PeSIT partner interactions

This topic describes the interactions and processes that occur between partners when using the PeSIT protocol.

PeSIT provides a set of user services and a protocol dialog used by two partners to exchange files and messages. A service defines the interaction between two PeSIT end users.

Four types of service primitives implement this interaction:

Primitive Notation Description

Request

REQ

Request a given service

Indication

IND

Notify the arrival of a service request

Response

RSP

Answer a request

Confirmation

CNF

Confirm the arrival of a response to a previous request

At the very minimum, a service involves a request submitted by a user and its corresponding indication to the partner. Some services also require a response and a confirmation to be complete.

Send-file flows

The following table illustrates the communication flows between Initiator and Responder during file transmission.

Note A file exchange involves more than just sending a file's data. Control information also has to be conveyed before, during and after the data transfer. This extra information is contained in protocol messages called FPDU (File Protocol Data Unit).
Sending a file
  FPDU    

PeSIT

 

  

PeSIT

INITIATOR

 

  

RESPONDER

  

 

idle

  

F.CONNECT, REQ ------>

 

  

------>IND, F.CONNECT

F.CONNECT, CNF <------

 

  

<------RSP, F.CONNECT

  

 

connected

  

F.CREATE, REQ ------>

 

  

------>IND, F.CREATE

F.CREATE, CNF <------

 

  

<------RSP, F.CREATE

  

 

file selected

  

F.OPEN, REQ ------>

 

  

------>IND, F.OPEN

F.OPEN, CNF <------

 

  

<------RSP, F.OPEN

  

 

file opened

  

F.WRITE, REQ ------>

 

  

------>IND, F.WRITE

F.WRITE, CNF <------

 

  

<------RSP, F.WRITE

  

 

transfer started

  

F.DATA, REQ ------->

 

data transfer

------>IND, F.DATA

F.DATA, REQ ------->

 

  

------>IND, F.DATA

F.CHECK, REQ ------->

 

synchronization point

------>IND, F.CHECK

F.DATA, REQ ------->

 

  

------>IND, F.DATA

F.DATA, REQ ------->

 

  

------>IND, F.DATA

F.CHECK, REQ ------->

 

  

------>IND, F.CHECK

F.DATA, REQ ------->

 

  

------>IND, F.DATA

F.DATA-END, REQ ----->

 

  

------>IND, F.DATA-END

  

 

  

  

F.TRANSFER-END, REQ ----->

 

  

------>IND,F.TRANSFER-END

F.TRANSFER-END, CNF <-----

 

  

<------RSP,F.TRANSFER-END

  

 

transfer ended

  

F.CLOSE, REQ ------>

 

  

------>IND, F.CLOSE

F.CLOSE, CNF <------

 

  

<------RSP, F.CLOSE

  

 

file closed

  

F.DESELECT, REQ ------>

 

  

------>IND, F.DESELECT

F.DESELECT, CNF <------

 

  

<------RSP, F.DESELECT

  

 

file deselected

  

F.RELEASED, REQ ------>

 

  

------>IND, F.RELEASED

F.RELEASED, CNF <------

 

  

<------RSP, F.RELEASED

  

 

disconnected

  

Receive-file flows

The following diagram illustrates the communication flows between Initiator and Responder during file reception.

Receiving a file

PeSIT

  

PeSIT

INITIATOR

  

RESPONDER

  

connected

  

F.SELECT, REQ ------>

  

------>IND, F.SELECT

F.SELECT, CNF <------

  

<------RSP, F.SELECT

  

file selected

  

F.OPEN, REQ ------>

  

------>IND, F.OPEN

F.OPEN, CNF <------

  

<------RSP, F.OPEN

  

file opened

  

F.READ, REQ ------>

  

------>IND, F.READ

F.READ, CNF <------

  

<------RSP, F.READ

  

transfer started

  

F.DATA, IND <------

  

<------REQ, F.DATA

F.DATA, IND <------

  

<------REQ, F.DATA

F.CHECK, IND <------

  

<------REQ, F.CHECK

F.DATA, IND <------

  

<------REQ, F.DATA

F.DATA, IND <------

  

<------REQ, F.DATA

F.CHECK, IND <------

  

<------REQ, F.CHECK

F.DATA, IND <------

  

<------REQ, F.DATA

F.DATA-END, IND

  

<------REQ, F.DATA-END

  

  

  

F.TRANSFER-END, REQ ----->

  

------>IND,F.TRANSFER-END

F.TRANSFER-END, CNF <-----

  

<------RSP,F.TRANSFER-END

  

transfer ended

  

F.CLOSE, REQ ------>

  

------>IND, F.CLOSE

F.CLOSE, CNF <------

  

<------RSP, F.CLOSE

  

file closed 

  

F.DESELECT, REQ ------>

  

------>IND, F.DESELECT

F.DESELECT, CNF <------

  

<------RSP, F.DESELECT

  

file deselected

  

Send-message flows

The following interaction illustrates the communication flows between Initiator and Responder during message transmission.

Sending a message

PeSIT

  

PeSIT

INITIATOR

  

RESPONDER

  

idle

  

F.CONNECT, REQ ------>

  

------>IND, F.CONNECT

F.CONNECT, CNF <------

  

<------RSP, F.CONNECT

  

connected 

  

F.MESSAGE, REQ ------>

  

------>IND, F.MESSAGE

F.MESSAGE, CNF <------

  

<------RSP, F.MESSAGE

  

  

  

F.RELEASED, REQ ------>

  

------>IND, F.RELEASED

F.RELEASED, CNF <------

  

<------RSP, F.RELEASED

  

disconnected

  

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