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Tseng:1 Introduction to Ad Hoc Networking Perkin’s book: Ch 1 and Ch 2. Some data collected from the Internet by Prof. Yu-Chee Tseng.

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Presentation on theme: "Tseng:1 Introduction to Ad Hoc Networking Perkin’s book: Ch 1 and Ch 2. Some data collected from the Internet by Prof. Yu-Chee Tseng."— Presentation transcript:

1 tseng:1 Introduction to Ad Hoc Networking Perkin’s book: Ch 1 and Ch 2. Some data collected from the Internet by Prof. Yu-Chee Tseng

2 tseng:2 Model of Operations

3 tseng:3 Assumptions Symmetric Links:  unidirectional links are difficult to dealt with, and sometimes at the verge of failure Layer-2 Routing:  Most protocols are presented in layer-3 routing, but can be easily retooled as a layer-2 ones. Proactive vs. Reactive Protocols  (to be elaborated later)

4 tseng:4 Applications ad hoc conferencing home networking emergency services personal area network (PAN) ubiquitous computing  “computers are all around us, constantly performing mundane tasks to make our lives a litter easier”  “Ubiquitous intelligent internetworking devices that detect their environment, interact with each other, and respond to changing environmental condition will create a future that is as challenging to imagine as a science fiction scenario.”

5 tseng:5 Sensor Dust:  a large collection of tiny sensor devices  once situated, the sensors remain stationary  largely homogeneous  power is likely to be a scarce resource, which determines the lifetime of the network  can offer detailed information about terrain or environmental dangerous conditions. Intelligent Transportation System:  may be integrated with cars, positioning devices, etc.

6 tseng:6 Technical Factors scalability power budget vs. latency protocol deployment and incompatibility standards  “Unless a miracle happens (e.g., the IETF manet working group is able to promulgate a widely deployed ad hoc networking protocol), ad hoc networks will gain momentum only gradually because users will have to load software or take additional steps to ensure interoperability. wireless data rate  e.g., TCP over multi-hop wireless links security issues

7 tseng:7 More Extensions (DoD’s Perspective) could be a group of hosts supported by one or more radios could across the Internet

8 tseng:8 IEFT MANET Working Group goal:  to standardize an interdomain unicast routing protocol which provides one or more modes of operation, each mode specialized for efficient operation in a given mobile networking “context”, where a context is a predefined set of network characteristics. a dozen candidate routing protocols have been proposed.

9 tseng:9 Applications of Ad Hoc Networks

10 tseng:10 Network Architectures No Infrastructure (ad hoc networks):  no base stations; no fixed network infrastructure

11 tseng:11 MANET MANET = Mobile Ad Hoc Networks  multi-hop communication  needs support of dynamic routing protocols


13 tseng:13 Nokia Rooftop Product

14 tseng:14 Nokia RoofTop RoofTop solution (Nokia, Finland)  Wireless router  a radio frequency (RF) modem  a digital Internet protocol (IP) router

15 tseng:15 FHP FHP Wireless, USA ad hoc network in a campus

16 tseng:16 FHP Wireless

17 tseng:17 FHP Wireless

18 tseng:18 MeshNetworks MeshNetworks, USA

19 tseng:19 System – MeshNetworks Architecture

20 tseng:20 Networking Scenario : To Internet

21 tseng:21 SkyPilot NeighborNet SkyPilot Network, USA

22 tseng:22 Routing = Ants Searching for Food ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

23 tseng:23

24 tseng:24 Three Main Issues in Ants’ Life Route Discovery:  searching for the places with food Packet Forwarding:  delivering foods back home Route Maintenance:  when foods move to new place

25 tseng:25 Proactive vs. Reactive Routing  Proactive Routing Protocol: continuously evaluate the routes attempt to maintain consistent, up-to-date routing information  when a route is needed, one may be ready immediately when the network topology changes  the protocol responds by propagating updates throughout the network to maintain a consistent view  Reactive Routing Protocol:  on-demand  Ex: DSR, AODV


27 tseng:27 DSDV Destination Sequenced Distance Vector  Table-driven  Based on the distributed Bellman-Ford routing algorithm  Each node maintains a routing table  Routing hops to each destination  Sequence number

28 tseng:28 DSDV Problem  A lot of control traffic in the network Solution  two types of route update packets  Full dump All available routing information  Incremental Only information changed since the last full dump

29 tseng:29 Clustering Protocol Cluster Gateway Switch Routing (CGSR)  Table-driven for inter-cluster routing  Uses DSDV for intra-cluster routing C3 M2 C2 C1

30 tseng:30 AODV Ad hoc On-demand Distance Vector  On-demand driven  Nodes that are not on the selected path do not maintain routing information  Route discovery  The source node broadcasts a route request packet (RREQ)  The destination or an intermediate node with “fresh enough” route to the destination replies a route reply packet (RREP)

31 tseng:31 AODV N2 N4 N1 N3 N5 N6 N7 N8 Source Destination N2 N4 N1 N3 N5 N6 N7 N8 Source Destination (a) RREQ (b) RREP

32 tseng:32 AODV Problem  A node along the route moves Solution  Upstream neighbor notices the move  Propagates a link failure notification message to each of its active upstream neighbors  The source node receives the message and re- initiate route discovery

33 tseng:33 DSR Dynamic Source Routing  On-demand driven  Based on the concept of source routing  Required to maintain route caches  Two major phases  Route discovery  Route maintenance A route error packet

34 tseng:34 DSR N2 N4 N1 N3 N5 N6 N7 N8 N1 N1-N2 N1-N3-N4 N1-N3-N4-N7 N1-N3-N4-N6 N1-N3 N1-N3-N4 N1-N2-N5 N2 N4 N1 N3 N5 N6 N7 N8 N1-N2-N5- N8

35 tseng:35 ZRP Zone Routing Protocol  Hybrid protocol  On-demand  Proactive  ZRP has three sub-protocols  Intrazone Routing Protocol (IARP)  Interzone Routing Protocol (IERP)  Bordercast Resolution Protocol (BRP)

36 Zone Radius = r Hops Zone of Node Y Node X Zone of Node X Node Z Zone of Node Z Border Node Bordercasting

37 tseng:37 LAR Location-Aided Routing  Location information via GPS  Shortcoming  GPS availability is not yet worldwide  Position information come with deviation

38 tseng:38 LAR (Xs,Ys) SRC Request ZoneExpected Zone DEST R (Xd+R, Yd+R) (Xd,Yd)

39 tseng:39 DREAM Distance Routing effect Algorithm for mobility  Position-based  Each node  maintains a position database  Regularly floods packets to update the position Temporal resolution Spatial resolution

40 tseng:40 PAR Power-Aware Routing +–+– +–+– +–+– +–+– +–+– +–+– SRC N1 N2 DES T N4 N3

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