ABSTRACT
According to Case et al., (1990) and Pinheiro et al., (1999), the present day ways of
managing network systems as represented by Simple Network Management Protocol
(SNMP) are based on the centralized client-server approach. In this approach, the
central server (manager) retrieves raw management data from all the clients (network
elements) being managed. This raw data is centrally collated and processed by the
server for every management cycle. This is good enough for small, reliable and fast
networks that are particularly localized in nature. In present-day situation where
networks extend across cities, regions, countries, and continents; as well as in mobile
applications where connected links are very slow and expensive, this may lead to
inefficiency in terms of bandwidth utilization, resource wastage, processing bottleneck
on the server, and other problems that could be caused by communication failures
between the server and the clients being managed.
The objective of this work is to demonstrate that a more efficient approach to Network
Management could be achieved by implementing a distributed system through the use
of Mobile Agents (MA). Typically, Biesoczad et al., (1998) and Gavalas et al., (1999)
were among the early researchers who investigated the concept and possibilities of
using Mobile Agents in the management of network components. Using this concept, a
central manager generates software agents and dispatches them with predefined
itinerary and specific network management tasks; visiting each network element to be
managed; retrieving, analyzing, and only returning computed results back to the central
manager from where the agents originated. This way, the central manager does not need
to pull in huge volume of raw management data from the many dispersed network
elements being managed for central processing. This conserves expensive network
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bandwidth, relieves the central server of the mundane task of processing raw
management data that could result in processing bottleneck, and ensures that only
computed results get transmitted to the central server for display to the network
administrator.
JAVA Agent Development Environment (JADE) platform was used to develop a
Mobile Agent based network management system. Issues covered by this research
include Status monitoring of network elements, simple network management protocol
table filtering, and Global filtering on a UNICEF (United Nations Children’s Fund)
network environment that spanned across five cities (Abuja, Bauchi, Enugu, Kaduna,
and Lagos) in Nigeria. MA’s were generated and dispatched by a central server in
Abuja, visiting network elements to be managed in Bauchi, Enugu, and Lagos. In each
case, volume of data in bytes transferred in both directions as well as transit time in
seconds taken by this data were noted. Results were compared with those obtained from
the same experiments conducted using SNMP approach. Final analysis shows that while
performance was slower using MA as compared to SNMP approach, bandwidth
utilization was far much better with MA. Even the slower performance exhibited by MA
was mainly due to the JADE platform used during the implementation stage. Other
studies have shown that better throughput is attainable using other development
platforms. Also covered by this work are some security issues relating to mobile agents
in a networked environment.
TABLE OF CONTENTS
DECLARATION ……………………………………………………………………………………………. ii
CERTIFICATION ………………………………………………………………………………………….. iii
ACKNOWLEDGEMNT …………………………………………………………………………………. iv
ABSTRACT …………………………………………………………………………………………………… v
TABLE OF CONTENTS ……………………………………………………………………………….. vii
LIST OF FIGURES AND PLATES ………………………………………………………………….. xi
LIST OF TABLES ………………………………………………………………………………………… xii
ABBREVIATIONS ………………………………………………………………………………………. xiv
DEFINITIONS …………………………………………………………………………………………….. xvi
CHAPTER 1 ………………………………………………………………………………………………….. 1
GENERAL INTRODUCTION ………………………………………………………………………….. 1
1.1 BACKGROUND OF THE STUDY …………………………………………………………. 1
1.2 STATEMENT OF THE PROBLEM ………………………………………………………… 2
1.3 AIMS AND OBJECTIVES OF THE RESEARCH …………………………………….. 3
1.4 RESEARCH QUESTIONS AND HYPOTHESIS ………………………………………. 4
1.5 ORGANIZATION OF THE THESIS ……………………………………………………….. 5
1.6 CONTRIBUTION TO KNOWLEDGE …………………………………………………….. 6
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CHAPTER 2 ………………………………………………………………………………………………….. 7
LITERATURE REVIEW …………………………………………………………………………………. 7
2.1 OVERVIEW OF NETWORK MANAGEMENT ……………………………………….. 7
2.1.1 Simple Network Management Protocol …………………………………………………. 8
2.1.2 Management by Delegation (MbD) ………………………………………………………. 9
2.1.3 Remote Monitoring (RMON) …………………………………………………………….. 10
2.1.4 Mobile Agents (MA) ………………………………………………………………………… 11
2.2 JADE – JAVA AGENT DEVELOPMENT FRAMEWORK ………………………. 11
CHAPTER 3 ………………………………………………………………………………………………… 14
MATERIALS AND METHODS ……………………………………………………………………… 14
3.1 SYSTEM ARCHITECTURE ………………………………………………………………… 14
3.1.1 Network Manager ……………………………………………………………………………. 14
3.1.2 Network Element …………………………………………………………………………….. 16
