rfc1415.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

   between a pair of hosts utilizing the same file transfer protocol.

   The latter, more transparent method does not necessarily require that
   the user determine which gateway is most appropriate for their
   respective source-destination pair.  In fact, filestore service
   providers are registered using the address of a predetermined
   gateway.  With this approach, the user:

       1. Must be aware that a gateway is required to reach the
          destination FTP or FTAM host.

       2. Need not determine which gateway is most appropriate to
          access their ultimate destination host.

       3. Need not explicitly connect to the gateway prior to
          connecting to the destination FTP or FTAM host.

5. Gateway State Variables and Transitions

   As described, the FTP-FTAM gateway provides two sets of services:
   FTP-Initiated and FTAM-Initiated.  Each service has its own mutually
   exclusive set of state variables and transitions that
   deterministically define the actions of the gateway.  Gateway support
   for these state variables and transitions is required.

   For conciseness in this discussion, FTP-Initiated will be abbreviated
   with "FTP-I", and FTAM-Initiated will be abbreviated with "FTAM-I".

   Concerning error conditions, if a connection is dropped when the
   gateway is in any state other than FTP-I:Initial-State or FTAM-
   I:Initial-State, then the gateway will issue a fatal error message to
   the host with the remaining connection, and then drop that
   connection.  If the remaining host is an FTP Client, then the gateway
   will send an ABOR, QUIT, and 426 reply code (Connection closed,



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RFC 1415             FTP-FTAM Gateway Specification         January 1993


   transfer aborted).  If it is an FTAM Initiator, then the gateway will
   send an F-P-ABORT with a <Diagnostic> value with identifier 1011
   (Lower layer failure), as well as any known <Further Details>.

   Other error conditions are not addressed in this discussion.

5.1. FTP-Initiated Gateway Service

   The set of state variables for the FTP-Initiated Gateway service
   follow:

  State Variable                State Definition
  ----------------------------------------------------------------

  FTP-I:Initial-State           Initial state of FTP-Initiated Gateway
                                service.

                                Gateway is waiting for an FTP Client to
                                issue a USER command in order to
                                proceed with connection establishment
                                with remote FTAM Responder.  If SITE or
                                ACCT commands are sent while waiting
                                for USER command, save arguments for
                                subsequent use.

  FTP-I:Wait-for-PASS           Gateway has already received USER
                                command from FTP Client, as well as
                                userid and destination host DN.
                                Gateway is waiting for the FTAM
                                Responder logon password.

  FTP-I:Wait-for-PAddress       Gateway has already received PASS
                                command from FTP Client.  Gateway is
                                resolving the provided FTAM Responder's
                                address to a Presentation Address.  The
                                provided address may be a Distinguished
                                Name, User Friendly Name, or Domain
                                Name.  Resolution will typically be
                                done using X.500 directory services.

  FTP-I:Wait-for-Connection     Gateway has initiated a connection to
                                the FTAM Responder and is waiting for
                                notification as to whether or not the
                                logon is successful.

  FTP-I:Wait-for-ClientCmd      Connection exists between FTP Client
                                and FTAM Responder.  Gateway is waiting
                                for next command or response from FTP



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RFC 1415             FTP-FTAM Gateway Specification         January 1993


                                Client.  Commands and responses are
                                mapped as they are received.

  FTP-I:Wait-for-RespondrCmd    Connection exists between FTP Client
                                and FTAM Responder.  Gateway is waiting
                                for next command or response from FTAM
                                Responder.  Commands and responses are
                                mapped as they are received.

   Each of the possible state transitions is provided in the remainder
   of Section 5.1.  For each state transition, the actions causing the
   transition are listed.

5.1.1. FTP-I:Initial-State   -->   FTP-I:Initial-State

        1. Gateway receives SITE or ACCT command from FTP Client.
           SITE argument includes Distinguish Name of FTAM Responder.

