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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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Overview of IPTV Architecture

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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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Physical Model

B1N B1S

B2S

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P2P Sharing within a Community

Bottleneck

Not beneficial

B1SB1N

B2S

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P2P Sharing within a Community

Bottleneck

Beneficial

B1SB1N

B2S

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P2P Sharing across Communities

Bottleneck

Not beneficial

or B1SB1N

B2S

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Simulation Setup

B2S: 10 Gbps

Content server(1000 programs, 120 mins, 6 Mbps)

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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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Profit Per Unit Time

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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”