1. Abstract:
A certain
number of mobile agent-based monitoring mechanisms have actively been developed
to monitor large-scale and dynamic distributed networked systems adaptively and
efficiently. Among them, some mechanisms attempt to adapt to dynamic changes in
various aspects such as network traffic patterns, resource addition and
deletion, network topology and so on. However, failures of some domain managers
are very critical to providing correct, real-time and efficient monitoring
functionality in a large-scale mobile agent-based distributed monitoring
system. In this paper, we present a novel fault tolerance mechanism to have the
following advantageous features appropriate for large-scale and dynamic
hierarchical mobile agent-based monitoring organizations. It supports fast
failure detection functionality with low failure-free overhead by each domain
manager transmitting heart-beat messages to its immediate higher-level manager.
Also, it minimizes the number of non-faulty monitoring managers affected by
failures of domain managers. Moreover, it allows consistent failure detection
actions to be performed continuously in case of agent creation, migration and
termination, and is able to execute consistent takeover actions even in
concurrent failures of domain managers.
In order to determine whether existing
monitoring systems can satisfy the requirements imposed by future “networked”
systems we need to identify first these requirements. An important difference
between present day and future networking is that in the former case topology
is considered relatively static while this became an unsafe assumption for
future networks. New models of dynamic networks are constraining with the
situation in which the networks topology was mainly modified as a result of
careful planning. Examples in which logical topology layering can be
dynamically constructed in real-time are the following:
§ Dynamically
re-configurable networks
§ Active networks
§ Dynamic Virtual
Private Networks
§ Mobile and
survivable networks
§ Re-configurable
cellular networks
2. EXISTING SYSTEM
The currently available system can be categorized as
o
Static
centralized monitoring
o
Static
decentralized monitoring
Hereby the description and the functions of the above
systems would be described such that it would explain the need why we have
suggested and implemented our system.
2.1 STATIC CENTRALISED
MONITORING
In this
case there is a single monitoring station with which all the monitored systems
communicate directly. The monitoring station is in charge of collecting,
aggregating and processing raw network data.
This
model is widely used to manage relatively static, small networks using (simple
network management protocol) SNMP. The model has been criticized for its
limited responsiveness, accuracy and lack of scalability. The concentration of
management intelligence in a single point results in processing and
communication bottlenecks, limiting the number of elements that can be
monitored and the rate at which information can be gathered. Furthermore SNMP
favors a polling approach which limits the ability to track problems in a
timely manner while requiring management traffic even if no significant change
has occurred.
To
overcome the shortcomings of polling, the alternate technique of event
reporting may be used. With event reporting, the monitored systems take he
initiative to inform the manager according to pre-determined rules set by the
manager. Event reports are generated within the monitored systems either
periodically or as and when an critical event occurs.
Periodic
reporting provides the manager with status information in a summarized manner
and is more efficient than requesting the same information via polling. On the
other hand alarm reporting is used for detecting problems as soon as they
occur. The problem with alarm reporting is that the types of alarms need to be
thought-out in advance, standardized and supported by vendors. Event reporting
requires an increased level of intelligence in the monitored systems.
Typical
systems employ both polling and event reporting although in practice the
telecommunications systems rely more on event reporting and SNMP-based
management systems
2.2 STATIC DECENTRALIZED
MONITORING
One
way to increase performance and scalability is to adopt a hierarchical
management architecture which uses multiple systems with one system acting as a
main monitoring station and the others working as area monitors. Hierarchical
monitoring is used in Telecommunications Management Network (TMN). In context
of SNMP, simple monitoring and statistical probes can be introduced using RMON,
which is equivalent to an area monitor that collects monitoring information
about a number of elements within a sub-network. More recently, other forms of
decentralization based on distributed object technologies such as CORBA and
JAVA RMI have become popular in management. An extensive review of management
paradigms and technologies can be found.
