1. D’Agents: A Mobile-Agent System
Dartmouth
D’Agents: A Mobile-Agent
System
Dartmouth
College
(URL: Contact:
Why mobile agents?
Examine: Phone-call monitoring
What is a mobile agent?
Most general form of mobile code
Process that migrates under its own control from machine to machine
First name:
Bob
Identity
Database
New phone calls
Last name:
Gray
Phone Call
Database
Weight:
140
3. Agent jumps to phone machine.
Search engine
Height:
5’8”
...
2. Agent gets names.
Machine A
Machine B
Agent gets name list and starts the phone-call query without interaction with analyst’s machine.
4. Agent gets calls with right time/ region and uses name list to “score” them.
D’Agents
Dartmouth’s mobile-agent system
Multiple agent languages
Tcl
Java
Scheme
Protection against malicious agents
Many support services (directory, nagivation, debugging, etc.)
1. Agent jumps to identity machine with query.
5. Agent sends calls back to analyst.
Agent sends back only those phone calls with a high score.
How efficient are mobile agents?
Download documents and filter locally (client/server)
vs. send mobile agent and filter on the database
machine (D’Agents)
Transport (TCP/IP)
Server
Java VM
Tcl
interp.
Scheme
Agents
VM / Interpreter
Security
State
Capture
stubs
Filesystem
Manager
Tcl interpeter (kernel)
Tcl interpeter (agent)
Files
1. Authenticate
2. Accept or reject
3. Resume execution
4. open tutorial.ppt r
5. Access request (read) and security vector
{owner, untrusted machines?}
6. Yes / no / quantity
7. If yes, open
D’Agents
Architecture
D’Agents (Java, 100% relevance)
D’Agents (Java, 20% relevance)
D’Agents (Java, 0% relevance)
Client/Server
Lessons Learned
Multiple languages extremely useful
Mobile code/agents can outperform client/server in many applications …
… but significant system engineering is required.
Dartmouth