CSE 6007 Mobile Ad Hoc Wireless Networks Unit II Topic 8-15 Routing Protocols for Ad Hoc Wireless Networks Department of Computer Science and Engineering Kalasalingam University

Outline Introduction Topic 8 : Issues in Designing A Routing Protocol for Ad Hoc Wireless Networks Topic 9 : Classification of Routing Protocols Topic 10 : Table Driven Routing Protocols Topic 11 : On-Demand Routing Protocols Topic 12 : Hybrid Routing Protocols Topic 13 : Routing Protocols with Efficient Flooding Mechnisms Topic 14 : Hierarchical Routing Protocol Topic 15 : Power Aware Routing Protocol

The main routing problems for MANETs 8 10 9 7 4 6 Node mobility  Routing path broken frequently 2 3 5 1

Traditional ad-hoc routing protocols

Table-driven routing protocol – DSDV (cont.) Example: Routing table for Node 1 15 Dest NextNode Dist seqNo 2 1 22 3 26 4 5 32 134 6 144 7 162 8 170 9 186 10 142 11 176 12 190 13 198 14 214 15 256 14 13 11 12 10 9 8 6 4 7 5 3 1 2

Table-driven routing protocol – DSDV (cont.) Routing table for Node 1 15 Dest NextNode Dist seqNo 2 1 22 3 26 4 5 32 134 6 144 7 162 8 170 9 186 10 142 11 180 12 190 13 198 14 214 15 256 14 13 11 12 10 8 9 6 4 7 5 3 1 2

Route Discovery in DSR Y Z S E F B C M L J A G H D K I N Represents a node that has received RREQ for D from S

Route Discovery in DSR Y Broadcast Z [S] S E F B C M L J A G H D K I N Represents transmission of RREQ [X,Y] Represents route record stored in RREQ

Route Discovery in DSR Y Z S [S,E] E F [S,B] B C M L J A G [S,C] H D K Node H receives packet RREQ from two neighbors: potential for collision

Route Discovery in DSR Y Z S E F B [S,E,F] C M L [S,B,A] J A G [S,B,H] K [S,C,G] I N C receives RREQ from G and H, but does not forward it again, because C has already forwarded RREQ once

Route Discovery in DSR Y Z S E F [S,E,F,J] B C M L J A G H [S,B,H,I] D K I N [S,C,G,K] J and K both broadcast RREQ to D Their transmissions may collide at D

Route Discovery in DSR Y Z S E [S,E,F,J,M] F B C M L J A G H D K I N D does not forward RREQ, because D is the intended target

Route Reply in DSR Y Z S RREP [S,E,F,J,D] E F B C M L J A G H D K I N Represents RREP control message

An Example of Route Maintenance B A S E F H J D C G I K Z Y M N L RERR [J-D] Route Error Packet : RERR J sends a route error to S along route J-F-E-S when it finds link [J-D] broken Nodes hearing RERR update their route cache to remove all invalid routes related with link J-D

Use of Route Caching Can Speed up Route Discovery B A S E F H J D C G I K Z M N L [S,E,F,J,D] [E,F,J,D] [C,S] [G,C,S] [F,J,D],[F,E,S] [J,F,E,S] RREQ [K,G,C,S] RREP When node Z sends a route request for node C, node K sends back a route reply [Z,K,G,C] to node Z using a locally cached route

Use of Route Caching Can Reduce Propagation of Route Requests B A S E F H J D C G I K Z M N L [S,E,F,J,D] [E,F,J,D] [C,S] [G,C,S] [F,J,D],[F,E,S] [J,F,E,S] RREQ [K,G,C,S] RREP [D,K,G,,C] Route Replies (RREP) from node K and D limit flooding of RREQ.

Route Requests in AODV Y Z S E F B C M L J A G H D K I N Represents a node that has received RREQ for D from S

Broadcast transmission Route Requests in AODV Y Broadcast transmission Z S E F B C M L J A G H D K I N Represents transmission of RREQ

Route Requests in AODV Y Z S E F B C M L J A G H D K I N Represents links on Reverse Path

Reverse Path Setup in AODV Y Z S E F B C M L J A G H D K I N Node C receives RREQ from G and H, but does not forward it again, because node C has already forwarded RREQ once

Reverse Path Setup in AODV Y Z S E F B C M L J A G H D K I N

Reverse Path Setup in AODV Y Z S E F B C M L J A G H D K I N Node D does not forward RREQ, because node D is the intended target of the RREQ

Forward Path Setup in AODV Y Z S E F B C M L J A G H D K I N Forward links are setup when RREP travels along the reverse path Represents a link on the forward path

Route Maintenance 1 2 3 S D RERR 3´ The link from node 3 to D is broken as 3 has moved away to a position 3´. Node 2 sends a RERR message to 1 and 1 sends the message in turn to S. S initiates a route discovery if it still needs the route to D.