1. P2P vs CDN: An Industry Perspective Pei Cao

2. P2P CDNs With the exception of Skype, almost all P2P systems are essentially content distribution networks (CDNs) With the exception of Skype, almost all P2P systems are essentially content distribution networks (CDNs) Kazaa, BitTorrent, etc.Kazaa, BitTorrent, etc. The Cost-Transfer Effect: the cost of content distribution is borne by the network provider, not the content provider The Cost-Transfer Effect: the cost of content distribution is borne by the network provider, not the content provider vs. itunes, YouTube, etc.vs. itunes, YouTube, etc.

3. Legal CDNs Cache-based CDNs are the most network- efficient delivery mechanism Cache-based CDNs are the most network- efficient delivery mechanism the only way to make sure data traverse a link only oncethe only way to make sure data traverse a link only once However, US equipment vendors do not provide cache support for fear of lawsuits However, US equipment vendors do not provide cache support for fear of lawsuits  Are P2Ps only useful for violating copyright?

4. P2P for Legal Content Inherent advantages of P2P over CDNs Inherent advantages of P2P over CDNs No high initial costsNo high initial costs No cache installations for ISPs No cache installations for ISPs Practically zero cost for content providers Practically zero cost for content providers Supply grows linearly with demandSupply grows linearly with demand End-host driven application-level routingEnd-host driven application-level routing Many legal content providers want to use P2P Many legal content providers want to use P2P Warner Brothers, Apple iTunes (rumored)Warner Brothers, Apple iTunes (rumored)

5. Challenges for Legal-Content P2Ps User demand for QoS = Cost of content to end user User demand for QoS = Cost of content to end user Challenges for providing QoS Challenges for providing QoS Research problems:Research problems: QoS on top of heterogeneous and dynamic peers QoS on top of heterogeneous and dynamic peers Provide QoS against DDoS attacks Provide QoS against DDoS attacks Need cooperation from network service providerNeed cooperation from network service provider Research issue: a way for P2P to be traffic- engineered by ISPs Research issue: a way for P2P to be traffic- engineered by ISPs Need a pricing structure Need a pricing structure

6. Predictions Content providers will use peers to reduce their delivery costs Content providers will use peers to reduce their delivery costs as long as the QoS issues are figured out…as long as the QoS issues are figured out… Equipment vendors will cache for legal peers Equipment vendors will cache for legal peers Peers and ISP-based CDNs co-exist and collaboratePeers and ISP-based CDNs co-exist and collaborate Delivery agreements between content providers and Cable/DSL ISPs Delivery agreements between content providers and Cable/DSL ISPs