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Case Study: Resilient Backbone Design for IPTV Services. Meeyoung Cha, Gagan Choudhry, Jennifer Yates, Aman Shaikh and Sue Moon Presented by Yuanbin Shen March 25, 2009. Introduction. Nation-wide TV broadcast Satellite-based Terrestrial-based (typically over IP networks → IPTV)
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Case Study: Resilient Backbone Design for IPTV Services Meeyoung Cha, Gagan Choudhry, Jennifer Yates, Aman Shaikh and Sue Moon Presented by Yuanbin Shen March 25, 2009
Introduction • Nation-wide TV broadcast • Satellite-based • Terrestrial-based (typically over IP networks → IPTV) • IPTV architectural design • Integrate IPTV services with existing IP backbone • Construct a dedicated overlay network on top of IP • Construct a direct interconnected flat IP network • Integrate with an existing switched optical network What is the best architecture for supporting IPTV?
IPTV Traffic • Type • Broadcast TV: realtime • VoD download: non-realtime download to VHOs • Realtime VoD: realtime • Characteristics • Uni-directional and high-bandwidth • VoD traffic: highly variable • Multicast for broadcast TV / unicast for VoD
Design Options • Technology: • layer1 (optical) v.s. layer3 (IP/MPLS) • Topology: • hub-and-spoke v.s. meshed
Design Options (cont’d) • Access connections Failure working path • Failure recovery Src Dst working path Failure Src Dst protection path switching IP layer fast-reroute (FRR) Optical layer SONET protection
Model 1: Integrate With Existing IP Backbone • Backbone links are shared and access links are dedicated • Rapid deployment: using existing infrastructure • High resource utilization: share bandwidth between applications • Drawback: IPTV quality easily impacted by Internet traffic
Model 2: Dedicated Overlay • Use common backbone routers to construct dedicated IPTV overlay • Easy for performance management: links are dedicated • Overhead to construct the overlay
Model 3: Flat IP (No backbone) Services routers (SR) directly connected using point-to-point links over dense wavelength division multiplexors (DWDMs) Connect geographically close VHOs into regional rings Inter-connect rings with long super links No existing infrastructure used SHO SHO VHO Long super links
Model 4: Integrate with switched optical network Multicast capabilities at optical nodes (new technology) SHOs establish multicast trees, VHO receiving single best stream Failure recovery: rapid switch between different paths How to find physically-diverse paths from SHOs to each VHO? → NP-hard → use IP-based approach to create trees SHO SHO L1 network VHO
Design Instances model.1 model.2 model.3 model.4
Evaluation- Cost (capital) comparison of multicast and unicast • Multicast is much more economical than unicast • Optical network is more economical than IP network
Evaluation- Cost (capital) comparison across design instances • Optical networks are more economical than IP networks • Total cost is dominated by access cost (except for IP flat design) • Ring access is good of multicast; dual-homed access is good for unicast(VoD) • For backbone cost, the flat IP model is the most expensive
Conclusion • Explore potential IPTV designs in backbone network • Comparison across different design architectures • Significant benefits of using multicast for broadcast TV • Optical design more economical than IP designs • Ring access attractive for broadcast TV; dual-homed access attractive for VoD
When is P2P Technology Beneficial for IPTV Services? Yin-Farn Chen, Yennun Huang, Rittwik Jana, Hongbo Jiang, Michael Rabinovich, Bin Wei and Zhen Xiao Presented by Yuanbin Shen March 25, 2009
Introduction • Problems in providing IPTV: • high deployment and maintenance cost • Server bandwidth limits • One solution → using P2P technology • Does P2P technology always works well for IPTV? When is it beneficial? • Network models • Cloud model: overestimate P2P benefits • Physical model: more practical • Provide three incentive models to encourage P2P sharing in IPTV under a physical model
Cloud Model • Simple for modeling • Does not consider the constraints of the underlining service infrastructure
Physical Model B2S B1N B1S
P2P Sharing within a Community B2S B1N B1S Bottleneck Not beneficial
P2P Sharing within a Community B2S B1N B1S Bottleneck Beneficial
P2P Sharing across Communities B2S B1N B1S or Bottleneck Not beneficial
Simulation Setup B2S: 10 Gbps Content server (1000 programs, 120 mins, 6 Mbps)
Simulation Setup 20 communities Content server (1000 programs, 120 mins, 6 Mbps) B1S B2S: 10 Gbps B1N: 0.622 Gbps
Results: cloud model v.s. physical model -1 Links across communities are heavily utilized. Limited by B1N Total # of peers: 20*community size
Results: cloud model v.s. physical model -2 Don’t consider the bandwidth in the cloud Traffic across communities increases Limited by B2S Total # of peers: 10000 Community size: 500
Results: cloud model v.s. physical model -3 Serves all active viewers Limited by B1N Limited by B1N, traffic across communities reduces the bandwidth Total # of peers: 10000 Community size: 500
Cost-Benefic Analysis • Maximum Profit for Conventional IPTV • Pnop2p = rN – Enop2p • P2P Incentive Models • Built-in Model: • Pb = rN – Enop2p – tN • r: fee paid by a viewer • N: number of viewers • tN: P2P installation expense
Cost-Benefic Analysis • Flat-reward Model: • Pf = rN – Enop2p – twN – dwN • w: percent of viewers sign up for P2P • d: reward per P2P user • Usage-based Model • Ps = rN – Enop2p – tN – qbuTN • u: average video rate • T: program length • q: credit per bit • b: percent of viewers download data from peers
Simulation Results (Using MediaGrid Algorithm) When system is sufficiently utilized When system is under utilized • More peers → more benefits from P2P • Large differences among incentive models • Build-in model is the best under this setup • non-P2P may be better than P2P
Conclusion • Studied when P2P is beneficial for IPTV • Cloud model may overstate P2P benefits → use physical model • Different incentive strategies lead to different profits → choose a proper one for specific application.
References • M. Cha, G. Choudhury, J. Yates, A. Shaikh, and S. Moon, “Case Study: Resilient Backbone Design for IPTV Services”, In Proc. of International Workshop on Internet Protocol TV Services over World Wide Web, May 2006 • M. Cha, G. Choudhury, J. Yates, A. Shaikh, and S. Moon, Slides: “http://an.kaist.ac.kr/~mycha/docs/mycha_www_iptv06.ppt” • Y. Chen, Y. Huang, R. Jana, H. Jiang, M. Rabinovich, B. Wei, and Z. Xiao, “When is P2P Technology Beneficial for IPTV Services,” ACM NOSSDAV, June 2007. • Meng-Ting Lu, Slides: “When is P2P Technology Beneficial for IPTV Services,” http://nslab.ee.ntu.edu.tw/OESeminar/slides/When is P2P Technology Beneficial for IPTV Services.ppt”