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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
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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.