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SAP: Storage Aware Protocols For heterogeneous networks. Shweta Jain Assistant Professor Mathematics and Computer Science York College CUNY. Outline. Background and Motivation Overview of network architectures --Applications, Goals , Challenges and Proposed solutions
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SAP: Storage Aware Protocols For heterogeneous networks Shweta Jain Assistant Professor Mathematics and Computer Science York College CUNY
Outline • Background and Motivation • Overview of network architectures • --Applications, Goals , Challenges and Proposed solutions • Seamless communication • Work in progress • Next steps and future directions
Arpanet in 1977 Source: The Computer History Museum ([1]), en:File:Arpnet-map-march-1977.png
Internet in 2010 Source: www.Caida.org
Some Statistics • Mobile broadband users worldwide • 1.2 billion estimated by the ITU in 2011 • Growth rate 45% annually over last 4 years • Mobile broadband subscriptions outnumber fixed subscriptions 2:1 • Top Mobile broadband Usage (survey 2010 by Keynote/Adobe) • Media and entertainment • Social networking, (76%) local information (73%), news (68%), music (63%), games (61%), video (56%) • Travel • Maps (81%), Research travel (47%)
Analysis of Usage • Users prefer to be mobile • People want their content NOW • Mostly “Delay Intolerant” usage • Delay tolerant applications – not so much? • Ebooks,. Podcast, etc • Why do anything different with the delay tolerant traffic?
Google Search Trends – Wimbledon, Olympics, Podcastsand Ebooks Wimbeldon Olympics Podcasts eBooks
Analysis of Usage • Users prefer to be mobile • People want their content NOW • Mostly “Delay Intolerant” usage • Delay tolerant applications – not so much • ebooks,. Podcast • Google trend shows searches including the terms ebooks and podcasts • Similar traffic all year round! • Why do anything different with the delay tolerant traffic? • Need to make way for live streaming during the surge! • Historically when a service improves, demand for service also increases and vice-versa
Key Motivation • Internet has evolved • Needs new protocols for efficient delivery of content • Mobile internet access is highly popular • Need a variety of mobile broadband infrastructures • Mesh and Manet free/low cost services • Sensors, IoT, VANET secure, niche applications for utilities and services • Need protocols that enable seamless communication across these networks • Delay tolerant applications need to be served differently from “delay intolerant” • Podcasts, eBooks, sensors, Internet of Things create traffic all year round
Overview of network architectures Applications, Communication Goals , Communication Challenges and Proposed solutions
Key Features • Routing technique: • Control state or Data state based • Cost metrics: • Link cost or Historical connectivity information • Transport • End-to-end TCP/UDP or Opportunistic transport, send data as soon as a candidate forwarding node is available
Seamless communication Storage aware protocols (Network and Transport)
Key Observations • From an application standpoint: • All networks are in general prone to varying degree of disconnections • Mobile devices lose connectivity for long or short time periods • Mobility triggers new route discovery, causing disconnection until a new end-to-end path is discovered • Sensor networks re-configure routes to avoid network partition due to battery depletion • IoT are struggling with communication storms which may be inferred as disconnection by the application • Cognitive radios stop transmitting when a primary user is detected
Generalized Delay Tolerant Networks: gDTN • Observation: • In general all network architectures have properties similar to the Delay Tolerant Networks • Wireless characteristics • Intermittent connectivity – Cognitive Radio, MANET, VANET • Variable link speed – Bluetooth, WiMAX, WiFi, Cellular Internet • Long term disconnection – Mobility • Every vertical handoff changes the link speed • These are similar to Disruption Tolerant network (DTN) features • DTN is the extreme case of challenged networks • Wired is the other extreme case of well provisioned networks • Other wireless networks are somewhere between this red and green
gDTN: Generalized DTN • ??: • Can a storage and prediction based approach be the one-size fit all solution to the problem of seamless interconnection? • Can we combine features of wireless routing with history and storage based DTN routing? • Proposal • SAP: Storage Aware Protocols for seamless integration of heterogeneous network architectures
Work in progress Storage Aware Protocols (SAP)
Components of SAP • Storage Aware Routing (STAR) • Use history based routing metric • Use storage to delay data delivery while the network searches for “better” paths Better ϵ{Energy efficient, most storage, fastest, higher probability of success,…} • Disruption tolerant transport • End-to-end transport with proxy and feedback for disconnection
STAR: Storage Aware Routing • Compute multiple paths to the destination using the hop count based routing metric- breadth first topology search • Maintain long and short term “expected link rates” to describe the temporal/variable cost component of the routes • Choose to store when the best path is • Worse than usual or • Downstream routers have low available storage (network layer backpressure flow control) • (Future routers will have storage space for caching and temporary storage) (storage is getting cheaper by the year) Forwarding Algorithm
Applicable to all networks? • Applicability: • Long term cost: Time scale of variation depends upon the network type • Storage space: Indicates congestion in wired, wireless, DTN (congestion is a measure of storage space) • Storage aware routing concept for all networks • Unifies and generalizes the routing scheme across networks • Support for mobility • Allows policy and price based store or forward • Avoid expensive 3G • Store if the Wi-Fi data rate is lower than usual
End to End Transport • Send feedback to sender or sender’s agent when data forwarding is interrupted • Sender keeps the route alive by sending 1 byte packets– similar to flow control in TCP • Data is stored at the last router that detected disconnection • If route becomes available, transmission resumes • If it takes too long…. • The end host will need to retry
Next Steps • Implementation and evaluation • Simulation and emulation of network and transport on wired-wireless mesh and DTN testbeds • Tying the lose ends • How much state to maintain? • Proxy placement • How long and how much to store?
Future Directions • Integration of networks is necessary but difficult • Several lose ends and unanswered questions • Security, data integrity and privacy
Thanks for listening! Questions and feedback please?