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提出 Loop Free Multi-Path Routing 協定. why: 1. 行動節點 傳輸距離限制 和 任意移動 造成 路徑中斷 和 拓樸改變 2. 減少 重找路的 成本 3.Loop Free P9. 模擬比較 Ant Mobility model(trace model) 和 RandomWay Mobility model(synthetic model) (使用 DSDV DSR AODV ). why: 分析無線網路的繞路效能,需 Mobility Model 模擬行動節點的移動性
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提出Loop Free Multi-Path Routing協定 • why: 1.行動節點傳輸距離限制和任意移動 造成路徑中斷和拓樸改變2.減少重找路的成本3.Loop Free P9
模擬比較Ant Mobility model(trace model)和RandomWay Mobility model(synthetic model)(使用DSDV DSR AODV) • why: • 分析無線網路的繞路效能,需Mobility Model模擬行動節點的移動性 • Mobility Model有2種:軌跡(trace)和合成(synthetic) 不同環境有不同移動模組,要記錄這些行動節點的軌跡資料是不易的,所以模擬皆用合成,但軌跡模組較精準
AODV(1/5) • Each node maintain routing table • Format of routing table • Format of control packets • RREQ • RREP
AODV(2/5) • Seq-num (Sequence number):由source得到destination的route最新順序號碼(ex:time),越大越新 ,由destination counter所給,初始為0 • RequestID:source的計數器,每廣播一次Route Request遞增 • Source加RequestID唯一可識別RREQ,判斷重複封包
AODV(3/5) Route discovery procedure • Source : broadcast a RREQ to its neighbors • Intermediate node receive RREQ: 1.在history table比對(Source , RequestID) 2.If It has route to dest and Seq-num is bigger, it send back RREP to source 3.Otherwise it build a reverse link in its routing table with a timer and re-broadcast RREQ • Dest receive RREQ : copy source , dest and hops of RREQ to RREP and get Sequence number in memory counter
AODV(4/5) Route reply procedure Dest : send RREP to source along reverse link Intermediate node receive RREP: It build a forward link to dest and send RREP to source along reverse link Source :create entry
AODV(5/5) • Routing table maintenance • 每個節點定期廣播一個hello message給neighbors並回應,無回應則表示節點不直接連接 • Active neighbor(有效鄰近節點):紀錄最近某段時間內,對dest送來封包之鄰近節點 • 檢查會經過此消失節點的路,有效鄰近節點會被告知此路不通,需清除路由表,有效鄰近節點會再告知其有效鄰近節點
DSR • DSR和AODV主要的不同在於RREQ、RREP和RERR具有complete path from source to destination
LFMPR(1) • Base on AODV • Use DSR concept to construct multiple paths • Path: complete path of a packet passing through • 無source and RequestID
LFMPR(2) RREQ RREP RERR Routing table
LFMPR(3) Route discovery procedure • Source : • If no entry, it queue the data packet • Generate RREQ and add node ID in path • broadcast a RREQ to its neighbors
LFMPR(4) • Intermediate node receive RREQ: • record more than one(max m) reverse link (multi-reverse link)and path field in routing table 2.If It has route to dest and Seq-num is bigger, it send back RREP to source 3.Otherwise it build a reverse link in its routing table with a timer and add node ID in path field and re-broadcast RREQ once
LFMPR(5) • Dest receive RREQ : copy source , dest , hops and path of RREQ to RREP and get Sequence number in memory counter
LFMPR(6) Route reply procedure Dest : send RREP to source along reverse link Intermediate node receive RREP: 1.Complete the multi-reverse link 2.if RREP has flow-id ,record it to S-flow-id 3.New a flow-id for each multi-reverse link and add it in RREP 3.Send RREP to each multi-reverse link
LFMPR(7) • Source : add flow-id in the data packet and forward it • EX:P13 P16 • S-flag is indicate that the flow-id in a data packet must switch to s-flow-id during the data forwarding phase
LFMPR(7/7) • Routing table maintenance • If transmission is broken, intermediate choose backup path and change flow-id of data packet and forward next hop • If it has no entry to destination (unreachable) , it broadcast RERR packet to neighbors and they remove entry in routing table • P17
The Performance analysis of LFMPR Metrics suggested by IETE MANET working group for routing protocol evaluation 1.throughput ratio 2.Average End-to-end Delay 3.Normalized Routing Load
throughput ratio P20 • The radio of data packet received by destination • LFMPR is higher than AODV • Current routing path broken, packets be sent with another path without performing any queue procedure which increasing the throughput ratio
Average End-to-end Delay P21 • Average End-to-end Delay of data packets includes buffering during route discovery, queuing delay, retransmission delay • Average End-to-end Delay in LFMPR is less than that in AODV • Because once the transmission path breaks, the intermediate node chooses backup path immediately for sending the data
Normalized Routing Load • Total number of control messages (RREQ,RREP,RRER) • RREQ (P22) is less: path broken • RREP(P22) is more: construct multiple paths (multi-reverse links) • RERR(P23)is grown slowly: path broken ,the intermediate nodes need to broadcast a RERR packet
RandomWay Mobility model(synthetic model) • A mobility model includes the change in speed and direction of each MNs • The movement of each mobile node • 1.It selects a random destination • 2.Select a random speed • 3.move to destination • 4.After reaching the destination • 5.pause a random time • 6.repeat1.
Ant Mobility model (trace model) • P27 • 給參數map size, ant size ,food size, etc to a tool( ant mobility model) P31 • 他將模擬ant移動( ant 為mobile node),記錄移動方向和速度於一個TCL檔,給NS2模擬 P29
評估3項優點 1.throughput ratio 2.Average End-to-end Delay 3.Normalized Routing Load 發現ant mobility model 都較好