Design and Implementation of the OLSR Protocol in an Ad Hoc Framework

Juan Gutiérrez PlazaSupervisor: Raimo KantolaInstructor: José Costa Requena

Networking Laboratory - Helsinki University of TechnologyOctober 2003

2

Outline

Introduction Background Motivation Objectives Framework Tests & Results Conclusions & Future Work

3

Introduction

Ad Hoc Networks Ad Hoc: For this and only this purpose Networks without infrastructure

This Master’s Thesis analyses Ad Hoc networks

It proposes a solution for Ad Hoc problems (e.g. routing problem)

4

Background (1/6)

Ad Hoc Networking Networks without infrastructure All nodes are capable of moving Nodes work as routers No wire connections Flexible topology

5

Background (2/6)

Ad Hoc networking is being studied deeply Very important applications

Maritime communications Conferences and congresses Military applications

Advantages Networks without geographical constraints in

fixed networks Flexible topology for a variety of applications No wire connections

6

Background (3/6)

Problems Routing is very hard!

Nodes are constantly changing Security

Vulnerabilities… Small devices

Batteries, little computing power…

7

Background (4/6)

Type of routing protocols Pro-active

Routes are known beforehand DSDV, OLSR…

Re-active Routes are searched for only when needed DSR, AODV, TORA…

Hybrid Mix pro and re-active solutions ZRP

8

Background (5/6)

The OLSR Protocol (1/2) Proactive protocol

Link state based (routes are known beforehand)

Exchange topology information with other nodes of the network regularly

Based on Multi Point Relays (MPRs) MPRs minimize flooding Selected nodes which forward broadcast

messages during the flooding process

9

Background (6/6)

The OLSR Protocol (2/2) MPRs (continued)

MPRs of a given node must cover all two hop nodes away from the initial node

Type of control messages Hello. Neighbour sensing TC. Topology Control. This

messages are forwarded like usual broadcast messages

10

Motivation

Creating an Ad Hoc Framework architecture based on multiprotocol nodes Nodes run different routing protocols Protocols collaborate during the lifetime

of the Ad Hoc network Studying pro and re-active protocols

working together Exploring new algorithms for Ad Hoc

networks

11

Objectives (1/2)

Implementing the OLSR Protocol Designing and implementing some

modules of the framework The Common Cache The Registry The Common Cache Registry Server

(CCRS) Running OLSR and AODV in the

same node Reaching nodes in different types of

networks

12

Objectives (2/2)

■ My work ■ Mixed work ■ Not implemented yet

13

Framework (1/4)

Complete routing architecture for Ad Hoc networks

Modules Independent routing module Common Ad Hoc module

Common Cache Register Server (CCRS) Common Registry Common Cache Control Logic

Kernel Routing Table

14

Framework (2/4)

The Ad Hoc Framework block diagram

15

Framework (3/4)

Objectives Collecting information from each

protocol Evaluating this information Choosing the best values for protocol

parameters in order to improve the performance

Sending and receiving packets of other nodes running a different protocol

16

Framework (4/4)

Operations Register a protocol Unregister a protocol Add a new route Delete a route Get a protocol configuration Set a protocol configuration

17

Tests & Results (1/5)

Configuration 6 nodes (5 iPAQs and 1 laptop) All nodes were running a GNU/Linux

operating system One MANET interface per node OLSR and/or AODV Inside the Electrical & Communications

Department building

18

Tests & Results (2/5)

Test 1 Fully meshed nodes

running OLSR Excellent behaviour Maximum time for

discovering a route: 7 s Average delay: 3.117 ms 0% packet lost Incoming control packet

load: ~0.9 KB No broken links

19

Tests & Results (3/5)

Test 2 Nodes aligned within node range coverage

running only OLSR Ping from the first node to the last node Many broken links Strange behaviour (interference or bugs?) 12% packet lost Average delay: 27.7 ms Maximum time for discovering a route: 15 s Incoming control packet load: ~0.4 B

20

Tests & Results (4/5)

Test 3 Nodes connected through a single intermediate

node OLSR

Excellent behaviour Maximum time for discovering a route: 15 s 2% packet lost Incoming control packet load: ~0.5 B Some broken links

21

Tests & Results (5/5)

OLSR+AODV AODV couldn’t find OLSR nodes but OLSR nodes

could find AODV nodes Very good behaviour (similar to previous case) Common modules worked very well and central

node managed perfectly both protocols

22

Conclusions & Future Work (1/2)

Conclusions OLSR works quite well with static nodes The behaviour is worse when nodes are

moving (links are broken) With several hops the protocol has a

strange behaviour (interferences or bugs?), the behaviour is different every time the test is performed

Framework improves the performance of protocols running alone

23

Conclusions & Future Work (2/2)

Future work Implementing the Control Logic module Studying if the Control Logic algorithm

can be satisfied by devices with reduced computational power (e.g. iPAQs)

Deeper study of the cooperation of protocols in the framework and their performance

24

Thank you!, Kiitos!, ¡Gracias!

Any questions?