3.2 MANAGER AGENT …………………………………………………………………………… 16
3.2.1 Communication of components ………………………………………………………….. 17
3.2.1.1 Receiving a Register Message ……………………………………………………….. 17
3.2.2 Manager Agent Behaviours ……………………………………………………………….. 19
3.2.2.2 Implementing Agent Bebaviour Classes …………………………………………… 20
3.3 DAEMON AGENT (NEAGENT) ………………………………………………………….. 21
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3.4 HEALTH FUNCTION (PERFORMANCE INDICATORS) ………………………. 23
3.4.1 Interface Utilization …………………………………………………………………………. 24
3.4.2 Error Rate and Accuracy …………………………………………………………………… 25
3.4.3 Internet Protocol (IP) Output Datagrams Discard Rate …………………………… 26
3.5 MESSAGE DEFINITION ……………………………………………………………………. 27
3.6 COMMUNICATION OF MANAGER AGENT WITH DAEMON AGENT…. 27
3.7 MOBILE AGENT (MA) ………………………………………………………………………. 29
3.7.1 SNMP table filtering ………………………………………………………………………… 30
3.7.2 Global Filtering ……………………………………………………………………………….. 34
CHAPTER 4 ………………………………………………………………………………………………… 37
RESULTS AND DISCUSSION ………………………………………………………………………. 37
4.1 SECURITY PROBLEM ………………………………………………………………………. 37
4.1.1 Protecting NE from malicious MA ……………………………………………………… 38
4.1.2 Protecting the important data in MA …………………………………………………… 40
4.1.3 Secure the Communication Channel ……………………………………………………. 42
4.2 SCALABILITY ………………………………………………………………………………….. 43
CHAPTER 5 …………………………………………………………………………………………………… 46
SUMMARY, CONCLUSION AND RECOMMENDATION ……………………………….. 46
5.1 SUMMARY ………………………………………………………………………………………. 46
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5.2 CONCLUSION ………………………………………………………………………………….. 47
5.3 RECOMMENDATION AND FUTURE WORK ……………………………………… 47
5.4 REFERENCES …………………………………………………………………………………… 49
CHAPTER ONE
GENERAL INTRODUCTION
1.1 BACKGROUND OF THE STUDY
According to Case et al., (1990) and Pinheiro et al., (1999), the present day ways of
managing network systems as represented by Simple Network Management Protocol
(SNMP) are based on the client-server architecture, where a central station, called the
manager collects and analyses raw data retrieved from physically distributed network
elements. In those systems, management data are stored in a standard structure
maintained on the network elements (NE) to be managed, such as Management
Information Base (MIB) Objects Tree in SNMP. Under this setup, there is always a
routine/task at each network element, such as SNMPD (Simple Network Management
Protocol Daemon) running on Linux, which periodically fetches and returns raw
management data in response to requests from the network manager.
Network management system based on Client/Server paradigm like this normally
requires transferring large amount of management data between the manager and
managed network elements. The large amount of data not only requires considerable
bandwidth, but also can cause a processing bottleneck at the manager. This is
particularly disturbing considering the fact that the bulk of the transmitted data may end
up being irrelevant and hence, discarded by the manager on arrival. As current networks
grow larger and more complicated, the problem becomes more severe (Case et al.,
1990).
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1.2 STATEMENT OF THE PROBLEM
As highlighted in section 1.1, network management based on Client/Server approach
poses a number of challenges due to its centralized nature. Some of these challenges as
extensively discussed by Bivens et al., (1999) and Bohoris et al., (2000) are:
a. Bandwidth intensive: For larger networks, management data being transferred
between the manager and the remotely located network objects being managed
becomes huge and consumes a lot of communication bandwidth. Bandwidth
today stands out as one of the most expensive resource in a typical networked
environment. This is especially the case when the network is geographically
dispersed and leased communication channels have to be utilized.
b. Processing bottleneck at Network Manager: As the data is raw, the network
manager spends a lot of time analyzing, hence, sometimes causing processing to
be slower than desired. This impact negatively on the entire management
domain where similar processing needs to be performed by the same manager
for other managed network elements. It becomes more serious when results are
needed on real-time basis and the manager is not forthcoming.
c. Resource Wastage: Worse again, in most cases, substantial part of the data is
not needed and therefore discarded by the network manager after processing,
resulting in overall resource wastage (bandwidth, processing time, storage,
memory, and so forth).
d. Effect of Communication failure: As is the case with all networked
environments, sometimes, communication breakdown does occur between the
manager and some or all the network objects being managed. This impact
negatively on the ability of the network manager to collate management data for
processing.
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Together, these challenges form the overall motivation for this research work and at the
same time, help in defining the objectives set to be achieved by the research as detailed
in section 1.3 below.
