Abhishek presentation october 2013

744 views
642 views

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
744
On SlideShare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
17
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Abhishek presentation october 2013

  1. 1. BITS Pilani Hyderabad Campus A Survey of Social Based Routing in Delay Tolerant Networks: Positive and Negative Social Effects Abhishek Thakur CSIS, BITS-Pilani, Hyderabad Campus
  2. 2. 10/12/2013 Slide 2 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus For links that are intermittent or poor in quality, end-to-end connectivity and routing may not be guaranteed especially in Extreme Scenario. Limits of MANets and Connected Networks Prob success (iid fail prob pf) over k links: For E2E delivery must have all links up But, expected # of failed links is k fsfs pkppp )1()(;1 fkp
  3. 3. 10/12/2013 Slide 3 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Probability of Delivery
  4. 4. 10/12/2013 Slide 4 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Optimizations on classic ad-hoc and delay-tolerant networking algorithms and began to examine factors such as security, reliability, verifiability – Node mobility would be exploited to help deliver message (mobility-assisted or store-carry- and-forward) Delay-Tolerant Networking Architecture – http://tools.ietf.org/html/rfc4838 Bundle Protocol Specification – http://tools.ietf.org/html/rfc5050 Why? What?
  5. 5. 10/12/2013 Slide 5 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Deep Space Communications – Beyond near-earth – Landers, Orbiters, Deep Space Probes Sensor Networks – Terrestrial: Ocean or Land Based – Extra-terrestrial objects (on planets, etc) High-Stress Physical Environments – Battlefield, Civil Emergency, Submarines This and next few slides – ref Kevin Fall - 2008 What is Extreme?
  6. 6. 10/12/2013 Slide 6 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus • Large Delays • Intermittent and Scheduled Links • Bandwidth Asymmetry • Limited Power • Limited Emission Requirements (LPI/LPD) • Heterogeneous Network Architectures • Link Security Needs • Very Large Scale (e.g. sensor nets) Communications Challenges
  7. 7. 10/12/2013 Slide 7 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Unusual Devices
  8. 8. 10/12/2013 Slide 8 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Extreme systems • Do not (won’t) run IP – High overhead, for global routing – Intra-Oceans: investigate routing – Space: very limited routing [e.g. rover to lander] – Sensors: novel or simple routing, low power • Domain-specific features: – Naming, delivery abstraction, QoS But we don’t want to scrap existing (Internet) software and experience Heterogeneous Architectures The NASA Deep Space Network (DSN) – 3 70m-antenna array [USA, Spain, Australia] Underwater Acoustic Modems – Bottom-to-top comm under 20kbps to 6Km Low-Power CMOS Radios – Conventional and (hopefully) UWB SINGCARS and EPLRS Military Radios
  9. 9. 10/12/2013 Slide 9 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Goals of the DTN architecture: – Interoperability across network architectures – Reliability robust to link and node failure Components: – Reliable Message Overlay with Routing – Interoperability Gateways – Flexible Naming Scheme – Per-hop Authentication with CoS Delay-Tolerant Network Architecture
  10. 10. 10/12/2013 Slide 10 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus End-to-End Message Service: “Bundles” – “postal-like” delivery over regional transports – Optional class of service/notification Key Idea: Custody Transfer – Custodian owns reliable-delivery guarantee – Bundles transferred between custodians toward destination – Sender may free resources upon successful custody transfer Reliable Message Overlay
  11. 11. 10/12/2013 Slide 11 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus “Classic” Concepts (Internet): – Routing: selecting best next hop for every possible destination – Forwarding: sending packet to best next hop • Typically, “on demand” [statistical multiplexing] • Forwarders know a-priori next hop for every destination DTN Concepts: – Routing: selecting best DTN next hop for destination – Forwarding: sending a bundle p2p when possible – Custody Transfer: reliable intra-DTN delivery (with storage) Routing, Forwarding and Custody Transfer
  12. 12. 10/12/2013 Slide 12 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Bundle Routing Example A B B Intermittent Links DS B B B End-to-end Acknowledgement (Sent using bundles, path omitted for clarity) Contact Schedule Aircraft HUMMV Schedule Aircraft HUMMV
