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Mobile Agents By Olga Gelbart What is an agent? A program (software agent), e.g., Personal assistant.

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Presentation on theme: "Mobile Agents By Olga Gelbart What is an agent? A program (software agent), e.g., Personal assistant."— Presentation transcript:

1 Mobile Agents By Olga Gelbart

2 What is an agent? A program (software agent), e.g., Personal assistant (mail filter, scheduling) Information agent (tactical picture agent) E-commerce agent (stock trader, bidder) Recommendation agent (Firefly, Amazon.com) A program that can –interact with users, applications, and agents –collaborate with the user Software agents help with repetitive tasks

3 Is everything an agent? Not all programs are agents Agents are –customized –persistent –autonomous –adaptive

4 What is a mobile agent? Machine AMachine B Search engine Mobile agent: Agent that migrates from machine to machine in a heterogeneous network at times of its own choosing

5 Definition In a broad sense, an agent is any program that acts on behalf of a (human) user. A mobile agent then is a program which represents a user in a computer network, and is capable of migrating autonomously from node to node, to performs some computation on behalf of the user.

6 How it works? Agen t Host A Host B Host C Agent Network

7 Mobile Agent Attributes Code State –Execution state –Object state Name –Identifier –Authority –Agent system type Location

8 Evolution of the mobile agent paradigm

9 Assumptions about computer systems violated by mobile agents Whenever a program attempts some action, we can easily identify a person to whom that action can be attributed, and it is safe to assume that that person intends the action to be taken. Only persons that are know to the system can execute programs on the system. There is one security domain corresponding to each user; all actions within that domain can be treated the same way. Single-user systems require no security. Essentially all programs are obtained from easily identifiable and generally trusted sources The users of a given piece of software are restrained by law and custom from various actions against the manufacturers interests

10 Assumptions violated by mobile agents (contd) Significant security threats come from attackers running programs with the intent of accomplishing unauthorized results. Programs cross administrative boundaries only rarely, and only when people intentionally transmit them. A given instance of a program runs entirely on one machine; processes do not cross administrative boundaries at all. A given program runs on only one particular operating system. Computer security is provided by the operating system

11 Benefits of mobile agents Bandwidth conservation Reduction of latency Reduction of completion time Asynchronous (disconnected) communications Load balancing Dynamic deployment

12 Reason 1: Bandwidth conservation Server Dataset Text documents, numerical data, etc. Client/Proxy Server Dataset

13 Reason 2: Reduce latency Sumatra chat server (a reflector) 1. Observe high average latency to clients 2. Move to better location

14 Reason 3: Reduce Completion Time Efficiency Mobile users 1. Send code with unique query 2. Perform multi-step queries on large, remote, heterogeneous databases 3. Return requested data Low bandwidth channel

15 Reason 4: Disconnected communication and operation X X X X Before After

16 Reason 5: Load balancing Jobs/Load Jobs/Load migrate in a heterogeneous network of machines

17 Unique needs: maps, weather, tactical updates.... Command post Tactical updates Map, terrain databases Weather Reason 6: Dynamic Deployment

18 Threats posed by mobile agents Destruction of –data, hardware, current environment Denial of service –block execution –take up memory –prevention of access to resources/network Breach of privacy / theft of resources –obtain/transmit privileged information –use of covert channels Harassment –Display of annoying/offensive information –screen flicker Repudiation –ability to deny an event / action ever happened

19 Protection methods against malicious mobile agents Authenticating credentials –certificates and digital signatures Access Control and Authorization –Reference monitor –security domains –policies Software-based Fault Isolation –Javas sandbox Monitoring –auditing of agents activities –setting limits Proxy-based approach to host protection Code Verification - proof-carrying code

20 Threats to mobile agents –Denial of service –Unauthorized use or access of code/data –Unauthorized modification or corruption code/data –Unauthorized access, modification, corruption, or repeat of agent external communication

21 Possible attacks on mobile agents Denial of service Impersonation –Host –Agent Replay Eavesdropping –Communication –Code & data Tamper attack –Communication –Code & data

22 Protection of mobile agents Encryption –code –payload Code obfuscation Time-limited black-box security

23 Application: Technical reports Dynamically selected proxy site 1. Send agent 3. Return merged and filtered results GUI on home machine Machine n Machine Send child agents / collect partial results

24 Application: Military Wireless Network Technical specs Orders and memos Troop positions Wired network

25 Application: e-commerce Bank Arbiter VendorA Yellow pages VendorB Agent

26 Mobile agent systems

27 More examples and bots Tryllian mobile agent system Bots –mysimon.com –amazon.com - customer preferences

28 Current trends lead to mobile agents Information overload Diversified population Bandwidth gap Mobile users and devices Customization Proxy-based Server-side Avoid large transfers Disconnected Operation Mobile code to client Mobile code to server or proxy Mobile Agents High latency Increased need for personalization Too many unique, dispersed clients to handle Multiple sites to visit Avoid star itinerary

29 Migrating to migrating code Applets Proxies that accept servlets Services that accept servlets Proxies provided by existing ISPs Mobile Agents Intranet Internet

30 Conclusion: Cons Security is too big a concern Overhead for moving code is too high Not backward compatible with Fortran, C …. Networks will be so fast, performance not an issue

31 Conclusion: Pros A unifying framework for making many applications more efficient Treats data and code symmetrically Multiple-language support possible Supports disconnected networks in a way that other technologies cannot Cleaner programming model

32 For more information... Mysimon.com DAgents: Tryllian: Aglets:


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