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content distribution and “protocol”: from hierarchical trees to distributed graphs. Jason Gaedtke j.gaedtke@cablelabs.com November 7, 2007. abstract.
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content distribution and “protocol”: from hierarchical trees to distributed graphs Jason Gaedtke j.gaedtke@cablelabs.com November 7, 2007
abstract • codec efficiency advances, recording device and storage commoditization, and broadband access network maturity have enabled an explosion in the consumption of professional and user-generated IP video • traditional media distributors and emerging Internet providers are challenged to drive cost from their IP video business models • the P2P architectural paradigm and the philosophical and cultural concept of “Protocol” offer a compelling alternative to traditional, hierarchical CDNs
definition (Galloway, MIT Press 2004) • “protocol” • a system of distributed management/control strategies • facilitates P2P relationships between autonomous entities • anti-hierarchical and anti-authority • engenders localized decision-making, versus centralized • accommodates massive contingency/change • represents the outcome (not the antecedent) of distributed behavior • analysis occurs at the intersection of philosophy, culture and technology • control moves from authorities to protocol standards
philosophical and political considerations • mesh vs. hierarchy • favors horizontal, distributed organization and control • e.g. TCP/IP vs. DNS (hindered by points of control/failure) • end-to-end principal: state/intelligence at the edges • historical movement • centralized (server) -> decentralized (cluster) -> distributed (net) • low barrier-to-entry empowers participation, breeds innovation • a similar decentralized/distributed control model underlies proven and successful open source collaboration • this concept, Protocol, is native to the logical design/architecture of the Internet (TCP/IP) • infrastructure and associated corporate capital investment notwithstanding (i.e., root of present Net Neutrality debate)
business and economic considerations • primary appeal: storage, processing, and bandwidth cost avoidance; >90% savings • application infrastructure is self-organizing/healing; minimal admin/ops overhead • must consider/provide user value-proposition (beyond “free content”) motivating participation and resource contribution • Internet public policy and intellectual property law/enforcement still evolving • growing need for security and data integrity assurances
technical considerations • P2P substrates: • form a decentralized, self-organizing and fault-tolerant overlay network • provide efficient request routing, deterministic object location, and load-balancing in an application-independent manner • facilitate application-specific object replication, caching, and fault recovery • enable robust and efficient data and service availability, reliability and geographical/route diversity and redundancy • offer compelling scaling features and performance typically O(log(N)) • participatory design, development and control model engenders innovation
applications • substantial academic and corporate research over the past five+ years • horizontal, mesh networks and P2P applications evolving beyond file-sharing • music/movies/tv “sharing”: Napster, Gnutella, KaZaA, eDonkey, FreeNet, BitTorrent • voice: Skype, IETF’s P2P SIP • video: Azureus, Joost • storage: OceanStore, Ivy • commercial content distribution: Move, Grid, Pando, Red Swoosh (Akamai), Kontiki (VeriSign) • gaming and virtual worlds: Quazal, FT’s Solipsis • virtual economies: Scrivener (Rice), Tribler (Harvard)
research and references • “Protocol: How Control Exists after Decentralization” • Alex Galloway (NYU) • MIT Press, 2004 • Philosophical foundations in Marx, Foucault, Deleuze, Jameson, Hardt • academic research • Berkeley (OceanStore persistence) • Columbia (P2P SIP audio/video communications) • MIT (Chord DHT, Ivy file-system) • Purdue (Pastry, Dynamic P2P Source Routing) • Rice (FreePastry, Squirrel web cache) • Washington (Pastry, BitTyrant) • corporate R&D • France Telecom (Solipsis virtual world, Maay search engine, • Microsoft (Herald pub/sub, SimPastry, PAST archive, SplitStream CDN) • Distributed Computing Industry Association (DCIA) P4P Working Group • Explicit Communications for Cooperative Control Between P2P and Network Providers • IETF P2P SIP • looking to add CableLabs to this list
enabling technologies • reliable and efficient storage, search and discovery algorithms • DHTs: Chord, CAN, Pastry, Tapestry • identity • reputation • security • virtual economy • quality of service • multicast