Mobile ad hoc network protocols ppt

mobile ad hoc networks ppt slides and multicast routing protocols for mobile ad-hoc networks ppt and applications of mobile ad hoc networks ppt
JaydenGibbs Profile Pic
JaydenGibbs,United States,Teacher
Published Date:19-07-2017
Your Website URL(Optional)
MOBILE ADHOC NETWORKS (MANETs): An Introduction Dr. A K Verma Department of Computer Science and Engineering Thapar University PatialaAN OVERVIEW  Wireless Networks  MANET (Defn. , applications)  Routing (Defn. , Types) Routing Protocols in MANET - Proactive (6) - Reactive (5) - Hybrid (1)Wireless Networks Need: Access computing and communication services, on the move  Infrastructure-based Networks –traditional cellular systems (base station infrastructure)  Wireless LANs – Infrared (IrDA) or radio links (Wavelan) –very flexible within the reception area; ad-hoc networks possible –low bandwidth compared to wired networks (1-10 Mbit/s)  Ad hoc Networks –useful when infrastructure not available, impractical, or expensive –military applications, rescue, home networkingCellular Wireless Single hop wireless connectivity to the wired world –Space divided into cells –A base station is responsible to communicate with hosts in its cell –Mobile hosts can change cells while communicating –Hand-off occurs when a mobile host starts communicating via a new base stationMulti-Hop Wireless  May need to traverse multiple links to reach destination  Mobility causes route changesMobile Ad hoc Networks (MANETs)  Host movement frequent  Topology change frequent B A A B  No cellular infrastructure. Multi-hop wireless links  Data must be routed via intermediate nodesWHY ADHOC NETWORKS?  Setting up of fixed access points and backbone infrastructure is not always viable - Infrastructure may not be present in a disaster area or war zone - Infrastructure may not be practical for short-range radios; Bluetooth (range 10m) Ad hoc networks: -Do not need backbone infrastructure support - Are easy to deploy - Useful when infrastructure is absent, destroyed or impracticalApplications of MANET  Personal area networking –cell phone, laptop, ear phone, wrist watch  Military environments –soldiers, tanks, planes  Civilian environments –taxi cab network –meeting rooms –sports stadiums –boats, small aircraft  Emergency operations –search-and-rescue –policing and fire fightingChallenges in Mobile Environments  Limitations of the Wireless Network packet loss due to transmission errors variable capacity links frequent disconnections/partitions limited communication bandwidth Broadcast nature of the communications  Limitations Imposed by Mobility dynamically changing topologies/routes lack of mobility awareness by system/applications  Limitations of the Mobile Computer short battery lifetime limited capacitiesRouting in MANETs Challenges for Routing Protocols No centralized entity Host is no longer just an end system Acting as an intermediate system Changing network topology over time Every node can be mobileEffect of mobility on the protocol stack  Application –new applications and adaptations  Transport –congestion and flow control  Network –addressing and routing  Link –media access and handoff  Physical –transmission errors and interferenceROUTING ? • Network with nodes, edges • Goal: Devise scheme for transferring message from one node to another. –Which path? –Who decides – source or intermediate nodes? msgWHICH PATH?  Generally try to optimize something: –Shortest path (fewest hops) –Shortest time (lowest latency) –Shortest weighted path (utilize available bandwidth) –Etc.Routing ? Ants Searching for Food ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Example: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 placeWho determines route? 2 General Approaches:  Source (“path”) routing Source specifies entire route: places complete path to destination in message header: A – D – F – G Intermediate nodes just forward to specified next hop: D would look at path in header, forward to F Like airline travel – get complete set of tickets to final destination before departing…Who determines route? …..contd.  Destination (“hop-by-hop”) routing –Source specifies only destination in message header: G –Intermediate nodes look at destination in header, consult internal tables to determine appropriate next hop –Like postal service – specify only the final destination on an envelope, and intermediate post offices select where to forward next…Comparison •Destination routing  Source routing - No source storage –Moderate source storage (entire route for - High intermediate node each desired dest.) storage (table w/ routing instructions for all possible –No intermediate node dests.) storage - Lower routing overhead –Higher routing (just dest in header, only overhead (entire path in routers need deal w/ route message header, route discovery) discovery messages)AD HOC ROUTING  Every node participates in routing: no distinction between “routers” and “end nodes” •No external network setup: “self-configuring” •Especially useful when network topology is dynamic (frequent network changes – links break, nodes come and go)