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Presentation on theme: "Routing protocols in Mobile Ad Hoc Network UNIVERSITY COLLEGE OF ENGINEERING BURLA, SAMBALPUR."— Presentation transcript:


2 Types of Wireless Networks Infrastructure based(Cellular Network). Infrastructureless Network(Mobile Ad hoc NETwork) (MANET).

3 Characteristics of an Ad-hoc network Collection of mobile nodes forming a temporary network Network topology changes frequently and unpredictably No centralized administration or standard support services Host is also function as router

4 Why is Routing Different in Ad Hoc ??? Host mobility Dynamic topology link failure/repair due to mobility Distributed Environment Bandwidth constrained Energy constrained

5 Categorization of Ad-Hoc Routing Protocols

6 Table Driven Routing Protocol Proactive. Each node maintains one or more tables containing routing information to every other node in the network. Tables need to be consistent and up-to-date view of the network. Updates propagate through the network

7 Source Initiated On demand routing protocol Reactive. on-demand style: create routes only when it is desired by the source node When a node requires a route to a destination, it initiates a route discovery process Route is maintained until destination becomes unreachable, or source no longer is interested in destination.

8 Table Driven Routing Protocol

9 Destination-Sequenced Distance Vector Protocol (DSDV) Basic Routing Protocol Based on Bellman ford routing algorithm with some improvement Each node maintains a list of all destinations and number of hops to each destination. Each entry is marked with a sequence number. Periodically send table to all neighbors to maintain topology Two ways to update neighbors: –Full dump –Incremental update

10 Example of DSDV DestinationNext HopDistanceSequence Number AA0S205_A BB1S334_B CC1S198_C DD1S567_D ED2S767_E FD2S45_F DestinationNext HopDistanceSequence Number AA0S304_A BD3S424_B CC1S297_C DD1S687_D ED2S868_E FD2S164_F As Routing Table Before Change As Routing Table After Change

11 Clusterhead Gateway Switch Routing (CGSR) Similar to DSDV Based on concept of clusters and cluster heads Routing is done via the cluster heads and gateways A routing table among cluster heads are maintained

12 Example of CGSR Data forwarding steps: from cluster head to cluster head –in a hierarchical manner then from cluster head to cluster members between two cluster heads, gateways are used to forward the packets

13 Source Initiated On demand routing protocol

14 Ad hoc On-demand Distance Vector Routing (AODV) Pure on-demand protocol Node does not need to maintain knowledge of another node unless it communicates with it AODV includes route discovery and route maintenance. AODV minimizes the number of broadcasts by creating routes on-demand AODV uses only symmetric links because the route reply packet follows the reverse path of route request packet AODV uses hello messages to know its neighbors and to ensure symmetric links

15 Path discovery In the path discovery (RREQ) phase, source broadcasts RREQ message. Intermediate nodes record in their route tables the address of neighbor from which RREQ is received to establish a reverse path. When RREQ reaches destination or an intermediate node responds by unicasting a route reply (RREP) back to neighbor.

16 Path maintenance If source node moves, reestablish the path. If destination or intermediate node moves, send link failure notification message to each of its active upstream. Then reinitiate path discovery.

17 Dynamic Source Routing Protocol (DSR) on-demand A node maintains route cache containing the routes it knows Two main phases Route discovery Route maintenance Basic Operation is similar to AODV. Main difference To use routing cache for link failure. When route discovery phase, node send route request message with its own address.

18 Example of DSR

19 Hybrid Routing Protocols

20 Zone Routing Protocol Hybrid of table-driven and on-demand!! From each node, there is a concept of zone. Within each zone, the routing is performed in a table-driven manner (proactive). However, a node does not try to keep global routing information. For inter-zone routing, on-demand routing is used.

21 Example of ZPR Three types of nodes: Border Nodes Peripherals Nodes Interior Nodes

22 Comparison Parameters On DemandTable Driven Availability of routing information Available when needed Always available regardless of need Routing philosophyFlat Mostly flat, except for CGSR Periodic route updatesNot requiredRequired Coping with mobilityUse localized route discovery Inform other nodes to achie ve a consistent routing table Signaling traffic generatedGrows with increasing mobility Greater than that of on demand routing

23 References Elizabeth M. Royer, Chai-Keong Toh, A Review of Current Routing Pro tocols for Ad Hoc Mobile Wireless Networks,Proc. IEEE,1999. David B. Johnson, " Routing in Ad hoc Networks of Mobile Hosts", Proc IEEE Workshop on Mobile Computing Systems and Applications. Nicklas Beijar Zone Routing Protocol. issues/issue200407/ html


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