5.1.2. FTP-I:Initial-State   -->   FTP-I:Wait-for-PASS

        1. Gateway receives USER command from FTP Client.  Arguments
           include Distinguished Name of FTAM Responder and userid on
           FTAM responder.

5.1.3. FTP-I:Wait-for-PASS   -->   FTP-I:Wait-for-PAddress

        1. Gateway receives PASS command from FTP Client.

5.1.4. FTP-I:Wait-for-PAddress   -->   FTP-I:Wait-for-Connection

        1. Gateway resolves received Distinguished Name, User Friendly
           Name, or Domain Name of FTAM Responder to OSI Presentation
           address.
        2. Gateway sends F-INITIALIZE to FTAM Responder with
           Presentation Address in <Called Presentation Address>,
           userid in <Initiator Identity>, and password in <Filestore
           Password>.

5.1.5. FTP-I:Wait-for-Connection   -->   FTP-I:Wait-for-NextMapping

        1. Gateway receives <State Result> of "Success" .
        2. Gateway sends 230 reply code (User Logged In) to FTP
           Client.

5.1.6. FTP-I:Wait-for-ClientCmd   -->   FTP-I:Wait-for-RespondrCmd

        1. Gateway receives command or response from FTP Client and
           maps it to FTAM protocol, as defined in section 8.1.



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RFC 1415             FTP-FTAM Gateway Specification         January 1993


5.1.7. FTP-I:Wait-for-RespondrCmd   -->   FTP-I:Wait-for-ClientCmd

        1. Gateway receives command or response from FTAM Responder
           and maps it to FTP protocol, as defined in section 8.1.

5.1.8. FTP-I:Wait-for-ClientCmd   -->   FTP-I:Wait-for-USER

        1. Gateway receives QUIT command from FTP Client; maps QUIT as
           per Section 8.1.

5.2. FTAM-Initiated Gateway Service

   The set of state variables for the FTAM-Initiated Gateway service
   follow:

  State Variable                State Definition
  ----------------------------------------------------------------

  FTAM-I:Initial-State          Initial state of FTAM-Initiated Gateway
                                Service.

                                Gateway is waiting for an FTAM
                                Initiator to issue an F-INITIALIZE
                                command in order to proceed with
                                connection establishment with remote
                                FTP Server.

  FTAM-I:Wait-for-IPAddress     Gateway has already received F-
                                INITIALIZE from FTAM Initiator.
                                Gateway is resolving the provided FTP
                                Server's address to an IP address.  The
                                provided address may be a Domain Name,
                                Distinguished Name, or User Friendly
                                Name.

  FTAM-I:Wait-for-Connection    Gateway has initiated a connection to
                                the FTP Server and is waiting for
                                notification as to whether or not the
                                logon is successful.

  FTAM-I:Wait-for-InitiatrCmd   Connection exists between FTAM
                                Initiator and FTP Server.  Gateway is
                                waiting for next command or response
                                from FTAM Initiator.  Commands and
                                responses are mapped as they are
                                received.





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RFC 1415             FTP-FTAM Gateway Specification         January 1993


  FTP-I:Wait-for-ServerCmd      Connection exists between FTAM
                                Initiator and FTP Server.  Gateway is
                                waiting for next command or response
                                from FTP Server.  Commands and
                                responses are mapped as they are
                                received.

   Each of the possible state transitions is provided in the remainder
   of Section 5.2.  For each state transition, the actions causing the
   transition are listed.

5.2.1. FTAM-I:Initial-State   -->   FTAM-I:Wait-for-IPAddress

        1. Gateway receives F-INITIALIZE from FTAM Initiator.  Domain
           Name of FTP Server is either in <Responding Presentation
           Address> or in the "@host" portion of the <Initiator
           Identity> parameter.  The userid is in <Initiator
           Identity>, and password is in <Filestore Password>
           parameter.

