Location Updates For Efficient Routing In Ad Hoc Networks Adviser: Ho-Ting Wu & Kai-Wei Ke Presenter: Chih-Hao Tseng Presenter: Chih-Hao Tseng

Outline Introduction Classification of Routing Algorithms Location updates between neighboring nodes Location-based Routing Protocols Performance Evaluation issues Reference

Introduction (1/2) In MANET node mobility, activity, and availability of methods to determine absolute or relative coordinates of each node. Various approaches in literature are classified according to some criteria. Mobility is apparently a very difficult problem to handle in ad hoc networks. proposed solutions have significant drawbacks. progress has been made on the routing with known destination location, location updates issue to enable efficient routing requires further investigation.

Introduction(2/2) Qualitative PropertiesQuantitative Metrics ★ Distributed Operation. ★ Loop-Freedom. ★ Demand-based Operation. ★ Sleep Period Operation. ★ Hop counts ★ End-to-end data delay. ★ Average number of data bits transmitted per data bits delivered.

Outline Introduction Classification of Routing Algorithms Location updates between neighboring nodes Location-based Routing Protocols Performance Evaluation issues Reference

Demand-based operation Proactive -Maintain routing table when nodes move. -Unacceptable overhead. -Memorized. Reactive -Designing routes when they are needed -Source-initiated on-demand routing strategy. - Not memorized

Distributed operation Localized -Forward the message based solely -Neighboring nodes may update each other location when ever an edge is broken or created -Do not memorize past traffic at any node Non-Localized -Shortest weighted path algorithm -Each node only knows node connectivity with its own zone -significant overhead when use broadcast to find destination

Location information Using Routing Table To minimized energy required per routing task To maximize the number of routing tasks that a network can perform

Single-path vs. multi- path strategies Single-path -Full message -Lack of guaranteed delivery Multi-path -Short message -Consisting of several single-paths -Be regarded as flooding

Loop-freedom The proofs are based on the observation that distances of nodes toward destination are decreasing. S D

Memorization of past traffic To memorize previous best path for providing future path to the same destination Using Routing Table Significant overhead Needed to escape loops in directional based methods

Outline Introduction Classification of Routing Algorithms Location updates between neighboring nodes Location-based Routing Protocols Performance Evaluation issues Reference

Location updates between neighboring nodes Distance-based Update Movement-based Update

A B A’A’ B’B’ R R A ’ =A+at B ’ =B+bt The time t when the connection will be lost can be estimated by solving quadratic equation R=|A ’ B ’ |=|B-A+(b-a)t| a b

Location Update

Outline Introduction Classification of Routing Algorithms Location updates between neighboring nodes Location-based Routing Protocols Performance Evaluation Issues Reference

Location-based Routing Algorithm Original MFR GEDIR DIR LAR DREAM GREEDY GRID SP FZ GREEDY DFS Extended LAR1 、 LAR2 CH-MFR Alternate MFR Disjoint MFR R-DIR Alternate DIR Disjoint DIR f-DEDIR 2-f-GEDIR Alternate GEDIR Disjoint GEDIR VD-GREEDY f-GEDIR DGRP DGRP_DL DGRP_SDL

Request Zone Routing Distance Routing Effect Algorithm for Mobility (DREAM) Location-Aided Routing scheme 1 (LAR-1) Location-Aided Routing scheme 2 (LAR-2)

DREAM(1/3) Proactive Distribute, loop free, Multipath routing Routing table Distance effect Mobility rate S->D select one-hop neighbor Data-header: qualified to receive and forward ACK for D->S in the similar way backward

DREAM(2/3)

Advantage: -Location table -loop-free Disadvantage -Overhead increase when network grows.Often use in smaller MANET DREAM(3/3)

LAR-1

LAR-2

Doubling Circles routing Each node updates its location to all nodes located within circle of radii 2 t P, t=1,2,3 … A similar algorithm (ex: DIR method) Using squares instead of circles Additional sophisticated techniques

Directional Method (DIR) S

Quorum based Strategies To form quorums of size approximately n 1/2. Each column serves as a quorum Virtual Backbone is initiated and maintained.

Home-agent Based Strategy This is router with additional functionality Located on home network of mobile node (MN) Forwards packets to appropriate network when MN is away

When MN is at home

When MN moves to a foreign network Registration Request Registration Reply

Location Update Home agent circle

Outline Introduction Classification of Routing Algorithms Location updates between neighboring nodes Location-based Routing Protocols Performance Evaluation Issues Reference

Performance Evaluation Issues Delivery rate End-to-end data delay Communication overhead Performance on static networks MAC layer considerations Comparison with the shortest path algorithm Generating sparse and dense graphs Node mobility Simulator

Outline Introduction Classification of Routing Algorithms Location updates between neighboring nodes Location-based Routing Protocols Performance Evaluation Issues Reference

I. Stojmenovic, “ Location Updates for Efficient Routing in Ad Hoc Networks, Handbook of Wireless Networks and Mobile Computing, Wiley, 2002, uottawa.ca/~ivan, pp. 451 – /papers/21.ppt. Irene Hsu, PART 1. Introduction, 03. Wireless Internet, Irene Hsu, PART 3. Introduction, 07. Routing Protocol with MANETs (part 2), hsu.idv.tw/NTUT