220 Chapter 6 Speciﬁcations of the Kalong Mobility Model
to the mobility level (which is part of the programmer’s view) and it is the
task of the agent manager to map requirements of the mobility level to the
preferences of Kalong as described in the following sections.
6.2 Kalong Vocabulary
Kalong uses the following terms:
Agent An agent is a mobile agent as deﬁned in this book. We will often use
the term agent instance to denote a single agent object in contrast to the
set of all agents of the same type, or the agent’s type.
Agency An agency is software that is necessary to execute and migrate mobile
agents on a computer system. We distinguish between the sender agency,
which starts a transfer, and the receiver agency, to which the transfer is
Agent Manager An agent manager is a subcomponent within an agency that
conducts a migration process.
Context Kalong maintains for each agent a context data str ucture that is com-
posed of all infor mation necessary for Kalong (e.g., its name, its home
agency, its data units, its state, etc.).
Message A message is the basic unit of SATP communication. It is a sequence
of bytes matching the syntax described in the following sections.
Migration Migration is a special form of a transfer, in which agent execution
is stopped at the sender agency and resumed at the destination agency.
We deﬁne two new verb phrases to describe the direction of a migration.
When an agent leaves an agency, it migrates out and when an agent is
received by an agency, it migrates in.
Migration Strategy A migration strategy deﬁnes what agent information
should be sent to which agency; it can consist of one transfer or many
transfers. The agent manager deﬁnes the migration strategy by using the
methods of interface IKalong.
Network Connection A network connection is a virtual communication channel
between two computers that is used to transmit SATP messages.
Object State The object state,oragent object state, is equal to the serialized