modular mobility in t-2

[andreiolaru-ro]

Context: I have machines A and B, and I want to transfer an agent X (instance of class C) from A to B. Alternatives:

• I don't have class C on machine B, so I transfer class C, then serialize X on machine A and de-serialize it on machine B.
  • does this work between PC and Android? How does Jade do it?
• I have class C on machine B, I serialize X on machine A and de-serialize it on machine B.
• I have class C on machine B, I serialize the state S of agent X, I kill it, I create an agent X' on machine B and initialize it with state S.
  • issues: what best defines the state of the agent? will it work to [de-]serialize components or must we also define the state of the component
  • how do we load the state of the agent?
  • in case of missing components (no implementation on machine B), I must be able to store the saved state of missing components, in case the agent transfers to a machine C that has the components implemented.

Also: where do we move (and exactly how) ?

• must associate a container name to a receiver for messages
• must be able to treat 'mobility' messages separately

[andreiolaru-ro]

We will handle for now the case where the platform supports mobility.

(An alternative case would be where the mobility is handled by the system, by unloading the agent from the platform, transferring it as a message, loading it and starting it -- the platform must be able to buffer messages that cannot be delivered to the agent while it is unloaded).

(Another alternative is to be able to write a component that handles mobility without support from the platform or from the system, but it's probably not possible with the architecture as its is).

There will be a MobilityComponent. There are two cases:

• the platform has advanced support for mobility (e.g. Jade). In this case, the component only instructs the platform to move the agent
• the platform has simple support for mobility. In this case, the component will call the platform, the platform stops the agent, serializes it, sends it as a message to the destination container, there it is deserialized, loaded on the platform, and started.
  • the platform must also be able to buffer the messages sent to the agent.

Optionally, see also issue #36.

[andreiolaru-ro]

See also issue #33 about agent states.