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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 ShenMarch 25, 2009
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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?
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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
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Design Options
Technology: layer1 (optical) v.s. layer3 (IP/MPLS)
Topology: hub-and-spoke v.s. meshed
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Design Options (cont’d)
working pathSrc
Dst
Failure
switching
Optical layer SONET protection
Src Dst
working path
protection path IP layer fast-reroute (FRR)
Failure
Access connections
Failure recovery
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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
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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
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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
SHO
VHO
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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
SHOSHO
L1 network
VHO
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Design Instances
Design Layer Link-Capacity Access Type Fast-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-Switched Optical Time-divisioned Dual-homed Disjoint paths
model.1
model.2
model.3
model.4
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Evaluation- Cost (capital) comparison of multicast and unicast
Multicast is much more economical than unicast Optical network is more economical than IP networ
k
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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 uni
cast(VoD) For backbone cost, the flat IP model is the most expensive
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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-home
d access attractive for VoD
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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 ShenMarch 25, 2009
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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
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Cloud Model
Simple for modeling Does not consider the constraints of the underlining
service infrastructure
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Simulation Setup
B1N: 0.622 Gbps
B1S
B2S: 10 Gbps
20 communities
Content server(1000 programs, 120 mins, 6 Mbps)
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Links across communitiesare heavily utilized.
Limited by B1N
Total # of peers:20*community size
Results: cloud model v.s. physical model -1
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Don’t consider the bandwidth in the cloud
Traffic across communities increases
Limited by B2S
Total # of peers: 10000Community size: 500
Results: cloud model v.s. physical model -2
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Serves all active viewers
Limited by B1N, traffic across communities reduces the bandwidth
Limited by B1N
Total # of peers: 10000Community size: 500
Results: cloud model v.s. physical model -3
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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
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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
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Simulation Results (Using MediaGrid Algorithm)
More peers → more benefits from P2P Large differences among incentive modelsBuild-in model is the best under this setup
non-P2P may be better than P2P
When system is sufficiently utilized When system is under utilized
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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.
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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”