Information Technology Reference
In-Depth Information
whether the token will be kept by α (line 4). When a resource is kept, its
threshold is raised (line 6). If α decides to pass ∆, it will add itself to the path of
∆ (Line 9) and Update(Pα[∆],∆
i
) will update how to send ∆ according to each
previously received token ∆i in α's history (line 11). If ∆ is a resource or role
token, its threshold will be decreased (line 14). Then α will choose to the best
acquaintance to pass the token to according to Pα[∆] (line 16) and record ∆ in its
history, Hα (line 18).
14.6 Mobile Agent
Along with the development of Internet application, especially the information
retrieval, distributed computing and electronic commerce, the people hope to
acquire the best service within the scope of the whole Internet, to build the
network as a whole, to make the software agent moved freely in the whole
network. The concept of mobile agent conceives gradually at this time.
At the beginning of 1990's, the General Magic proposed mobile agent concept
for the first time in industry when released its business system Telescript. Mobile
agent was defined as a kind of agent which can independently move from one
host to another in the heterogeneous network environment. Mobile agent is a
special software agent who can communicate with other agents and resources.
Besides the basic characteristic: autonomy, active and reasoning, it has the
mobility function. It can delegate the users to finish the task through moving
from one host to another host. The mobility can reduce the network load,
increase the efficiency of communication. It can adapt the dynamic environment
and has good security and fault tolerance ability.
Mobile agent can be seen as a combination of agent technology and
distributed computing technology. It is not similar with the traditional computing
model. Different with Remote Procedure Call (RPC), mobile agent can move
from one node to another. This mobility can be selected according to the
requirement. Mobile agent is also different with the common process move
because common process can not allow the process to select when and where to
move. However, mobile agent can decide where and when to move at any time.
Mobile agent is also different with the Applet in Java Language. Applet can only
move from server to client machine. Mobile agent can move both from server
and client.
Although the architecture of mobile agent is different, almost all mobile agent
systems include Mobile Agent (MA) and Mobile Agent Environment (MAE)