  13. 13. 10/12/2013 Slide 13 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Is it possible that data can be delivered? – path between a source and a destination maybe always won’t exist Solution – Traditional protocols: Internet (RIP, OSPF); Ad hoc (DSR, AODV) would fail – Formerly, mobility viewed as evil; Now, it’s perfect – Node mobility would be exploited to help deliver message (mobility-assisted or store-carry-and-forward) Mobility-assisted routing
  14. 14. 10/12/2013 Slide 14 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Two categories – auxiliary nodes assisted (ANA) routing • a set of special auxiliary nodes needed to assist data delivery • VANETs etc. • Throw-boxes / Ferry / Courier nodes / Autonomous Agents … – independent mobile nodes (IMN) routing • there is no additional participants in the deployment area • message delivery achieved by node’s inherent movement • Proactive & reactive • Flooding vs. Heuristics based Overview of Routing schemes
  15. 15. 10/12/2013 Slide 15 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Pure Flooding Probabilistic Flooding Utility Based Flooding – goes into Heuristics Multiple copies get created; Delivery reports used to clean them up Epidemic: Flooding-based
  16. 16. 10/12/2013 Slide 16 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus tX(Y): time since X last saw Y Indirect location information  diffused with node mobility smaller timer closer distance  For most mobility models Utility-based Routing A D B tB(D) = 100 t(D) = 0 t(D) = 26 t(D) = 68 tA(D) = 138 t(D) = 218 Last encounter timers D D Utility UX(Y) = f(tX(Y)) Policy: forward to B if UB(D) > UA(D) + Uth (A. Lindgren et al. ‘03)
  17. 17. 10/12/2013 Slide 17 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Other knowledge-based routing – MaxProp: A variation of Dijkstra’s algorithm • Link weight: an estimate of delivery likelihood between two nodes – MobySpace: each node maintains a high-dimension Euclidean space • Euclidean space: to describe mobility pattern of each node • Encounter occurred: handover message only if the encountered node has more similar mobility pattern with the destination.
  18. 18. 10/12/2013 Slide 18 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Performance metric – Message delivery ratio • The fraction of generated messages that are correctly delivered to the final destination within a given time period – Transmission delay • The time from a message is generated through it is received by destination – Number of transmissions (copies) • The number of message exchange occurred between two nodes Routing objective
  19. 19. 10/12/2013 Slide 19 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus The performance of 2-hop scheme is close enough to multi-hop scheme (Burns et al, ’05) Spray and wait scheme – 2-hop relay scheme • “Spray” a number of copies to the network, then “wait” until one of relay nodes meets the desination – Limited number of copies to L • Multi-path diversity to reduce delay • Achieves O(1) per node capacity 2-hop relay (multiple copies)
  20. 20. 10/12/2013 Slide 20 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus source starts with L copies whenever a node with L > 1 copies finds a new node, it hands over half of the copies (L/2) that it carries; Until L = 1 Binary Tree-based Spraying Src C B Dst D E F D D D DL = 4 L = 2 L = 2 L = 1 L = 1 L = 1 L = 1
  21. 21. 10/12/2013 Slide 21 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Routing issue in DTN is challenge, attracting more attention Category of routing scheme Have good scalability of DTN by exploring node mobility Future direction: develop more realistic networks; from military to public application – Vehicle-based networks – Pocket-switched networks – Social networks – Wildlife tracking networks Summary ANA scheme IMN scheme Knowledge-basedFlooding-based Routing schemes
  22. 22. 10/12/2013 Slide 22 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus • DTN Intro • Node Mobility vs. User’s Social Relations and Behavior • Positive Social Characteristics • Negative Social Characteristics Brief Information From Paper
  23. 23. 10/12/2013 Slide 23 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Community Detection • Modularity, Network of Communities Information Propagation • Spread factor, Spreading Time • Connection Density, Influencing Factor, Critical Nodes Recommendation System(s) • Online shopping / reviews, Twitter / RSS ranking etc. Security and Privacy • Anti-Spam, limitations of blacklists, multiparty Authorization. • Privacy / Anonymity and re-identification algo for anonymized social network Social Network Analysis
