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 sourceRequestIDdestSeq-numhops sourcedestSeq-numhops destNext-hopsSeq-numhops

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 destNext-hopsSeq-numhopsActive neighbor

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 destNext-hophopsSeq-numpath destNext-hophopsSeq-numFlow-idpath destNext-hophopsSeq-numUnreach-dest destNext-hophopsSeq-numFlow-idS-flagS-flow-idpath

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: 1.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