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Explore differences in mobile ad hoc networks from wired networks, protocol classifications, and detailed overviews of DSDV, DSR, AODV, and TORA routing protocols. Conduct qualitative comparisons and analysis using NS2 simulation tool.
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Comparion of Routing Protocols For Mobile Adhoc Networks Boqun Zuo Huiming Wang
Mobile Ad hoc network(MANET) Difference from Wired Network: • Dynamic network topology • No center networks, self-organizing • Multihop networking • Limited transmission bandwidth and changing wireless link capacity • ......
DSDV(Destination-Sequenced Distance-Vector Routing) Metric:hops from source node to destination node Seq:sequence of dest node,created by dest node • Broadcast routing table to neighbor nodes periodically • routing select:the newest sequence then the least metric • Each node maintains a routing table:
DSDV (Tables) 1 2 A B C
DSDV (Route Advertisement) B increases Seq.Nr from 100 -> 102 B broadcasts routing information to Neighbors A, C including destination sequence numbers (A, 1, A-500) (B, 0, B-102) (C, 1, C-588) (A, 1, A-500) (B, 0, B-102) (C, 1, C-588) 1 1 A B C
DSDV (Respond to Topology Changes) Immediate advertisements Information on new Routes, broken Links, metric change is immediately propagated to neighbors. Full/Incremental Update: Full Update: Send all routing information from own table. Incremental Update: Send only entries that has changed. (Make it fit into one single packet)
DSDV (New Node) 2. Insert entry for D with sequence number D-000Then immediately broadcast own table 1. D broadcast for first timeSend Sequence number D-000 (D, 0, D-000) A B C D
DSDV (New Node cont.) 3. C increases its sequence number to C-592 then broadcasts its new table. 4. B gets this new information and updates its table……. (A, 2, A-550) (B, 1, B-102) (C, 0, C-592) (D, 1, D-000) (A, 2, A-550) (B, 1, B-102) (C, 0, C-592) (D, 1, D-000) ……… ……… A B C D
DSDV (no loops, no count to infinity) 2. B does its broadcast-> no affect on C (C knows that B has stale information because C has higher seq. number for destination D)-> no loop -> no count to infinity 1. Node C detects broken Link:-> Increase Seq. Nr. by 1(only case where not the destination sets the sequence number -> odd number) (D, 2, D-100) (D, 2, D-100) D A B C
DSDV (Immediate Advertisement) 3. Immediate propagation B to A:(update information has higher Seq. Nr. -> replace table entry) 2. Immediate propagationC to B:(update information has higher Seq. Nr. -> replace table entry) 1. Node C detects broken Link:-> Increase Seq. Nr. by 1(only case where not the destination sets the sequence number -> odd number) (D, , D-101) (D, , D-101) D A B C
DSR(Dynamic Source Routing) routing discovery:sourse node want to send packets to dest node but there isn't a route cache sourse node floods routing requeset(RREQ) route cache:sourse node receive RREP,cache the route RREP:node receive RREQ, and there are route caches to dest node,then send route reply
AODV(Ac-hoc On-Demand Distance Vector Routing) • AODV is a comprehensive protocol between the DSDV and DSR. It follows the routing table and dest node sequence in DSDV, and uses route discovery in DSR.
AODV (Example) A L Y F J B K D P G S C E H I T Z RREQ
AODV (Example) A L Y F J B K D P G S C E H I T Z Reverse Path Setup
AODV (Example) A L Y F J B K D P G S C E H I T Z
AODV (Example) A L Y F J B K D P G S C E H I T Z
AODV (Example) A L Y F J B K D P G S C E H I T Z RREP
AODV (Example) A L Y F J B K D P G S C E H I T Z Forward Path Setup
AODV (Example) A L Y F J B K D P G S C E H I T Z
AODV (Example) A L Y F J B K D P G S C E H I T Z
AODV (Example) A L Y F J B K D P G S C E H I T Z
TORA(Temporary Ordered Routing Algorithm) • Each node has a height calculated by the routing protocol for dest node. • Each node maintains a neighbour table containing the height of the neighbour nodes. • The route is to select a lower height untill find the dest node.
Simulation • Tool: NS2(Network Simulator,version 2) • Protocal:AODV • DSR • DSDV • TORA(?)
The simulation scenario • NS2-setdest&cbrgen • Topology: • the number of nodes is 50 • the maxspeed of nodes is 20 • the pausetime of nodes
The protocol performance • index: • packet delivery ratio • ∑num of pkt receive/∑num of pkt send • average end-to-end delay • ∑(arrive time-send time)/∑num of connections • routing overhead • ∑num of (send pkt +forward pkt)
Qualitative comparison of the four typical routing protocols
Analysis • As the pause time increase from 0 to 100s.The packet delivery ratios of the three routing protocals remain stable. But the packet delivery ratios of AODV and DSR are much higher than DSDV. • And the DSR has the highest end-to-end delay, AODV followed, DSDV is lowest and stable. • AODV routing overhead is the bigest and has an increasing trend. DSDV and DSR routing overhead is relatively small.