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Summary

The sender intends that the receiver treat the embedded message as sent directly to the receiver, and wants the receiver to identify the agents denoted by the given descriptor and send the received propagate message to them.

Content

A tuple of a descriptor, that is, a referential expression, denoting an agent or agents to be forwarded the propagate message, an embedded ACL communicative act, that is, an ACL message, performed by the sender to the receiver of the propagate message and a constraint condition for propagation, for example, timeout.

Description

This is a compound action of the following two actions. First, the sending agent requests the recipient to treat the embedded message in the received propagate message as if it is directly sent from the sender that is, as if the sender performed the embedded communicative act directly to the receiver. Second, the sender wants the receiver to identify agents denoted by the given descriptor and to send a modified version of the received propagate message to them, as described below.

On forwarding, the :receiverparameter of the forwarded propagate message is set to the denoted agent(s) and the :sender parameter is set to the receiver of the received propagate message. The sender of the embedded communicative act of the forwarded propagate message is also set to the same agent as the propagate message’s sender.

This communicative act is designed for delivering messages through federated agents by creating a chain (or tree) of propagate messages. An example of this is instantaneous brokerage requests using a proxy message (see [FIPA00052]) or persistent requests by a request-whenmessage (see [FIPA00058]) embedding a proxy message.

Formal Model

<i, propagate(j, Ref x d(x), <i, cact>, f)> º

  <i, cact(j)>;

    <i, inform(j, I_i(($y) (B_j(Ref x d(x) = y) Ù Done(<j, propagate(y,

                     Ref x d(x), <j, cact>, f)>, B_jf))))>

    FP: FP(cact) Ù B_iaÙØB_i (Bif_jaÚ Uif_ja)
    RE: Done(cact) Ù B_ja

Where:

  a= I_i(($y) (B_j(Ref x d(x) = y) Ù

             Done(<j, propagate(y, Ref x d(x), <j, cact>, f)>, B_jf)))

Agent i performs the embedded communicative act to j: <i, cact(j)> and i wants j to send the propagate message to the denoted agent(s) by Ref x d(x).

Note: <i,cact> in the propagate message is the ACL communicative act. that is, the ACL message, without a :receiver prarmeter. Ref x d(x) is one of the referential expressions: ix d(x), any x d(x) or all x d(x).

Example

Agent i requests agent j and its federating other brokerage agents to do brokering a video-on-demand server agent to obtain "SF" programs.

(propagate

  :sender i

  :receiver j
  :content

    ((iota ?x

      (registered

        (:agent-description
          (:name ?x)

          (:service-description
            (:service-name agent-brokerage)))))
          (proxy

            :content

              ((iota ?y

                (registered

                  (:agent-description
                    (:name ?y)

                    (:service-description
                      (:service-name video-on-demand)))))
          (request

            :content

              (action

                (send-program
                  (:category "SF")))
                   :ontology vod-server-ontology
                   :protocol fipa-reqest …)
                   true)
                :ontology brokerage-agent-ontology
                :conversation-id vod-brokering-2
                :protocol fipa-brokering …)
                (hop-limit 5))
  :ontology brokerage-agent-ontology
  :hop-count 1 …)