Agent Development Toolkits

Large scale realization of agent applications requires frameworks, methodologies and tools that support effective development of agent systems. Historically the main obstacle in agent and multi agent system development used to be the infrastructure which refers to supporting environment where agents can communicate and achieve their desired goals. However, simply having an infrastructure is usually not enough. As user-acceptance of the infrastructure depends on ease of application development, versatility of applications, support for various standards & most importantly the security of communication among agents, security of agents on remote platforms and security of mobile agent hosting platforms. Nowadays many agent development tools and platforms of different quality and maturity are available and have been employed for different applications in different parts of the world. There is so far no consensus about which tool is best for agent development. With increased popularity of agent technology, agent development has also received attention, securing its place in commercial sector as well. Thus it is worth studying various agent toolkits in depth, and to analyze their strengths & weaknesses.

According to the technical report by Nguyen & Dang [13] there are over 100 products in this category. Due to the space constraints, we would be focusing on most appealing & promising toolkits among the available choices.

ASDK or IBM-Aglet [13,8,10]

(SDK) comprises of Aglet API, the Aglet Server known as Tahiti and the Agent Web Launcher called Fiji along with documentation and sample Aglets. Aglets are basically java objects comprising of two major components i.e. Aglet Core & Aglet Proxy. Core is holder of all the internal variables and methods of an agent whereas proxy acts as an interface to the core, shielding it from any malicious interference from the outside world.

Aglet server Tahiti is an application program that works as agent server for aglets. It provides users with a good GUI and allows users to create & dispatch an agent, monitor it, dispose it off when required. It gives user the ability to set agent’s access privileges on the server. For an aglet to move to a remote host, it must have Tahiti server installed on it, which solves some of the security problems. Fiji is an applet in java which can create Aglets or retract an existing aglet into client’s web browser. This applet accepts an agent’s URL as parameter and can be embedded in a web page using HTML, like any other applet. Aglets support both agent mobility as well as predefined movement of the agent on the network also called as Itinerary. Although aglet provides weak agent mobility but that too is restricted to its own servers. Aglet works on Mobile Agent System Interoperability Facility (MASIF).Agent migration is implemented using socket mechanism. Communication among agents is achieved using synchronous and asynchronous message passing. Agent Transfer Protocol (ATP) along with Java Agent Transfer and Communication Interface (J-ATCI) also help achieve the same Although Aglet platform has wide user acceptance but it doesn’t provide much security. Its security is knitted in the concept of restricting transfer of aglets only to its own servers. Due to lack of security, state of aglets can’t be stored on any other host. No such method is provided by this tool. Scalability is another problem, since aglets are not interoperable with other platforms or their agents, due to their restriction of working with their own server. Following figure illustrates the structure of an aglet

Voyager [10,1,9 ] is an agent development tool developed by ObjectSpace, in mid-1996. ObjectSpace has been taken over by Recursion Software Inc. since 2001 and it’s now their commercial product. Latest version available is Voyager 8.0.It’s a simple yet powerful technology for creating mobile agents in Java. It was an improvement over already existing platforms like Aglets, Odyssey, Concordia etc. which only allowed developers to create agents and launch them into a network to fulfill its mission. But none allowed sending messages to a moving agent, which made it difficult to communicate with an agent once it has been launched and also for agents to communicate with other agents.

Voyager seamlessly integrated fundamental distributed computing with agent technology. It treats an agent like a special kind of object which can move independently and can continue its execution while moving around. The agent and object are different only because an agent can move autonomously whereas an object can’t. It allows an agent to send and receive Java messages to and from other agent, even while traversing the network, irrespective of its position in the network. It supports synchronous, one-way and future message modes. Whenever an agent moves, it leaves behind a forwarder object which forwards the message to its new location.

Voyager provides flexible life spans for agents, by suppo

This content is AI-processed based on open access ArXiv data.