clouds Intra-focus communication Still based on XCON protocols Inter-focus communication Exploits Server-to-Server (XMPP) Requirements Focus discovery Initialization information & spreading of conference events Setup and managing of distributed conferences Transparent dispatching of natively centralized protocols among the involved conferencing clouds XMPP SIP

12. IPTComm2007 -- New York City, July 19th 2007 12 DCON Implementation

13. Wildfire connection to Asterisk Gateway MeetMe Manager Dispatcher Presence Manager Memory S2S manager Sip Client XMPP Client Focus XCON We suppose CONFIANCE is working When the DCON component starts, 3 main events happen: 1)Connection to the Asterisk Manager interface 2)Connection to the Gateway interface 3)Request for initialization information Now the focus cloud involves also the Wildfire server and SPACE component which has in charge: 1)Discovery of other foci 2)Management of DCON information and BFCP packets. Focus DCON Wildfire DCON enabled CONFIANCE Updating… Update QueryUpdate ActiveRegistered 86712348672000 ActiveRegistered 86712348672000

14. IPTComm2007 -- New York City, July 19th 2007 14 Tool employed: SIPp SIP traffic generator Capable to reproduce fully customizable call scenarios through XML configuration scripts Capable to also reproduce actual media flows through the RTP/pcap replay function Used to test two different facets of scalability: Maximum number of users who can access the system Resource consumption, given a specific number of users Testbed: OS: Linux Fedora Core 6, kernel 2.6.15 CPU 3,2GHz Intel XEON, RAM 2GB Performance assessment

15. IPTComm2007 -- New York City, July 19th 2007 15 Asterisk does not allow to open more than 1024 Zaptel pseudo-channels (i.e. abstractions of physical channels) simultaneously Each conference, upon creation, makes use of two such channels Each conference participant uses a single pseudo- channel Quasi-linear growth in the number of users in the presence of distribution Note well: No RTP traffic involved in such tests just signaling! Scalability: just signaling

16. IPTComm2007 -- New York City, July 19th 2007 16 Centralized case (one single conference) FocusCallsCPU load (%) Main30099,4 300 users as a maximum limit in the presence of audio streams Might become critical in case many conferences are activated in a cloud A reference value for the following tests Scalability: signalling + audio

17. IPTComm2007 -- New York City, July 19th 2007 17 FocusCallsCPU load (%) Main15030,04 Remote15020,19 Scalability: 2 islands case

18. IPTComm2007 -- New York City, July 19th 2007 18 FocusCallsCPU load (%) Main10020 Remote_110018 Remote_210018 FocusCallsCPU load (%) Main15031,05 Remote_17512 Remote_27512 Scalability: 3 islands case

19. IPTComm2007 -- New York City, July 19th 2007 19 Migration towards a distributed paradigm allows for a huge reduction in the load of the primary focus The sum of the CPU levels of all involved foci is less than the CPU level of the single focus in the centralized case Given a fixed number of local users, remote users distribution among multiple islands adds negligible overhead to the main focus Scalability: figures in summary

20. IPTComm2007 -- New York City, July 19th 2007 20 Future Work More performance tests: Different media: Involve video, chat, desktop sharing applications, etc. in the trials Different protocols Involve BFCP, Conference Control Protocol, etc. in the trials Different scenarios Try to reproduce real-world conference configurations Different overlay topologies Not just full meshes Investigate smart p2p approaches

21. IPTComm2007 -- New York City, July 19th 2007 21 What else? See all of you at the demo tomorrow! Have a look at DCON up and (hopefully ) running… We also present: our brand new JAVA-based integrated client our current prototype of the distributed approach to video mixing Our contacts: tobia.castaldi@unina.it lorenzo.miniero@unina.it spromano@unina.it alex.amirante@tin.it