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Challenges of Routing in Ad-hoc Networks. Chandra D Yarlagadda. Ad-hoc Networks. No infrastructure Wireless Node acts as router Used in meetings, emergency situations No home agent or foreign agent. Distance vector routing Distance in hops Periodic broadcasts Router sends to next hop
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Challenges of Routing in Ad-hoc Networks Chandra D Yarlagadda
Ad-hoc Networks • No infrastructure • Wireless • Node acts as router • Used in meetings, emergency situations • No home agent or foreign agent
Distance vector routing Distance in hops Periodic broadcasts Router sends to next hop Fast convergence but bandwidth wasted RIP Conventional Routing Solutions • Link State • State of link • Topology of entire network • Periodic updates • Shortest path based on metric • More accurate but much more bandwidth wasted • OSPF
Problems of Using Conventional Routing protocols • Uplink and Downlink • Link Redundancy • Routing updates • Nature of routers
New Approach • Route Discovery • Simple Method is ARP • Flooding • Transmissions are broadcast • Id’s for duplicate packets • Caching of routes for future use
New Approach • Route Maintenance • Use of Caching prevents nodes to know change of state • Deals with accuracy of the route • Hop by Hop acknowledgement • Bit in the packet to request acknowledgement
Types of Ad-Hoc routing protocols • Table Driven • Source Initiated
Table Driven • Maintain up-to-date information from one node to all other nodes • Information stored in tables • Updates are used to maintain the tables • Differ from conventional routing protocols on the basis of tables maintained and updates sent
Destination-Sequenced Distance-Vector Routing (DSDV) • Every node contains a table containing all other nodes and the hops required • Sequence numbers to maintain new routes • Periodic updates are required • Network traffic is decreased by Full Dump & Incremental packets • Loop Free network • Settling Time
Wireless Routing Protocol • Distance Table • Routing Table • Link-Cost Table • Message Re-transmission List Table
Source-Initiated On-Demand Routing • Source starts a discovery process • Path found only when required • Multiple paths are found • Paths maintained till node is active or is accessible