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

Outline

• Motivation• ACT design– Conferences discovery– Speakers discovery– Voice data distribution

• Discussion– Security, scalability, robustness, mobility

• Conclusion

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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

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Outline

• Motivation• ACT design– Conferences discovery– Speakers discovery– Voice data distribution

• Discussion– Security, scalability, robustness, mobility

• Conclusion

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Difference in communica-tion

Cen-tral

server

B

D

A C

B

D

A C

Speaker Speaker

Traditional audio conference ACT

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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 inter-face design

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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

Conferences discovery

• Conference announcement– Creating a data object in the Session De-

scription 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

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Conference discovery

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/ndn/broadcast/conference/conference-list/icn2011

/ndn/broadcast/conference/conference-list/ndn/broadcast/conference/conference-listExclude filter = [icn2011]

Speakers discovery

• Using similar mechanism with con-ference discovery– Ex) /ndn/broadcast/conferences/[confer-

ence-name]/speaker-list

• ACT scales well– ACT tracks only speakers, not all partici-

pants

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Voice data distribution

• Each speaker uses a topology-de-pendent 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

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Outline

• Motivation• ACT design– Conferences discovery– Speakers discovery– Voice data distribution

• Discussion– Security, scalability, robustness, mobility

• Conclusion

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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

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Security

• Supporting private conference– Data authentication

• Legitimate participants send Interest for the conference’s public key

• Conference initiator knows the list of legiti-mate participants, and responds with confer-ence’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

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Other discussions

• Scalability– Traditional: Central server may be bot-

tleneck– ACT: No repeated packet by pending

• Robustness– Traditional: Central server may be a sin-

gle point of failure– ACT: Fully distributed

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Other discussions

• Mobility– Traditional: Re-register with new IP ad-

dress and restart joining process– ACT• Listener: Nothing needs to be changed• Speaker: Appending “#” to moving

speaker’s name

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Conclusion

• Designing ACT, a completely distrib-uted audio conference tool using NDN– Good example on how to design applica-

tions over NDN– Useful tool for research collaborations

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