PRESENTED BY: ABDALLA ELAOGALI

Mobile Agents

THE LIBYAN ACADEMY COMPUTER SCIENCE

Agent Systems

Fall 2013

Outline

IntroductionWhat are Agents?What is a Mobile AgentStatic and Mobile AgentMore about Mobile AgentsWhy use Mobile Agents?Working of Mobile AgentsThe life cycle of a Mobile Agen

Outline - cont

Agent Migration StrategiesoStrong Migration

oWeak MigrationProperties of Mobile Agents

Agent Communication StrategiesApplications of Mobile Agents

Advantages of Mobile AgentsDisadvantages of Mobile Agents

Security IssuesConclusions

References

What are Agents?

The concept of agents is not an unfamiliar one. The precepts of agent technology have

existed in many of the applications we use today and take for granted. For example,

your e-mail client .Recently, intelligent agents have come to

vogue.One of the most interesting and much

vaunted category of agents is mobile agents.

Anand Tripathi, University of Minnesota

5

Mobile Agents

A mobile agent is an object capable of autonomously migrating from one host to

another in a distributed system to perform actions on behalf of its creator .

Clientagent(code+data) Mobile Agent

Server 1

Server 3 Server 2

Static and Mobile Agents

Static agents achieve their goal by executing on a single machine.

mobile agents migrate from one computer to another in the network and execute on

several machines.Mobility increases the functionality of the

mobile agent and allows the mobile agent to perform tasks beyond the scope of static

agents .

Figure 1

More about Mobile Agents

A mobile agent is an active object that can move both data and functionality (code) to

multiple places within a distributed system.

A mobile agent should be able to execute on any machine within a network, regardless of

the processor type or operating system.

Figure 1

Why use Mobile Agents?

User passivity/data timelinessMulti-staged/multi-processed calculationsUntrusted collaboratorsLow-reliability/partially-disconnected

networks

Figure 1

Working of Mobile Agents

A mobile agent consists of the program code and the program execution.

Initially a mobile agent resides on a computer called the home machine.

The agent is then dispatched to execute on a remote computer called a mobile agent host.

The life cycle of a Mobile Agent

• Creation: a brand new agent is born and its state is initialized.

• Dispatch: an agent travels to a new host.

• Cloning: a twin agent is born and the current state of the original is duplicated in the clone.

• Deactivation: an agent is put to sleep and its state is saved in persistent storage.

• Activation: a deactivated agent is brought back to life and its state is restored from persistent storage.

Cont,

• Retraction: an agent is brought back from a remote host along with its state to the home machine.

• Disposal: an agent is terminated and its state is lost forever.

• Communication: Notifies the agent to handle messages incoming from other agents , which is the primary means of inter-agent correspondence.

Agent Migration Strategies

Strong MigrationThe code, data and execution state are

migrated to the next host.Weak Migration

Involves only the migration of the code and data state of the mobile agent.

Properties of Mobile Agents

Adaptive LearningMobile agents can learn from experiences

and adapt themselves to the environmentAutonomy

Mobile agents can take some decisions on its own .

MobilityMobile agents have the ability to move from

one host to another in the network.

Agent Communication Strategies

a mobile agent should interacts and cooperates with others.

To communicate with a remote mobile agent:owe must find the location of the agent and route

the message to it.oA naming scheme is needed to identify agents in

a unique fashion.oOne mechanism such as message passing,

streams, events, proxies, blackboard mechanism and CORBA as a communication protocol.

Applications of Mobile Agents

Mobile Agents are suitable for the following applications

Parallel Computing.

Data Collection.

E-commerce.

Mobile Computing.

Advantages of Mobile Agents

Reduction in bandwidth usage. Reduce total time. Reduce Latency. Disconnected Operation. Load Balancing. Dynamic Deployment.

Reduction in bandwidth usage

Dataset

Dataset

Dataset

Dynamically selected proxy site

Merged and filtered data

stream

Server

Dataset

Proxy

ProxyServer

Dataset

Reduction in bandwidth usage cont,

Overcome total time

Dataset

Dataset

DatasetFact

• Sending an agent avoids remote interaction.Goal

• Avoiding remote interaction leads to faster completion times.

Current Systems• Do not meet the goal in all network environments• Tradeoff: Local interaction vs. interpretive

overhead

Reduction in latencySumatra chat

server [RASS97]

1. Observe high

average latency to

clients

2. Move to better

location

2 to 4 times smaller

latency in trial runs

Disconnected Operation

Dataset

Dataset

Dataset

Dynamically selected proxy site

X

Agent continues its task even if the link to its home machine goes down (temporarily).

Load Balancing

Machine A Machine B

Machine A Machine B

Agent moves to balance load

Dynamic Deployment

DatasetDataset

Disadvantages of Mobile Agents

The main drawback of mobile agents is the security risk involved in using mobile agents.

Security risks in a mobile computing environment are twofold.

Conclusions

Distributed computing involving several computers in a network can be achieved

using message passing or remote procedure calls (RPC) .

ReferencesStrategies of Mobile Agent for Handling a Task.ISSN:

2277-3754 ISO 9001:2008 Certified International Journal of Engineering and Innovative Technology (IJEIT) Volume

2, Issue 1, July 2012 244 Cornell University, Department of Computer Science.

http://www.cs.cornell.edu WIKIPEDIA The Free Encyclopedia

http://en.wikipedia.org/wiki/Mobile_agentMole - Concepts of a Mobile Agent System

Dipl.-Inform. J. Baumann, Dipl.-Inform. F. Hohl, Prof. Dr. K. Rothermel, Dipl.-Inform. M. Straßer

Security Issues in Mobile Code SystemsDavid M. Chess

:// . / / /#http klynch com documents agents Refs