Mobile Communications in a Mobile Agent Based Overlay System

Mobile Communications in a Mobile Agent Based Overlay System

Ching-Feng Li

2

Issues of Mobile Agent CommunicationIssues of Mobile Agent Communication

The receiver agent may migrate to another peer How does the sender agent know the receiver agent has

migrated? How does the sender agent know the latest location of the

receiver agent?

Message reliability The receiver agent may crash when the peer it resides crash.

How to ensure that the receiver agent does not miss any message?

3

MCP C

Sender agent

MCP A

MCP B

Receiver agent

Communicationrequest

Target agent isnot here

Receiver agent migrated before sender agent tries to communicate with it

Receiver agent migrated before sender agent tries to communicate with it

4

MCP C / HCP of agent C

Agent A

MCP A / HCP of agent A

MCP B / HCP of agent B

Agent B

Sendingmessage

Connection failed

Receiver agent crashed before sender agent tries to communicate with it

Receiver agent crashed before sender agent tries to communicate with it

5

Mechanism for solving the mobile agent migration issueMechanism for solving the mobile agent migration issue

Terms MCP – Mobile Context Peer

When a mobile agent migrates from MCP A to MCP B, the mobile agent sends a message to MCP A to update its new location.

The agent can also publish its new location to the overlay network

Before making a communication, the sender agent finds the current location of the receiver agent

6

MCP C

Sender agent

MCP A

MCP B

Receiver agent

Communicationrequest

Mechanism for solving the mobile agent migration issueMechanism for solving the mobile agent migration issue

Update its new location

Forwardcommunicationrequest

7

Mechanism for solving the message reliability issueMechanism for solving the message reliability issue

Terms MCP – Mobile Context Peer HCP – Home Context Peer

Every MCP in the overlay system provides the “messaging-queue service”

The HCP of a mobile agent serves as the messaging-queue server of the mobile agent

The mobile agent publishes its HCP to the overlay network

Every message sent to a mobile agent will also be sent to its HCP if there is an error while sending the message

The message-queue will be checked when the mobile agent re-starts and then periodically

8

MCP C / HCP of agent C

Agent A

MCP A / HCP of agent A

MCP B / HCP of agent B

Agent B

Sendmessage

Connection failed

Mechanism for solving the message reliability issueMechanism for solving the message reliability issue

Send message

Check the messagequeue when re-starts,and then periodically

Retrieved thelost messages.