DTNs Delay Tolerant Networks Papers Fall Kevin Intel Research Berkeley SIGCOMM 2003 Aug25 2003 A DelayTolerant Network Architecture for Challenged Internets August 2003 Warthman Forrest Delay Tolerant Networks DTNs A Tutorial March 2003 Jones Evan P C Practical Routing in DelayTolerant Networks Introduction TCP IP service model works great with connected reliable networks Several implicit assumptions E2E Path exists Connected RTT small Drop probability is small Symmetric Data Rates The TCP IP Model The TCP IP Model Challenged Networks Terrestrial Mobile Networks Exotic Media Networks Military Ad Hoc Networks Sensor Networks Terrestrial Mobile Network Example Challenged Networks Path and Link Characteristics High Latency Low Data Rate Disconnection Long Queuing Times Challenged Networks End System Characteristics Limited Longevity Low Duty Cycle Operation Limited Resources Ideas Fix TCP IP Link Repair Approach Performance Enhancing Proxy PEP Protocol Boosters Proxies Electronic Mail US Postal Service Message Based Overlay Architecture Bundling Store and Forward Nodes use persistent storage to store messages indefinitely Forward when able to do so Otherwise wait DTN DTN Regions A DTN is a network of networks These sub networks are called Regions Each Region has a unique Region ID that is globally known throughout the DTN DTN Resources are identified by name tuples Region ID Entity ID DTN Gateways are members of two or more regions and handles all communication between regions Overlay The Bundle Layer Overlay The Bundle Layer DTN Nodes Custody Transfers Hosts store bundles in persistent storage until custody can be passed or TTL expires Hosts request custody transfer to next hop node Next hop node has option to accept custody Local copy removed upon transfer of custody Only nodes supporting CT can accept custody Transport Layer protocol terminates upon acceptance of custody Custody Transfers Overlay The Bundle Layer DTN Gateway DTN vs TCP IP Names and Addresses Security IPN InterPlanetary Network Example IPN InterPlanetary Network Example Step 1 Bundle Creation at Source IPN InterPlanetary Network Example Step 2 Transmission by Source IPN InterPlanetary Network Example Step 3 First Hop Bundle Processing Forwarding IPN InterPlanetary Network Example Step 4 Second Hop Bundle Processing Forwarding IPN InterPlanetary Network Example Step 5 Bundle Reception at Destination THE END Questions
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