Size Scale Matters: Challenged Networks Everywhere?! · PDF file 1 Size Scale Matters:...

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Transcript of Size Scale Matters: Challenged Networks Everywhere?! · PDF file 1 Size Scale Matters:...

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    Size Scale Matters: Challenged Networks Everywhere?!

    Jörg Ott

    Technische Universität München

    www.cm.in.tum.de

    CHANTS Workshop

    ACM MobiCom 2017

    20 October 2017

  • 2© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    CHANTS Landscape WDTN / CHANTS

    AOC

    MobiOpp

    ExtremeCom

    D TN

    R G

    D TN

    W G

    Dagstuhl

    2017

    2015

    2010

    2005

    2000

    C C

    SD S

    SIGCOMM, MobiCom, MobiHoc, MobiSys, … INFOCOM, WoWMoM, PerCom, SECON, …

    1998 (IPN)

    2003

    2013

  • 3© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Challenged Networks haven’t disappeared

    (well, maybe some of the esoteric cases are now called ICN J)

    they are just becoming more mainstream now

    and often appear at different scales

  • • Flashback

    • Scaling dimensions

    • Case studies: Classical challenged networks

    • When networks become challenged

    • Perspectives

    4© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Roadmap

  • 5© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Flashback

    SystemsApplications

    Themes

    Topics

  • 6© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Flashback

    SystemsApplications

    Themes

    Topics

    • Inter-planetary networking • Military networking • Maritime communications (AUVs, buoys, …) • Vehicular and UAV/drone ad-hoc networks • Sensor networks • Emergency and disaster communication • Networking for developing regions • Social opportunistic networking • Community and DIY networks

  • 7© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Flashback

    SystemsApplications

    Themes

    Topics

    • Micro blogging, twitter, e-mail • Web access and video streaming • Chat, blackboard, walkie-talkie, image sharing • Music (and video) sharing • Opportunistic Social Networks:

    Safebook, D-Book, fbDTN • Distributing (multimedia) (education) content • Entertainment in crowds • Wildlife, environmental, and geo monitoring

    (read: challenged IoT) • Medical monitoring, medical support

  • 8© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Flashback

    SystemsApplications

    Themes

    Topics

    • Generic platforms • ION • DTN2 • IBR-DTN • SCAMPI + liberouter • k x Haggle • NetInf

    • Integrated applications • Twimight • PodNet • Opphos • PirateBox & similar

  • 9© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Flashback

    SystemsApplications

    Themes Mobility data collection and analytics, mobility modeling – Message forwarding, scheduling, dropping, fragmentation – System and performance modeling – Message Ferrying and data mules – Routing^n – Network and source coding – Content distribution, content caching – MANET and IP-related topics – Efficient neighbor discovery – simulators – Implementation and performance evaluation – Convergence layers – Multi-contact encounters in dense networks – Mutex mechanisms, state synchronization – Security and Privacy – Context awareness – Social networking and communities; modeling, analysis, and exploitation – Data centric networks – Leveraging different radios – integrating cellular and Wi- Fi: Mobile offloading – Energy efficiency and power management – Incentive mechanisms – Resource awareness and management – Congestion control – Crowd computing – Sensor networks and crowd sourcing – Network and device monitoring and management – Time protocols – New flavors of transport or session protocols – (Centralized) control (channels) for content distribution – applications

    Topics

  • • From theory to practice

    • Sensor networks and applications

    • Low energy systems

    • Disaster scenarios and remote areas

    • Internet-independent networks and applications

    • Content sharing in different ways (point-to-point messaging disappearing)

    10© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Some trends

  • • Flashback

    • Scaling dimensions

    • Case studies: Classical challenged networks

    • When networks become challenged

    • Perspectives

    11© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Roadmap

  • (Selected) Scaling dimensions

    © 2017 Jörg Ott | Chair of Connected Mobility | TUM 12

    Node density

    (Path) latency

    Message size

    Link performanceNetwork reach

    Network size

    Node / network dynamics

    Connectivity

  • • Defines: node degree/connectivity and interference • Implications: reachability, routing and resource management

    • From energy efficient scanning for scarce contact opportunities • To node selection and congestion avoidance

    • Research focus: towards sparse networks • Hybrid and adaptive routing schemes • Special considerations for dense networks

    13© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Node density

    full meshsparse dense

  • • Defines: network stability • Implications: contact characteristics, node mixing

    • Efficiency requirements for node discovery and data exchange • Routing algorithms and their optimization goals (e.g. spread vs. utility)

    • Research focus: scenarios with at least partial motion • Fastest ones are probably the satellite ring road

    14© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Node / network dynamics

    stationary fast movingmovingpartly moving

  • 15© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Connectivity (Kevin Almeroth, CHANTS 2007)

    Continuous connectivity

    • Defines: availability of access to a network backbone • Also: connectivity among a set of nodes

    • Example: duty cycling – always-on vs. sleepy sensor nodes

    • Implications: instant reach and synchronization • Latency, “wormholes” through the backbone • Forwarding vs. carrying • Nature of the system and protocol design

    • Research focus: usually mostly disconnected • From autonomous operation to intermittent (dis)connectivity

    Intermittent disconnectivity

    Intermittent connectivity

    Infrequent connectivity

    Autonomous operation

  • 16© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Link / path latency (+predictability)

    ns weeks

    • Defines: delivery delay (and control loop latency) • Implications: potential for interactivity and protocol design

    • also a function of delivery reliability • from transaction-based protocols to self-contained messaging

    • Research focus: tens of seconds to few days • Deterministic as in planetary and satellite schedules • Opportunistic as in pocket-switched networks

    hours dayssecs mins

  • 17© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Link performance

    bits/min Gb/s

    • Considers bit error rate: effective data rate

    • Defines: link and path capacity • Implications: delivery efficiency and protocol overhead

    • Time needed to get something useful done • Feasibility of redundancy

    • Research focus: kbit/s to Mbit/s • From sensor networks and low power nodes to WLAN-based systems • Hybrids for control vs. data channels

    Mbit/skbits/s

  • 18© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Message size

    Bytes GB

    • Defines: feasible payload size • “What can a single message do.” • Part of a sequence vs. self-contained

    • Implications: system operation and application design • Protocol design and APIs • Acceptable header overhead and per-message operations • Resource management • Transmission scheduling, multiplexing, and fragmentation

    • Research focus: small “packets” to images and videos • From BLE beacons to image sharing to audio/video content delivery

    MBKB

  • 19© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Network size

    2 1010

    • Defines: complexity, potential load, competition • Open vs. closed networks • Limiting to a relevant subset: Geographic area, time window

    • Implications: how much a node can know / do about others • History of node contacts and associated information

    • e.g. for utility computation • Space-time connectivity graph • Resource management (buffer multiplexing, subgrouping, priorities, …) • Trust and security models

    • Research focus: 2 – 103, sometimes 104

    103 106

  • 20© 2017 Jörg Ott | Chair of Connected Mobility | TUM

    Network reach

    Local Global

    • Defines: scope of operation • within vs. across social networks • closed vs. open groups

    • Implications: feasible routing strategies, latency • flooding vs. opportunistic vs. deterministic routing • relayed or not • Also: feasible trust models

    • Research focus: dual • local and neighborhood environments • global and inter-planetary

    Inter-planetaryNeighborhood City …

  • The Internet

    © 2017 Jörg Ott | Chair of C