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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 1/32 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? 2/32 Overview of IPTV Architecture 3/32 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 4/32 Design Options Technology: layer1 (optical) v.s. layer3 (IP/MPLS) Topology: hub-and-spoke v.s. meshed 5/32 Design Options (cont’d) Access connections Failure working path Failure recovery Src Dst working path Failure Src Dst protection path IP layer fast-reroute (FRR) switching Optical layer SONET protection 6/32 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 7/32 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 8/32 Model 3: Flat IP (No backbone) SHO SHO VHO Long super links 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 9/32 Model 4: Integrate with switched optical network SHO SHO L1 network VHO 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 10/32 Design Instances Design Int-IP-HS model.1 Int-IP-HS-FRR Int-IP-Ring Int-IP-Ring-FRR Ded-IP-HS model.2 Ded-IP-HS-FRR Ded-IP-Ring Ded-IP-Ring-FRR Layer Link-Capacity Access Type Fast-failover IP .. .. .. Shared .. .. .. Dual-homed .. Ring .. SONET links Fast re-route SONET links Fast re-route IP .. .. .. Dedicated .. .. .. Dual-homed .. Ring .. SONET links model.3 P2P-DWDM IP P2P-DWDM-FRR .. model.4 Opt-Switched Optical Fast re-route SONET links Fast re-route Dedicated .. None .. SONET links Fast re-route Time-divisioned Dual-homed Disjoint paths 11/32 Evaluation - Cost (capital) comparison of multicast and unicast Multicast is much more economical than unicast Optical network is more economical than IP network 12/32 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 13/32 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 14/32 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 15/32 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 16/32 Cloud Model Simple for modeling Does not consider the constraints of the underlining service infrastructure 17/32 Physical Model B2S B1N B1S 18/32 P2P Sharing within a Community B2S B1N B1S Bottleneck Not beneficial 19/32 P2P Sharing within a Community B2S B1N Bottleneck B1S Beneficial 20/32 P2P Sharing across Communities B2S B1N or B1S Bottleneck Not beneficial 21/32 Simulation Setup B2S: 10 Gbps Content server (1000 programs, 120 mins, 6 Mbps) 22/32 Simulation Setup 20 communities Content server (1000 programs, 120 mins, 6 Mbps) B1S B2S: 10 Gbps B1N: 0.622 Gbps 23/32 Results: cloud model v.s. physical model -1 Links across communities are heavily utilized. Limited by B1N Total # of peers: 20*community size 24/32 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 25/32 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 26/32 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 27/32 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 28/32 Profit Per Unit Time 29/32 Simulation Results (Using MediaGrid Algorithm) When system is sufficiently utilized More peers → more benefits from P2P Large differences among incentive models Build-in model is the best under this setup When system is under utilized non-P2P may be better than P2P 30/32 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. 31/32 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” 32/32