rfc1007.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

          request, reason code 128+2 (see p. 87 of IS 8073).

     e.   An implementation shall not propose Class 1 or Class 3 in
          response to a connect request carrying Class 1 or Class 3 as
          an alternative class of service.

     f.   An implementation which proposes Class 4 in a connect request
          need not accept a proposal for Class 2 from its peer if Class
          2 was not offered as an alternative in the connect request, or
          if operation is over a CLNS. Class 2 shall be accepted when
          proposed by the responding peer if it  was offered as an
          alternative in the connect request.

4.4.1.2   Extended formats.

     a.   An implementation shall always propose use of extended formats
          when either Class 4 or Class 2 is proposed in a connect
          request.

     b.   An implementation shall always accept the use of extended
          formats when so proposed in a received connect request.





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RFC 1007                                                       June 1987


4.4.1.3   Expedited data.

     a.   Use of expedited data is subject to negotiation by users of
          Transport Service.

     b.   Expedited data shall be supported in Class 2.

4.4.1.4   Maximum protocol data unit size.

   (The provisions of this paragraph are under consideration.)

4.4.1.5   Use of checksum.

   An implementation shall propose use of checksums consistent with the
   expected quality of service and security requirements.


     a.   Checksums should be used when operating with the IP on
          catenated networks.

     b.   Checksums should not be used if high performance is required,
          except when required by high error rates in the network
          service.

     c.   Checksums should always be used when any encryption is being
          used.

4.4.1.6   Protection parameters.

   Use of the security parameters is not defined in this supplement.

4.4.1.7   Use of flow control in Class 2.


     a.   An implementation shall always propose the use of flow control
          in Class 2 whenever Class 2 is proposed as either primary or
          alternative choice of service.

     b.   An implementation shall accept use of flow control in Class 2
          whenever negotiation to Class 2 occurs.


4.4.1.8  Service quality parameters.


     a.   Use of the service quality parameters in the CR and CC
          protocol data units is not defined except for the residual
          error rate parameter and the priority parameter.

     b.   Residual error rate (the use of this parameter is under
          consideration).



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RFC 1007                                                       June 1987


     c.   Priority (the use of this parameter is under consideration).

4.4.2   Parameters.

          This paragraph defines the values to be used in the CR and CC
          TPDUs.

4.4.2.1   Class 2 parameters.

4.4.2.1.1   Connect request (CR) protocol data unit.

4.4.2.1.1.1   Fixed part of header.


     a.   Connect request code: as in IS 8073.

     b.   Initial credit allocation: this field defines the number of
          TPDUs offered as initial credit by the connection initiator.
          Since the field is of length  4, the maximum credit that can
          be initially offered is limited to 15.  These TPDUs are
          constrained in length to the maximum size defined in the TPDU
          size field, listed below in Paragraph 4.4.2.1.1.2.

     c.   Destination reference: as in IS 8073.

     d.   Source reference: this reference shall be selected pursuant to
          the provisions of Paragraph 5.2.1.

     e.   Class and option: the class field shall take binary value
          0010; the option field shall take binary value 0010. (These
          values select Class 2, and the options of extended formats and
          flow control in Class 2.)


4.4.2.1.1.2   Variable part of header.


     a.   TSAP identifiers: the parameter values shall follow the
          conventions given in Paragraphs 5.1.1 and 5.1.2.

     b.   TPDU size: (The values to be used are under consideration.)

     c.   Version number: as in IS 8073.

     d.   Protection parameters: should not be used.

     e.   Checksum: shall not be used.

     f.   Additional options: this field shall take binary value 0001 if
          the initiating user has proposed the use of expedited data,
          and shall take value 0000 otherwise.



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RFC 1007                                                       June 1987


     g.   Alternative protocol classes: this field shall not be used
          unless Class 0 is to be proposed as an alternate class of
          operation.

     h.   Throughput: should not be used.

     i.   Residual error rate: should not be used.

     j.   Priority: (Use of this parameter is under consideration.)

     k.   Transit delay: should not be used.

4.4.2.1.1.3  User data.

   The CR TPDU shall not carry user data which has any requirement
   whatever for security protection.

