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 2/17

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 3/17

4. Outline Motivation ACT design –Conferences discovery –Speakers discovery –Voice data distribution Discussion –Security, scalability, robustness, mobility Conclusion 4/17

5. Difference in communication Central server B B D D A A C C B B D D A A C C Speaker Traditional audio conference ACT 5/17

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 processing and user interface design 6/17

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 7/17

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 8/17

9. Conference discovery 9/17 /ndn/broadcast/conference/conference-list/icn2011 /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 10/17

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 11/17

12. Outline Motivation ACT design –Conferences discovery –Speakers discovery –Voice data distribution Discussion –Security, scalability, robustness, mobility Conclusion 12/17

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 13/17

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 14/17

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 15/17

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 16/17

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 17/17