The
common denominator of the above approaches in the adoption of simple,
pre-defined functionality that can actually be decentralized is restrained to
operations such as low-level filtering of monitoring data, generation of alarms
on the basis of simple conditions, and collection of rudimentary statistical
information. In addition, these decentralized area monitors operate in
pre-defined network locations, which mean that they cannot easily adapt to
network changes. Therefore, conventional static decentralized schemes, despite
coping with the scalability problem to a certain extent, inherit the other
problems of centralized management and cannot easily cope with frequently
changing, dynamic environments.
So far we have been discussing the
operations and problems concerned with the static systems. Hence to overcome
the cons of static systems, we are looking into the dynamic aspect of
methodologies of which the programmable decentralized monitoring poses some
shortcomings not satisfying the requirements.
2.3 PROGRAMMABLE
DECENTRALISED MONITORING
When we
talk about dynamic or programmable, it deploys new management logic ‘when’ and
‘where’ is needed without having to predefine the logic. With distributed
object technologies, the management logic can only be modified through software
re-installation.
The
first proposal to support remote programmability was introduced with the use of
mobile code in network management, signaling a paradigm shift from static to
dynamic management. The basic underlying principle is that new management
functions can be dynamically introduced to a managed node as required. The
manager uses the protocol to ‘push’ new code down to a managed node; management
routines are executed locally rather than centrally at management station.
Therefore, a mechanism to decentralize management processing and to re-program
managed node capability.
Managed
nodes were relatively simple in terms of processing power and there was no
uniformity in processing environments. It is the increase in processing power
and with the advent of Java that the paradigm has become a viable solution.
Java’s object serialization makes it easy to migrate code whilst Java-RMI
provides for simple communication between distributed objects.
The
single-hop mobility mechanism, despite being extremely useful as a mechanism
for flexible and dynamical remote programmability, is still a relatively static
mechanism since it is only used to deploy management logic at start up time.
The decision of ‘when’ and ‘where’ to deploy management logic is still taken by
a centralized management station based on a static network view. Because a MA
is conceived as a dynamically deployable piece of code rather than being free
to roam the network, full code mobility is not exploited to provide run-time
adaptation. Therefore, the single-hop mobility mechanism does not fully satisfy
the requirement of large-scale, highly dynamic networked systems
3. PROPOSED SYSTEM
The system that we have proposed is based
on the dynamic or programmable methodology. It satisfies the requirements to
monitor the performance for a large scale network efficiently and effectively.
It is known as the active distributed monitoring.
3.1 ACTIVE DISTRIBUTED
MONITORING
The
possible advantages of using agent mobility for network management. Some of the
pros are reduction of network traffic, increased responsiveness and robustness.
The
problem addressed here describes how to exploit agent multiple-hop mobility to
build a distributed monitoring system which reconfigures itself as the status
of the monitored system changes. Reconfigurability is an essential requirement
if the status of the monitored system is dynamic and transient. We have seen
that with distributed objects and single hop mobility we can only realize a
relatively static monitoring system that may or may not be optimized on the
basics of the initial status of the monitored system. As the latter evolves,
the distributed monitoring logic may have to be relocated in order to maintain
optimality- i.e. When MAs are used as adaptive area monitors their optimal
locations depend on the status of the network which may vary considerably in
highly dynamic environments.
The
system is decentralized because the monitored system is partitioned and
separate agents are dynamically assigned to disjoint partitions. Network
partitioning is computed in a distributed fashion by the agent system. Finally,
because agents are capable of sensing the network status and migrate at
run-time to maintain location optimality, the system is “active” or adaptive.
Such a system exploits not only multiple-hop mobility but also agent autonomy
(each agent contains the logic to independently decide when and where to
migrate) and agent cloning i.e. the ability of an agent to create and dispatch.
4. SYSTEM REQUIREMENT
4.1 HARDWARE SPECIFICATION
Processor
Type: Pentium -IV
Speed : 1.2 GHZ
Ram : 512MB RAM
Hard disk : 40GB HD
4.2 SOFTWARE SPECIFICATION
Operating System : Win2000/xp
Language : .Net,SQL server 2005
Protocol :TCP/IP
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