5.2.2. FTAM-I:Wait-for-IPAddress   -->   FTAM-I:Wait-for-Connection

        1. Gateway resolves received Domain Name, Distinguished Name,
           or User Friendly Name of FTP Server to IP address.
        2. Gateway sends USER to FTP Server.
        3. Gateway sends PASS to FTP Server.

5.2.3. FTAM-I:Wait-for-Connection  -->   FTAM-I:Wait-for-NextMapping

        1. Gateway receives 230 reply code (User Logged In) from FTP
           Server.
        2. Gateway sends <State Result> of "Success" to FTAM
           Initiator.

5.2.4  FTAM-I:Wait-for-InitiatrCmd   -->   FTAM-I:Wait-for-ServerCmd

        1. Gateway receives command or response from FTAM Initiator
           and maps it to FTP protocol, as defined in section 8.2.

5.2.5. FTAM-I:Wait-for-ServerCmd   -->   FTAM-I:Wait-for-InitiatrCmd

        1. Gateway receives command or response from FTP Server and
           maps it to FTAM protocol, as defined in section 8.2.

5.2.6. FTAM-I:Wait-for-InitiatrCmd  -->  FTAM-I:Wait-for-INITIALIZE

        1. Gateway receives F-CLOSE primitive from FTAM Initiator;
           maps F-CLOSE as per Section 8.2.



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RFC 1415             FTP-FTAM Gateway Specification         January 1993


6. Document Type Support

   The set of FTAM document types supported by the FTP-FTAM gateway is a
   subset of the document types identified in the Stable Implementation
   Agreements for Open Systems Interconnection Protocols:  Part 9 - FTAM
   Phase 2, produced by the March 1992 Open Systems Environment
   Implementors' Workshop [NIST92].  This subset was chosen for its
   equivalence to those document types supported by FTP.  The set
   includes:

                FTAM-1    "ISO FTAM Unstructured text file

                FTAM-3    "ISO FTAM Unstructured binary file

                NBS-9     "NBS-9 FTAM File directory file"

      FTAM document types map to FTP document types as follows:

                FTAM      <->       FTP
                ----------------------------------

                FTAM-1    <->       ASCII

                FTAM-3    <->       8 bit binary

                NBS-9     <->       Directory

   Gateway support for FTAM-1 and FTAM-2 is required, whereas support
   for NBS-9 is recommended.

6.1. Notes on NBS-9

   NBS-9 is optional in GOSIP versions 1 and 2 [NIST91].  NBS-9 will be
   superseded by its replacement when ISO/IEC ISP 10607-2 and ISO/IEC
   ISP 10607-2/Amendment 1 are published [NIST92].

   For conformance to NBS-9, an FTAM Responder is only required to
   return the <Filename> file attribute, subject to local security and
   access control.  All other requested attributes need not be returned.

   Systems supporting the NBS-9 document type shall make available an
   NBS-9 document called 'DIRLIS'.  This document can be used to obtain
   a listing of files and their associated attributes from a remote
   Filestore.







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RFC 1415             FTP-FTAM Gateway Specification         January 1993


7. Functional Comparison of FTP and FTAM

   A comprehensive comparison of the services offered by FTP and FTAM is
   beyond the scope of this specification.  What follows is an analysis
   of several key points.  Refer to [NIST 86a] and [ROSE90] for a more
   complete discourse on this topic.

   FTAM is not a superset of FTP; each protocol has functions that only
   it performs.  The set of FTAM functions is, however, larger than the
   set of FTP functions.

   FTP combines file management and file transfer into one protocol
   engine, whereas FTAM separates management and transfer as they relate
   to files.

   The file transfer services of both FTP and FTAM expect a reliable
   underlying end-to-end service.  At a minimum, this service includes
   the capability to transfer entire files between remote hosts and to
   display remote filenames.

   In addition to this basic file transfer service, FTAM supports the
   capability to:  access a few records from a file server, create a
   network file system (similar to Sun's Network File System), handle
   printing and spooling, and access remote database records.  FTP does