1.3 AIMS AND OBJECTIVES OF THE RESEARCH
Overall, this project work tries to solve the problems listed in section 1.2 by applying a
distributed management mechanism which overcomes the limitations posed by the
traditional centralized Client/Server architecture as presented by SNMP. The work
demonstrates that mobile agents could be used to perform network management
functions more efficiently in terms of bandwidth utilization as compared to the
traditional SNMP approach that requires a lot of communication bandwidth which
effectively reduces its utilization span in terms of network size. According to Bivens et
al.,(1999); Gavalas et al., (2000); Paliafito and Tomarchio (2000); Bohoris et al.,
(2000); and Griffin et al., (2001); Mobile Agents could be used as a decentralized
approach to network management which greatly reduces the workload at the
management server location by otherwise delegating network management
responsibilities to the network elements being managed. To be able to achieve these
desired objectives, the following approaches to network management were extensively
reviewed:
a. Remote Monitoring (RMON);
b. Management by Delegation (MbD); and
c. Mobile Agents.
Each of these three (3) alternatives mentioned above introduces some degree of
decentralization. However, the third solution, the use of Mobile Agents (MA)
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technology to distribute and delegate management tasks has been used to implement the
following aspects of network management:
a. Network elements’ status monitoring,
b. SNMP table filtering, and
c. Global filtering.
1.4 RESEARCH QUESTIONS AND HYPOTHESIS
Distinguished scholars such as Bivens et al.,(1999); Gavalas et al., (2000); Paliafito and
Tomarchio (2000); Bohoris et al., (2000); Griffin et al., (2001) have extensively
investigated the use of Mobile Agents (MA) technology to distribute and delegate
management tasks in the past.
Additionally, mobile Agent frameworks have already attracted a lot of attention in
recent years. A lot of research is currently being carried out to assess the applicability of
agent technology to network management and control environment. It has been argued
by Gavalas et al., (2000); Paliafito and Tomarchio (2000); Rubinstein et al., (2002) that
MAs have some superior features over SNMP, MbD and RMON. There is a general
agreement that MA can be used to alleviate the network manager workload and reduce
the bandwidth usage by delegation of authority from the manager to MA. Those
advancing this argument believe that MA is more flexible and could be instantly
customized by user’s requirement and launched from the manager. It can visit each
network element according to the itinerary table, computing and compressing the
management data locally, only returning the result to the network manager. By moving
a portion of the “intelligence” to the nodes where data are resident, many of the
management decisions could be taken locally, thus avoiding the transfer of large
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amounts of data from the remote nodes to the central manager (Paliafito and Tomarchio
2000).
Applicability of Mobile Agents in Network management was implemented using JAVA
Agent Development Environment (JADE) platform. Applications implemented in this
system are:
a. Network element’s status monitoring,
b. SNMP table filtering, and
c. Global filtering.
This thesis described the architecture, design and implementation details of these
applications. Common security problems of mobile agent were also investigated.
Security is a crucial problem to the feasibility of mobile agent, especially to the network
management domain which has great security requirements. Finally, the performance
of the system was tested and potential problems analyzed.
1.5 ORGANIZATION OF THE THESIS
An introduction to some background knowledge related to this research is given in
chapter 2. This includes brief overview of JADE, SNMP; a brief description of Remote
Monitoring (RMON), Management by delegation (MbD) and Mobile Agents (MA).
The overall overview of the system’s architecture is given in Chapter 3. Also discussed
in this chapter are the detailed design and implementation issues.
Results, discussions, as well as identified related problems, such as securing the whole
system and scalability test are explained in Chapter 4.
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Chapter 5 summarized, concluded and highlighted possible future work on this research
area.
1.6 CONTRIBUTION TO KNOWLEDGE
The thesis contributes to the area of network management by demonstrating that an
entirely new emerging concept of Mobile Agents technology could be used to delegate
and distribute network management responsibilities across network objects; as opposed
to the traditional Clients/Server central approach which though simple, poses a number
of operational challenges as regards to bandwidth utilization, processing bottleneck at
manager location, and difficulty in handling single point of failure. Although, an
entirely new area in modern computing, a number of studies have been undertaken by
others in the area of Mobile Agents application in network management. Bieszczad et
al., (1998) described theoretical views on applications of MA for network management.
They discussed potential uses of MA’s in network management and defined software
agents and a navigation model that determines agents’ mobility. They further listed
potential advantages and disadvantages MA’s. Gavalas et al., (1999) presented the
application of MA in bulk transfers of network monitoring data, data aggregation and
acquiring atomic SNMP table views. They analyzed the usage of mobile agents in
network management with regards to the bandwidth utilization. Pinheiro et al., (1999)
described a conceptual model which collects management related data across a
changing set of networked components and periodically computes aggregated statistics
using MA. This thesis draws ideas from above concepts and applies them differently in
the area of MA application to network management; with particular interest in Network
elements’ status monitoring, SNMP table filtering, and global filtering.
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