  24. 24. 10/12/2013 Slide 24 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Custody Transfers tied to contact graphs and duration of contact Communality, Centrality and Similarity of nodes Time slot based graph vs. Each edge records number, time and period of encounters Contact graphs for DTN nodes and Social graphs for owners are loosely identical. Question: How do the encounter tables get shared on large DTNs? Possibly scope to research further. Social property if DTN : Graphs
  25. 25. 10/12/2013 Slide 25 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Since DTN nodes are carried by people, they will tend to mimic communities. {impact of device sharing} Sociological Centrality metrics will imply that such nodes are strong relay nodes • Degree, Betweenness & Closeness to Destination Similarity to Destination User location, Destination User Interests etc. implies that such relay nodes are likely to get near the destination. {challenge other than location how to capture and model similarity – data generated, apps used etc.} Social property if DTN : Community, Centrality, Similarity
  26. 26. 10/12/2013 Slide 26 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Similarity can infer Friendship: Long lasting regular contacts coupled with common interests in real world. Rational Selfish behavior of social nodes implies that they want to send/receive DTN data not act as relay’s for other’s data … Friendship and Selfishness
  27. 27. 10/12/2013 Slide 27 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Label Routing Hui & CrowCroft – Pocket Switched nodes – IEEE PerCom 2007 • Community included as part of label • Nodes also share their affiliations and Groups i.e. Social communities SimBet Routing Daly and Haar (ACM Symposium … 2007) • Explores bridge nodes using betweenness, centrality and similarity. • Using Betweenness and Similarity to destination, the Utility of node as next hop can be evaluated • Scales by estimating centrality using only locally visible information – but can have –ve effects Approaches used for Benefiting from Social Characteristics
  28. 28. 10/12/2013 Slide 28 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Bubble Rap Forwarding Hui & other (MobiHoc 2008) • Community and centrality • Fast transfer towards destination community – bubble up towards global centrality and bubble within community • Changeless to in Hierarchical communities or for communities on periphery (non-central) Social Multicasting Gao & others (MobiHoc 2009) • Centrality metric and community metric for relay • Single data or multi-data multicast • For Single data, assumed uniform destination distribution • For Muti-data – use gateway nodes for multiple communities Approaches used for Benefiting from Social Characteristics…
  29. 29. 10/12/2013 Slide 29 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Homophily Based data diffusion Zang & others (MobiHoc 2009) • Prioritizes data propagation order (contact duration / storage space limited) • Homophily => shared interest {challenge to identify / model this} • Share most similar data items between friends and most different Data Items between strangers Social Multicasting Bulut & others (GLOBECOM 2010) • Social Pressure Metric [weighted by frequent long lasting regular contacts] • Data sharing / storage complexity is high User Centric Disseminataion Gao & Cao (INFOCOMM 2011) Approaches used for Benefiting from Social Characteristics…
  30. 30. 10/12/2013 Slide 30 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Questions ? Thanks
  31. 31. 10/12/2013 Slide 31 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus Backup
  32. 32. 10/12/2013 Slide 32 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus http://www.dtnrg.org http://irtf.org/dtnrg http://www.nasa.gov/mission_pages/station/research/experimen ts/DTN.html – Disruption Tolerant Networking Slide references – http://bwrc.eecs.berkeley.edu/php/pubs/pubs.php/762/Delay%20Tolerant%20Architectur e%20v1%20Kevin%20Fall.ppt – http://www.networks.howard.edu/hguo/docs/prest05.ppt – http://netlab.cs.ucla.edu/wiki/files/relaycast_icnp08_final.ppt Additional References
  33. 33. 10/12/2013 Slide 33 NetClique.in Internal Presentations BITS Pilani, Hyderabad Campus • Bundle, Payload, Fragment • Bundle node • Bundle protocol agent • Convergence layer adapters • Application agent • Bundle endpoint • Forwarding, Registration, Delivery • Deliverability/Abandonment • Deletion, Discard • Transmission • Custody Terminology

×