Browse Prior Art Database

Protocol Exchange Algorithm for Client Server

IP.com Disclosure Number: IPCOM000111675D
Original Publication Date: 1994-Mar-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 8 page(s) / 216K

Publishing Venue

IBM

Related People

Wong, FC: AUTHOR

Abstract

An algorithm is described which generalizes the design of protocol conversion for the client/server environment. The two protocols being used for data transfer can be a combination of full and half duplex because the algorithm governs the conversation by a pseudo-communication state. Typically, the implementation of the algorithm is a router that communicates on one end with facility 'A' and on the other end with facility 'B' through which data is passed without being processed by the router itself.

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This is the abbreviated version, containing approximately 26% of the total text.

Protocol Exchange Algorithm for Client Server

      An algorithm is described which generalizes the design of
protocol conversion for the client/server environment.  The two
protocols being used for data transfer can be a combination of full
and half duplex because the algorithm governs the conversation by a
pseudo-communication state.  Typically, the implementation of the
algorithm is a router that communicates on one end with facility 'A'
and on the other end with facility 'B' through which data is passed
without being processed by the router itself.

      Most communication protocols use states to govern the sequence
of acceptable events.  For full duplex protocols, these communication
states may not exist.  The algorithm creates an internal
communication states such that its implementation can always
synchronize a conversation.  Assuming an implementation called the
Router, Fig. 1 shows the internal communication states:

    Internal States :

    =================

    RN - The Router has just been initiated and logged onto
         communication facility 'A', and is capable to receive data

    RC - The Router has logged onto the communication facility 'B'

    RS - Server connection made, or about to receive data from client

    RD1 - Received data from client but failed to connect to server

    RD2 - Received data from client but server already disconnected

    SR - Router forwarding data from server to client

    SD - Error data sent to client informing server connection
dropped

    SN - Communication facility 'B' logged off and error information
         sent to client

    FS - Client disconnected normally or abnormally

    FR - Client disconnected abnormally

    FD - Both communication facility 'A' and 'B' connection dropped

    FN - The Router logged off communication facility 'B' and
         terminating

      The transition from one state to another is shown in Fig. 2.
The rules governing the transition are denoted as f.

      In normal operation, the Router spends all of its time between
the RS and SR states.  The other states are entered either during the
initiation of a conversation or when the conversation breaks due to
various different reasons.

      A normal conversation will go through the following states :
STATE S(RN)

This is the initial state of the Router when it is started.  The
communication states are:

o   Facility 'A' = Receive

o   Facility 'B' = Not-logged on yet

Possible new states:

o   S(RC) (TRANSITION RULE F1)

          The Router has logged onto the communication facility 'B'.
    It is also capable to receive data from communication facility
    'A'.

o   S(FN) (TRANSITION RULE F17)

    If receive data from facility 'A' failed, the connection to
    facility 'A' is also terminated.

STATE S(RC)

      The conversation between remote client and the Router is
established.  The communi...