ACT: Audio Conference Tool Over Named Data Networking

1. ACT: Audio Conference Tool Over Named Data Networking Zhenkai Zhu, Sen Wang, Xu Yang, Van Jacobson, Lixia Zhang ICN ‘11 August 19 Presenter: Junghwan Song

2. Outline • Motivation • ACT design • Conferences discovery • Speakers discovery • Voice data distribution • Discussion • Security, scalability, robustness, mobility • Conclusion

3. Motivation • To gain further understanding • Application data naming • Relation with routing scalability • Trust model • To serve as a useful tool for the NDN team collaborations • To generate real-world traffic on an NDN testbed

4. Outline • Motivation • ACT design • Conferences discovery • Speakers discovery • Voice data distribution • Discussion • Security, scalability, robustness, mobility • Conclusion

5. Difference in communication Traditional audio conference ACT B B Central server A C A C Speaker Speaker D D

6. An overview of ACT design • Basic tasks of ACT • Collecting the latest information about all existing conferences • List of conferences, speakers • Using two different name space • Media data processingand user interface design

7. An overview of ACT design • Open source audio conference package • To focus on NDN • Change server codes • Embedding speakers discovery, voice data distribution • Conference discovery module is separated • Flexible to extend ACT with other features

8. Conferences discovery • Conference announcement • Creating a data object in the Session Description Protocol(SDP) • Ex) /ndn/broadcast/conference/conference-list/icn2011 • Conference enumeration • Sending interests with broadcast name • Ex) /ndn/broadcast/conference/conference-list • To get all conferences, using exclusion filter

9. Conference discovery /ndn/broadcast/conference/conference-list/icn2011 /ndn/broadcast/conference/conference-list /ndn/broadcast/conference/conference-list Exclude filter = [icn2011]

10. Speakers discovery • Using similar mechanism with conference discovery • Ex) /ndn/broadcast/conferences/[conference-name]/speaker-list • ACT scales well • ACT tracks only speakers, not all participants

11. Voice data distribution • Each speaker uses a topology-dependent name prefix • Ex) /ucla.edu/cs/zhenkai/[device-id]/[codec-name]/[seg-num] • Device-id: 32-bit random string, unique in local network • Seg-num: Incremental number stored in a circular buffer • Each interest retrieves a data packet • Pipelining can be used

12. Outline • Motivation • ACT design • Conferences discovery • Speakers discovery • Voice data distribution • Discussion • Security, scalability, robustness, mobility • Conclusion

13. Security • Two basic security functions • Data authentication • Participants control • ACT’s way of supporting security • There’re built-in security primitives in NDN • Using encryption-based access control scheme

14. Security • Supporting private conference • Data authentication • Legitimate participants send Interest for the conference’s public key • Conference initiator knows the list of legitimate participants, and responds with conference’s private key • Initiator encrypts a session key using public key and publishes it under a name • Participants control • Do not respond to unauthorized users

15. Other discussions • Scalability • Traditional: Central server may be bottleneck • ACT: No repeated packet by pending • Robustness • Traditional: Central server may be a single point of failure • ACT: Fully distributed

16. Other discussions • Mobility • Traditional: Re-register with new IP address and restart joining process • ACT • Listener: Nothing needs to be changed • Speaker: Appending “#” to moving speaker’s name

17. Conclusion • Designing ACT, a completely distributed audio conference tool using NDN • Good example on how to design applications over NDN • Useful tool for research collaborations