An OSI transport port entity represents one end of a transport connection
   and maintains status information about that connection.  Although the
   connectionless transport protocol does not create transport connections,
   ports are still used to maintain status information.

1  –  Counters

     DUPLICATE PDUS RECEIVED

         Total number of all types of detected duplicate TPDUs received from the
         remote NSAP.  This attribute applies only to COTS.

     FAILED CHECKSUM

         Number of checksum failure events detected.

     PDUS RECEIVED

         Total number of all types of TPDUs received from the remote NSAP
         excluding detected duplicates.

     PDUS SENT

         Total number of all types of TPDUs sent to the remote NSAP excluding
         retransmissions.

     RETRANSMITTED PDUS

         Total number of all types of retransmitted TPDUs sent to the remote
         NSAP.

     TOTAL OCTETS RECEIVED

         Total number of octets of all types of TPDUs received from the remote
         NSAP, regardless of their disposition. This count includes detected
         duplicates.

     TOTAL OCTETS SENT

         Total number of octets of all types of TPDUs sent to the remote NSAP,
         including retransmissions.

     USER OCTETS RECEIVED

         Total number of user data octets received from the remote NSAP,
         including normal, expedited, connect, accept, and disconnect data. This
         count does not include duplicates such as data retransmitted by the
         remote NSAP.

     USER OCTETS SENT

         Total number of user data octets sent to the remote NSAP, including
         normal, expedited, connect, accept, and disconnect data.  This count
         does not include data retransmitted by the local NSAP.

     USER PDUS RECEIVED

         Total number of PDUs containing user data received from the remote
         NSAP, including normal, expedited, connect, accept, and disconnect
         data. This count does not include duplicates such as TPDUs
         retransmitted by the remote NSAP.

     USER PDUS SENT

         Total number of TPDUs containing user data sent to the remote NSAP,
         including normal, expedited, connect, accept, and disconnect data. This
         count does not include retransmitted TPDUs.

2  –  status

     ACKNOWLEDGMENT DELAY TIME

         Maximum amount of time, in seconds, that an AK TPDU is to be withheld.
         This attribute applies to protocol class 4 only.

     CHECKSUMS

         Indicates whether checksums are in use on the transport connection.
         This attribute is supported only for class 4 protocol.

     CLIENT

         Name designated by the port user when the port was opened. If DNA
         session control is being used, this is the name of the session control
         port being used.

     CONS TEMPLATE

         When operating over the CONS, the name of the X.25 Access module's
         template specified when establishing the underlying network connection.

     CR TIMEOUT

         Amount of time, in seconds, to wait for a response to a CR TPDU before
         assuming that the remote transport service provider will not respond.
         This attribute is valid for protocol classes 0 and 2 only.

     DIRECTION

         Indicates whether the port is open to initiate an outgoing connection,
         to receive an incoming connection, or is listening for incoming
         connection requests.

         INCOMING -  Transport connection initiated by remote transport service.

         LISTENING - Listening for incoming connection requests.

         OUTGOING -  Transport connection initiated by this transport service.

         UNKNOWN -   Port direction is not known.

     ER TIMEOUT

         Amount of time, in seconds, to wait for a response to an ER TPDU
         before disconnecting the network connection. This attribute is valid
         for protocol classes 0 and 2 only.

     EXPEDITED DATA

         Indicates whether the expedited data option is in use for the transport
         connection. This attribute is supported only for class 2 and class 4
         protocols.

     EXTENDED FORMAT

         Indicates whether the use of extended formats should be negotiated for
         a transport connection which operates the class 2 or 4 protocol.

     INACTIVITY TIME

         Time, in seconds, being used for the inactivity timer. This value is
         the product of multiplying the keepalive time by the inactivity
         factor architectural constant = 4.  This attribute is valid for
         protocol class 4 only.

     INITIAL RETRANSMIT TIME

         Time, in seconds, used for the retransmission timer when sending the
         first TPDU on the transport connection.   The value of this attribute
         is derived from the template used when the port was initialized. This
         attribute applies to COTS only.

     KEEPALIVE TIME

         Time, in seconds, being used for the window timer. The value of this
         attribute is derived from the template used when the port was
         initialized.  This attribute is valid for protocol class 4 only.

     LOCAL NSAP

         Local NSAP address being used for the transport connection.

     LOCAL REFERENCE

         Unique reference number assigned to the transport connection by the
         local transport service provider. This attribute applies to COTS only.

     LOCAL TRANSPORT SELECTOR

         Local transport selector for this port.

     MAXIMUM NSDU SIZE

         When operating over the CONS, the maximum NSDU size for transmitting
         and receiving buffers.  Expressed as a number of octets. This attribute
         is valid for CONS only.

     NEGOTIATED TPDU SIZE

         The TPDU size which was negotiated for this transport connection. This
         attribute applies to COTS only.

     NETWORK PORT

         Name of the network service port being used.

     NETWORK SERVICE

         Type of network service over which the transport connection is
         operating.  Attribute value derived from the template used when the
         port was initialized.

     PROTOCOL CLASS

         Protocol class operating on the transport connection. This attribute
         is not valid for CLTS.

     REMOTE IDENTIFIER

         Implementation identity and version of the remote NSAP. When present,
         this value is received in the identification of implementation
         parameter of the CR or CC TPDU.  This attribute applies to COTS only.

     REMOTE NSAP

         Remote NSAP address being used for the transport connection. This
         attribute applies to COTS only.

     REMOTE REFERENCE

         Reference number assigned to the transport connection by the remote
         transport service provider.  The value will be 0 if the transport
         connection is operating the class 0 protocol.  This attribute applies
         to COTS only.

     REMOTE TRANSPORT SELECTOR

         Remote transport selector that identifies the remote transport service
         user. This attribute applies to COTS only.

     REQUEST ACKNOWLEDGMENT

         Indicates whether request acknowledgment was negotiated for this
         transport connection. This attribute is valid for class 4 protocol only.

     RETRANSMIT THRESHOLD

         Number of times a TPDU requiring acknowledgment is to be retransmitted
         without acknowledgment before the transmission completes with an
         error. This attribute is valid for class 4 protocol only.

     ROUND-TRIP DELAY ESTIMATE

         Current estimate, in milliseconds, of the round-trip delay on the
         transport connection.   This attribute is valid for protocol class 4
         only.

     SEND IMPLEMENTATION ID

         Indicates whether the implementation id will be sent in the CR. It is
         always returned in the CC if it is present in the CR.

     SEND PREFERRED MAXIMUM tpdu SIZE

         Indicates whether the preferred maximum TPDU size parameter was sent
         in the CR or CC TPDU.

     SEND REQUEST ACKNOWLEDGMENT

         Indicates whether the request acknowledgment parameter was sent in the
         CR or CC TPDU.

     TYPE

         Indicates that the port is being used for the connection-oriented CO
         Transport protocol.

         CL - Connectionless transport service.
         CO - Connection-Oriented transport service.

     USE CLNS ERROR REPORTS

         When operating over CLNS, indicates whether the network Routing layer's
         error reporting facility should be used when performing connection
         establishment. This attribute applies to COTS only.