4.4.2.1.2   Connect Confirm (CC) TPDU.

4.4.2.1.2.1   Fixed part of header.


     a.   Connect confirm code: as in IS 8073.

     b.   Initial credit allocation: same as Paragraph 4.4.2.1.1.1.

     c.   Destination reference: this reference shall be the "Source
          reference" number from the received CR TPDU.

     d.   Source reference: this reference shall be selected pursuant to
          the provisions of Paragraph 5.2.1.

     e.   Class and option: the class field shall take binary value 0010
          and the option field shall take binary value  0010 (selects
          Class 2 and options of extended formats and flow control in
          Class 2).


4.4.2.1.2.2   Variable part of header.


     a.   TSAP identifier(s): the parameter values shall follow the
          conventions given in Paragraphs 5.1.1 and 5.1.2.

     b.   b. TPDU size: (The values for this parameter are under
          consideration.)

     c.   Version number: as in  IS 8073.

     d.   Protection parameters: should not be used.




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RFC 1007                                                       June 1987


     e.   Checksum : shall not be used.

     f.   Additional options: This field shall take binary value 0001 if
          the responding transport entity has proposed the use of
          expedited data, and shall take binary value 0000 otherwise.

     g.   Alternative protocol classes: shall not be used.

     h.   Throughput: should not be used.

     i.   Residual error rate: should not be used.

     j.   Priority: (The use of this parameter is under consideration.)

     k.   Transit delay: should not be used.

4.4.2.1.2.3   User data.

     The CC TPDU shall not carry any data which has any requirement
     whatever for security protection.

4.4.2.2   Class 4 parameters.

4.4.2.2.1  Connect request (CR) TPDU.

4.4.2.2.1.1   Fixed part of header.


     a.   Connect request code: as in IS 8073.

     b.   Initial credit allocation: this field defines the number of
          TPDUs offered as initial credit by the connection initiator.
          Since the field is of length 4, the maximum credit that can be
          initially offered is limited to 15. These TPDUs are
          constrained in length to the maximum size defined in the TPDU
          size field, listed below in Paragraph 4.4.2.2.1.2.

     c.   Destination reference: as in  IS 8073.

     d.   Source reference: this reference shall be selected pursuant to
          the provisions of Paragaph 5.2.1.

     e.   Class and option: the class field shall take binary value
          0100; the option field shall take binary value 0010. (These
          values select Class 4, and the options  of extended formats
          and flow control in Class 2.  This latter option is ignored if
          the class negotiated is Class 2.)







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RFC 1007                                                       June 1987


4.4.2.2.1.2   Variable part of header.


     a.   TSAP identifiers: the parameter values shall follow the
          conventions given in Paragraphs 5.1.1 and 5.1.2.

     b.   PDU size: (The values for this parameter are under
          consideration.)

     c.   Version number: as in IS 8073.

     d.   Protection parameters: should not be used.

     e.   Checksum: if Class 4 has been selected, this parameter may be
          used.  If Class 2 (or Class) has been selected, this parameter
          shall not be used.

     f.   Additional options: this field shall take binary value 0001 if
          the initiating user has proposed the use of expedited data,
          and shall take binary value 0000 otherwise.

     g.   Alternative protocol classes: this field shall be used only if
          Class 2 (or Class 0) is to be proposed as an alternate class
          of operation, conformant to the conditions of Paragraph
          4.4.1.1.  If Class 2 is proposed, the field shall take binary
          value 00000010 (1 octet).

     h.   Acknowledge time:  should not be used.

     i.   Throughput: should not be used.

     j.   Residual error rate: (The use of this parameter is under
          consideration.)

     k.   Priority: (The use of this parameter is under consideration.)

     l.   Transit delay: should not be used.

4.4.2.2.1.3   User data.

     The CR TPDU shall not carry user data which has any requirement
     whatever for security protection.

4.4.2.2.2   Connect confirm (CC) TPDU.

4.4.2.2.2.1   Fixed part of header.

     a.   Connect confirm code: as in IS 8073.

     b.   Initial credit allocation: same as Paragraph 4.4.2.2.1.1.b.




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RFC 1007                                                       June 1987


     c.   Destination reference: this reference shall be the number in
          "Source reference" from the received CR TPDU.

     d.   Source reference: this reference shall be selected pursuant to
          the provisions of Paragraph 5.2.1.

     e.   Class and option: if Class 2 has been selected, then the class
          field shall take binary value 0010 and the option field shall
          take binary value 0010.  If Class 4 has been selected, then
          the class field shall take binary value 0100 and the option
          field shall take binary value 0010.

4.4.2.2.1.2  Variable part of header.