1. 1/32 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

2. 2/32 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?

3. 3/32 Overview of IPTV Architecture

4. 4/32 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

5. 5/32 Design Options Technology:  layer1 (optical) v.s. layer3 (IP/MPLS) Topology:  hub-and-spoke v.s. meshed

6. 6/32 Design Options (cont ’ d) working path Src Dst Failure switching Optical layer SONET protection Src Dst working path protection path IP layer fast-reroute (FRR) Failure Access connections Failure recovery

7. 7/32 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

8. 8/32 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

9. 9/32 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 Long super links SHO VHO

10. 10/32 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 L1 network VHO

11. 11/32 Design Instances DesignLayerLink-CapacityAccess TypeFast-failover Int-IP-HS Int-IP-HS-FRR Int-IP-Ring Int-IP-Ring-FRR IP.. Shared.. Dual-homed.. Ring.. SONET links Fast re-route SONET links Fast re-route Ded-IP-HS Ded-IP-HS-FRR Ded-IP-Ring Ded-IP-Ring-FRR IP.. Dedicated.. Dual-homed.. Ring.. SONET links Fast re-route SONET links Fast re-route P2P-DWDM P2P-DWDM-FRR IP.. Dedicated.. None.. SONET links Fast re-route Opt-SwitchedOpticalTime-divisionedDual-homedDisjoint paths model.1 model.2 model.3 model.4

12. 12/32 Evaluation - Cost (capital) comparison of multicast and unicast Multicast is much more economical than unicast Optical network is more economical than IP network

13. 13/32 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

14. 14/32 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

15. 15/32 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

16. 16/32 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

17. 17/32 Cloud Model Simple for modeling Does not consider the constraints of the underlining service infrastructure

18. 18/32 Physical Model B 1N B 1S B 2S

19. 19/32 P2P Sharing within a Community Bottleneck Not beneficial B 1S B 1N B 2S

20. 20/32 P2P Sharing within a Community Bottleneck Beneficial B 1S B 1N B 2S

21. 21/32 P2P Sharing across Communities Bottleneck Not beneficial or B 1S B 1N B 2S

22. 22/32 Simulation Setup B 2S : 10 Gbps Content server (1000 programs, 120 mins, 6 Mbps)

23. 23/32 Simulation Setup B 1N : 0.622 Gbps B 1S B 2S : 10 Gbps 20 communities Content server (1000 programs, 120 mins, 6 Mbps)

24. 24/32 Links across communities are heavily utilized. Limited by B 1N Total # of peers: 20*community size Results: cloud model v.s. physical model -1

25. 25/32 Don’t consider the bandwidth in the cloud Traffic across communities increases Limited by B 2S Total # of peers: 10000 Community size: 500 Results: cloud model v.s. physical model -2

26. 26/32 Serves all active viewers Limited by B 1N, traffic across communities reduces the bandwidth Limited by B 1N Total # of peers: 10000 Community size: 500 Results: cloud model v.s. physical model -3

27. 27/32 Cost-Benefic Analysis Maximum Profit for Conventional IPTV  P nop2p = rN – E nop2p P2P Incentive Models  Built-in Model:  P b = rN – E nop2p – tN  r: fee paid by a viewer  N: number of viewers  tN: P2P installation expense

28. 28/32 Cost-Benefic Analysis  Flat-reward Model:  P f = rN – E nop2p – twN – dwN  w: percent of viewers sign up for P2P  d: reward per P2P user  Usage-based Model  P s = rN – E nop2p – tN – qbuTN  u: average video rate  T: program length  q: credit per bit  b: percent of viewers download data from peers

29. 29/32 Profit Per Unit Time

30. 30/32 Simulation Results (Using MediaGrid Algorithm)  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 When system is sufficiently utilizedWhen system is under utilized

31. 31/32 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.

32. 32/32 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”