On using route cache in route discovery mechanism in mobile ad-hoc network

Other Title(s)

في استخدام المسارات المخزنة في الذاكرة السريعة في آلية استكشاف المسارات في الشبكات الخاصة المتحركة

Dissertant

al-Khazailah, Mazid Taha Awwad

Thesis advisor

Ababinah, Ismail M.
Samawi, Venus W.

Comitee Members

Bani Muhammad, Sad
al-Mubayyidin, Wisam
Battayihah, Khalid

University

Al albayt University

Faculty

Prince Hussein Bin Abdullah Faculty for Information Technology

Department

Department of Computer Science

University Country

Jordan

Degree

Master

Degree Date

2013

English Abstract

Dynamic Source Routing (DSR) is one of the Ad hoc routing protocols.

Propagation of route discovery and route maintenance packets along the network is costly.

Route caching is used to speed up route discovery and to reduce propagation of route requests.

When an intermediate node receives route request packet, it replies from its cache if it has a cached route to the destination.

Although route caching enhances the performance of DSR protocols, but stale cache entries will lead to performance degradation, when we are near the destination.

In this case, the probability of obtaining a fresh route to the destination is higher without using route cache. The question is, when to use the cache, and when to stop using it.

In other words, what is the suitable threshold value that makes using cache more effective? To answer this question, we carried out an empirical study to determine suitable threshold value that supports the decision of using route cache.

Based on this study, it was detected that half of the network diameter is the most suitable threshold value. Another feature, concerning route caching, is the ability of caching any heard routes including multiple routes per destination.

This feature may cause a problem since cache has limited size.

We investigate that suitable cache size that caches the freshest routes instead of caching any routes without using any caching criteria.

The question is, which route should be cached and which route should be removed.

To answer this question, we keep only two routes for specific destination.

These two routes are selected based on two caching criteria: freshness, and hop count.

Initially, we ensure that the route satisfies freshness criterion, then the comparison is done based on hop count criterion.

We achieved freshness criterion by selecting the route that is generated by complete broadcasting of route request. GLOMOSIM simulator is used to evaluate the suggested Enhanced DSR (EDSR).

In simulation, we used several parameters for evaluating the performance of the algorithms: pause time, number of CBR (Constant Bit Rate) sources, and transmission rate.

The pause time represents the amount of time a node stays without moving.

The number of CBR sources represents the number of sources sending data packets to their destinations.

We have evaluated EDSR in comparison with Basic DSR for different three scenarios, each has three cases.

The scenarios randomly chose by permutation these three parameters.

Simulation results show significant improvement over Basic DSR up to 22 % in packet delivery ratio, up to 63% in control overhead, and up to 27% in average end-to-end delay.

Main Subjects

Information Technology and Computer Science

Topics

• Ad hoc networks

No. of Pages

73

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-321725