3rd International ICST Conference on COMmunication System SoftWAre and MiddlewaRE

Research Article

Multicast Instant Channel Change in IPTV Systems

  • @INPROCEEDINGS{10.1109/COMSWA.2008.4554442,
        author={Damodar Banodkar and K.K. Ramakrishnan and Shivkumar Kalyanaraman and Alexandre Gerber and Oliver Spatscheck},
        title={Multicast Instant Channel Change in IPTV Systems},
        proceedings={3rd International ICST Conference on COMmunication System SoftWAre and MiddlewaRE},
        keywords={Display Latency Channel switching Latency Bandwidth IPTV.},
  • Damodar Banodkar
    K.K. Ramakrishnan
    Shivkumar Kalyanaraman
    Alexandre Gerber
    Oliver Spatscheck
    Year: 2008
    Multicast Instant Channel Change in IPTV Systems
    DOI: 10.1109/COMSWA.2008.4554442
Damodar Banodkar1,*, K.K. Ramakrishnan2,*, Shivkumar Kalyanaraman1,*, Alexandre Gerber2,*, Oliver Spatscheck2,*
  • 1: Rensselaer Polytechnic Institute (RPI)
  • 2: AT&T Labs Research
*Contact email: banodd@rpi.edu, kkrama@research.att.com, shivkuma@ecse.rpi.edu, gerber@research.att.com, spatsch@research.att.com


IPTV delivers television content over an IP infrastructure with the potential to enrich the viewing experience of users by integrating data applications with video delivery. From an engineering perspective, IPTV places both significant steady state and transient demands on network bandwidth. Typical IPTV streaming techniques incur delays to fill the play-out buffer. But, when viewers switch or surf channels, it is important to minimize this user-perceived latency. Traditional Instant Channel Change (ICC) techniques reduce this latency by having a separate unicast assist channel for every user changing channels. Instead, we propose a multicast-based approach using a secondary "channel change stream" in association with the multicast of the regular quality stream for the channel requested. During channel change events, the user does a multicast join to this new stream and experiences smaller display latency. In the background, the play-out buffer of the new full-quality multicast stream is filled. Then, the transition to the new channel is complete. We show that this approach has several performance benefits including lower bandwidth consumption even during flash crowds of channel changes, lower display latency (50% lower), and lower variability of network & server load. The tradeoff is a lower quality video during the play-out buffering period of a few seconds. Our results are based upon both synthetic channel change arrival patterns as well as traces collected from an operational IPTV environment.