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Protocol Support for Lookup Services
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In a mobile ad hoc network (MANET), lookup services can be implemented using either unstructured or structured overlay networks, so called distributed hash tables. Structured overlays assign identifiers to nodes and constrain the identifiers of overlay neighbors and the keys of the objects that they store. They can locate objects efficiently without flooding, for example, lookups can cost O(logN) with O(logN) state per node. However, such approaches put some requirements on the MANET environment: (1) The MANET must provide a high degree of connectivity such that a given node can contact each other node at any time with high probability. (2) The nodes in the MANET must exhibit low mobility in order to minimize the required number of updates of routing tables and other structures. Typically, both structured and unstructured approaches will perform poorly in scenarios with low connectivity and high mobility. However, the mobility intrinsic in MANET can also be exploited to efficiently distribute and locate resources across the network by epidemic dissemination of information.
Most of the research in the area of lookup services for MANET is still in its early stages, so there are numerous challenges:
- Is structure required, and if, how much of it? Do general structured approaches (like DHTs) provide the right abstraction for a large class of MANET applications?
- Can applications that are currently implemented using structured and unstructured overlays be directly used on MANETs?
- How do we evaluate the different approaches for lookup services under realistic environmental parameters and workloads?
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Funding
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German Science Foundation (DFG): April 1, 2004 till December 31, 2008 |
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Publications
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C. Lindemann and O. Waldhorst, Effective Dissemination
of Presence Information in Highly Partitioned Mobile Ad Hoc Networks, Proc.
3rd IEEE Int. Conf. on Sensors, Mesh and Ad Hoc Communications and Networks
(IEEE SECON) , Reston, VA, September 2006 PDF.
C. Lindemann and O. Waldhorst, Modeling Epidemic Information Dissemination
on Mobile Devices with Finite Buffers, Proc. ACM. Int. Conf. on
Measurement & Modeling of Computer Systems (ACM SIGMETRICS 2005),
Banff, Canada, 121-132, June 2005.
PDF
C. Lindemann and O. Waldhorst, Exploiting Epidemic Data Dissemination for Consistent Lookup Operations
in Mobile Applications, ACM Mobile Computing and Communication Review (MC2R) Special Issue on Mobile Data Management, 8, 44-56, 2004. PDF
A. Klemm, C. Lindemann, M. Vernon, and O. Waldhorst, Characterizing the Query
Behavior in Peer-to-Peer File Sharing Systems, Proc. Internet Measurement
Conference (IMC 2004), Taormina, Italy, October 2004. PDF
A. Klemm, C. Lindemann, and O. Waldhorst, A Special-Purpose Peer-to-Peer
File Sharing System for Mobile Ad Hoc Networks, Proc. IEEE Semiannual
Vehicular Technology Conference (VTC2003-Fall), Orlando, FL, October 2003.
PDF
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Dissertations
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"Design and Quantitative Analysis of Protocols for Epidemic Information Dissemination in Mobile Ad Hoc Networks", University of Dortmund, November 2005.
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