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Agent agent 2002 6 4. Outline of Presentation Introduction: Inter-Agent Message Passing ARP: Design and Analysis Generalization: A Generic Framework Conclusion.

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Presentation on theme: "Agent agent 2002 6 4. Outline of Presentation Introduction: Inter-Agent Message Passing ARP: Design and Analysis Generalization: A Generic Framework Conclusion."— Presentation transcript:

1 agent agent

2 Outline of Presentation Introduction: Inter-Agent Message Passing ARP: Design and Analysis Generalization: A Generic Framework Conclusion and Future Work

3 Introduction: Basic Concepts Mobile Agents – Mobile Agents are autonomous objects or object clusters, which are able to move between locations in a so-called mobile agent platform. (Mole, U of Stuttgart) Mobile Agent Platform – A mobile agent platform is a distributed abstraction layer that provides the concepts and mechanisms for mobility and communication on one hand, and security of the underlying system on the other hand.

4 Why Message Passing Mobile Agent System can be used as General-Purpose Distributed Computing Middleware Platform. Sometimes Message Passing is more efficient than migration There DO exist MA-based applications that needs remote message passing between cooperating agents.

5 Inter-Agent Message Passing - Requirements Location Transparency – Message sender does not need to know the physical location of the receiver agent, whose address changes frequently by moving from one host to another. Reliability – The concurrent and asynchronous nature of message forwarding and agent migration may cause message loss or chasing problem. – By reliability we mean the message can reach the target agent by a bounded number of forwarding.

6 MAP

7 Inter-Agent Message Passing - Requirements Efficiency – Low location updating overhead – Low message delivery overhead Asynchrony – Asynchronous execution – Little constraint on the mobile agent mobility. Adaptability – Suit different Communication and Migration Pattern

8 Introduction: Inter-Agent Message Passing ARP: Design and Analysis – Design of ARP – Analysis of ARP – Improvements Generalization: A Generic Framework Conclusion and Future Work

9 Design of ARP (Adaptive and Reliable Protocol) Mobile IP solution Extention1: Mobile IP + Synchronization Extension2: Distributed Home Scheme Extension3: Mailbox-Based Scheme = ARP

10 Mobile IP Solution MAP MAP-Home Reg

11 Design of ARP Mobile IP solution – No Reliability Support Extention1: Mobile IP + Synchronization – The agent home coordinates message passing and agent migration Extension2: Distributed Home Scheme Extension3: Mailbox-Based Scheme = ARP

12 MAP Mobile IP + Synchronization MAP MAP-Home Dereg ACK Reg

13 MAP-Home MAP Mobile IP + Synchronization MAP Dereg ACK Reg

14 Mobile IP + Synchronization MAP MAP-Home Dereg ACK

15 Mobile IP + Synchronization Pros – Simple – Guarantee reliable message delivery Agent has received all the message on transmission before migration Message forwarding is suspended during agent migration Cons – Rely too much on the agent home Performance bottleneck Single-point-of-failure Asynchronous execution – Triangle Routing

16 Design of ARP Mobile IP solution Extention1: Mobile IP + Synchronization Extension2: Distributed Home Scheme – Decentralize the role of agent home to all the hosts on the migration Path – Caching Mechanism Extension3: Mailbox-Based Scheme = ARP

17 MAP-4 Distributed Home Scheme MAP-1 MAP-3 MAP-2 MAP-5

18 MAP-4 MAP-3 MAP-2 MAP-1 Distributed Home Scheme MAP-5

19 Distributed Home Scheme MAP-4 MAP-1 MAP-3 MAP-2 MAP-5

20 Caching Mechanism MAP-1 MAP-2 MAP-3

21 Distributed Home Scheme Pros – Location Transparency, Reliability – Reliance on the agent home is reduced – Locality of Communication (No Triangle Routing) Cons – Migration Cost is Un-Affordable – Delay of Migration is prohibitive

22 Design of ARP Mobile IP solution Extention1: Mobile IP + Synchronization Extension2: Distributed Version Extension3 (ARP): Mailbox-Based Scheme

23 Design of ARP -The Mailbox-Based Scheme MAP MB

24 Design of ARP -The Mailbox-Based Scheme Communication between agents is divided into two steps – Message transmission from the sender to the receivers mailbox Identical with inter-agent Communication Distributed Home Scheme is used – Delivery of the message from the mailbox to its owner agent Push or Pull

25 ARP-Adaptive and Reliable Protocol MAP-1 MAP-3 MAP-5 MAP-4 MB MAP-2 MB MAP-6 MB

26 MAP-4 MAP-5 MB MAP-1 MB MAP-2 MAP-3 MB MAP-6 MB

27 MAP-4 MAP-5 MB MAP-1 MB MAP-2 MAP-3 MB MAP-6 MB

28 Properties of ARP Location Transparency – Home + Caching Mechanism Reliability – Synchronization is used Asynchronous Migration Adaptability – Mobile IP + Synchronization – Distributed Home Scheme Efficiency

29 Introduction: Inter-Agent Message Passing ARP: Design and Analysis – Design of ARP – Analysis of ARP – Improvements Generalization: A Generic Framework Conclusion and Future Work

30 ARP: Design and Analysis Analysis – Migration of the mailbox When to migrate Impact of migration frequency on the performance – Interaction between the mailbox and the agent Push or Pull Improvement – Path Compression and Garbage Collection – Fault-Tolerance Issues

31 Impact of the migration frequency on the performance

32 Introduction: Inter-Agent Message Passing ARP: Design and Analysis Generalization: A Generic Framework – Design Space of the mailbox-based scheme – Three-Dimensional Framework – Particular Protocols Conclusion and Future Work

33 Design Space of the Mailbox- based Scheme Migration of the mailbox Interaction between the agent and its mailbox: Push or Pull? Synchronization – Sender The mailbox – The mailbox Its owner agent

34 Generalization – A Generic Framework NM JM FM X (Migration Frequency) Y (Delivery Mode) PL PS NS SHM (SMA) FS Z (Synchronization)

35 The Generic Framework -Particular Protocols Parameter Combination – The three dimensions are orthogonal – Protocol: XX-YY-ZZ Home-Server Based Protocols – NM-PS-NS: Identical to Mobile IP – NM-PS-SMA: Mobile IP + Sync – NM-PL-NS: Pull mode is used

36 Forwarding Pointer Based Protocols – FM-*-NS – JM-PL-NS – JM-PS-NS Distributed Registration-Based Protocols – FM-*-SHM (Distributed Home Scheme) – JM-PS-FS – JM-PL-SHM (ARP) When to use which protocol?

37 Conclusion and Future Work The mailbox based scheme introduces – Flexibility and adaptability – Reduction of the constraint on the agent mobility. – Better balance between migration cost and message delivery cost

38 Conclusion and Future Work Based on the scheme – The Generic Framework can be used to: Describe and evaluate various MA communication protocols Help users to clearly specify their requirements Help users to design flexible and adaptive protocols which can be customized to meet their requirements – The ARP protocol derived from the framework can satisfy the requirements of a protocol Location Transparency Reliability Asynchrony Efficiency and Adaptability

39 Conclusion and Future Work – Modeling mobility of mobile agents – Extend the mailbox-based scheme for mobile agents multicast Future work

40

41 – agent Vol.25, No. 4, 2002, pp – An Efficient Mailbox-Based Algorithm for Message Delivery in Mobile Agent Systems Proc. of MA2001, pp – Internet agent – Design of Efficient Mobile Agent Communication Protocols


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