MOBILE AD HOC NETWORK

1. MOBILE AD HOC NETWORK Presented by Lalit Mohan Padhy EC200113375 AT NIST, BERHAMPUR Under the guidance of Mr N. Srinivasu. 1

2. INTRODUCTION .Since 1970’s wireless network become popular as it enables mobility. • There are currently 2 variations of mobile network • Infrastructured network. • Infrastructure less network. • A mobie adhoc network is a infrastructure less network • allows us to communicate emergency search & rescue • operations. • It is one pf the most vibrant & active “new” fields today is • that of adhoc network 2

3. MANET • Definition:- An ad-hoc mobile network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on a continual basis. • MANETs are self-forming, self-maintained, and self-healing, allowing for extreme network flexibility • A MANET consists of mobile platforms (e.g., a router with multiple hosts and wireless communications devices) known as"nodes"--which are free to move about arbitrarily. 3

4. ARCHITECTURE OF MANET • It differs from traditional centralized wireless network as MANET has • No centralized control. • Nodes itself has to provide routing and MAC layers functions. 4

5. CHARACTERISTICS OF MANETS • Dynamic topologies. • Bandwidth-constrained, variable capacity links. • Energy-constrained operation. • Limited physical security. • IP-Layer Mobile Routing . • MANET Routing Protocol Performance Issues. 5

6. MANET ROUTING PROTOCOLS • The following is a list of quantitative metrics that can be used to assess the performance of any routing protocol. • End-to-end data throughput and delay. • Route Acquisition Time. • Efficiency. • Factors affecting efficiency of a protocol: • Average number of data bits transmitted/data bit delivered. • Average number of control bits transmitted/data bit delivered 6

7. PERFORMANCE MEASURE OF MANET PROTOCOL • The following factors measure the performance of a protocol. • Network size. • Topological rate of change. • Link capacity. • Fraction of unidirectional links. • Network connectivity. • Traffic patterns. • Mobility. • Fraction and frequency of sleeping nodes. 7

8. DESIRABLE QUALITATIVE PROPERTIES OF MANET ROUTING PROTOCOLS. • The desirable qualitative properties of MANET routing protocols are given below. • Distributed operation. •   Loop-freedom. • Demand-based operation. • Security. • "Sleep" period operation. • Unidirectional link support. 8

9. CATEGORIZATION OF AD-HOC ROUTING PROTOCOLS 9

10. DESTINATION-SEQUENCED DISTANCE- VECTOR ROUTING (DSDV) • Here Every mobile node in the network maintains a routing table. • Table contains:- • All of the possible destinations within the network. • The number of hops to each destination are recorded. • Each entry is marked with a sequence number assigned by the destination node. • Update table can be sent in 2 ways • Full dump. • Incremental update. 10

11. CLUSTERHEAD GATEWAY SWITCH ROUTING(CGSR) 11

12. THE WIRELESS ROUTING PROTOCOL (WRP) • The Wireless Routing Protocol (WRP) is a table-based protocol with the goal of maintaining routing information among all nodes in the network. • Each node in the network is responsible for maintaining four tables: • Routing table. • Link-cost table. • Message retransmission list (MRL) table. • Distance table 12

13. ADHOC ON-DEMAND DISTANCE VECTOR ROUTING 13

14. DYNAMIC SOURCE ROUTING (DSR) The protocol consists of two major phases: • Route discovery and • Route maintenance 14

15. TEMPORALLY-ORDERED ROUTING ALGORITHM Fig (a) Foot creation (showing link direction assignment) (b)Route maintance (showing link reversal phenomenon) in TORA. 15

16. ASSOCIATIVITY-BASED ROUTING (ABR) Fig-Route Maintenance for Source and Destination Movement in ABR. 16

17. SIGNAL STABILITY ROUTING (SSR) • SSR selects routes based on the signal strength between nodes and on a node's location stability. • This route selection criteria has the effect of choosing routes that have “stronger" connectivities. • SSR can be divided into two cooperative protocols: • Dynamic Routing Protocol (DRP) and • Static Routing Protocol (SRP). • The DRP is responsible for the maintenance of the Signal Stability Table (SST) and the Routing Table (RT). • The SRP processes packets by looking up the destination in the RT and then forwards the packet. 17

18.  PARAMETER DSDV CGSR WRP Time Complexity (link addition / failure) O(d) O(d) O(h) Communication Complexity (link addition / failure) O(x=N) O(x=N) O(x=N) Routing Philosophy Flat Hierarchical Flat Loop Free Yes Yes Yes, but not instantaneous Multicast Capability No No No Number of Required Tables Two Two Four Frequency of Update Transmissions Periodically& as needed Periodically Periodically& as needed Updates Transmitted to Neighbors Neighbors& cluster head Neighbors Utilizes Sequence Numbers Yes Yes Yes Utilizes “Hello” Messages Yes No Yes Critical Nodes No Yes (cluster head) No Routing Metric Shortest Path Shortest Path Shortest Path COMPARISON OF TABLE-DRIVEN PROTOCOLS 18

19. Performance Parameters AODV   DSR TORA  ABR  SSR Time Complexity (initialization) O(2d) O(2d) O(2d) O(d+z) O(d+z) Time Complexity (post failure) O(2d) O(2d) or 0(cache hit) O(2d) O(l+z) O(l+z) Communication Complexity (initialization) O(2N) O(2N) O(2N) O(N+y) O(N+y) Communication Complexity (post failure) O(2N) O(2N) O(2x) O(x+y) O(x+y) Routing Philosophy Flat Flat Flat Flat Flat Loop Free Yes Yes Yes Yes Yes Multicast Capability Yes No No No No Beaconing Requirements No No No Yes Yes Multiple Route Possibilities No Yes Yes No No Routes Maintained in route table route table route table route table route table Utilizes Route Cache/Table Expiration Timers Yes No No No No Route Reconfiguration Methodology Erase Route; Notify Source Erase Route; Notify Source Link Reversal Route Repair Localized Broadcast Query Erase Route; Notify Source Routing Metric Freshest & Shortest Path Shortest Path Shortest Path Associativity & Shortest Path & others Associativity & Stability COMPARISONS OF THE SOURCE-INITIATED ON-DEMAND AD-HOC ROUTING PROTOCOLS. 19

20. Parameters On-Demand Table-Driven Availability of Routing Information Available when needed Always available regardless of need Routing Philosophy Flat Mostly flat except for CSGR Periodic route updates Not required Yes Coping with mobility Using localized route discovery as in ABR and SSR Inform other nodes to achieve consistent routing table Signaling traffic generated Grows with increasing mobility of active routes (as in ABR) Greater than that of on-demand routing. Quality of Service Support Few can support QoS Mainly Shortest Path as QoS metric TABLE-DRIVEN VS ON-DEMAND ROUTING 20

21. CONCLUSION wireless networks can be deployed in either infrastructure-based mode or on an ad-hoc basis. Although work is being done and prototype protocols are available for experiments, mobile ad-hoc networks still have difficulties. While some basic network control functions and routing procedures have been developed, many other issues require attention. Rapidly changing topology, network partitions, higher error rates, collision interference, bandwidth constraints, and power limitations together pose new challenges in network control; especially in the design of higher level Protocols for routing and in implementing applications with quality of service requirements. 21

22. THANK U !!!