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RFC 3292

 
 
 

General Switch Management Protocol (GSMP) V3

Part 2 of 5, p. 18 to 47
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4.  Connection Management Messages

4.1  General Message Definitions

   Connection management messages are used by the controller to
   establish, delete, modify and verify connections across the switch.
   The Add Branch, Delete Tree, and Delete All connection management
   messages have the following format, for both request and response
   messages:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Reservation ID                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Input Port                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Input Service Selector                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Output Port                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Output Service Selector                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |IQS|OQS|P|x|N|O|              Adaptation Method                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                  Input Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                 Output Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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      When required, the Add Branch, Move Input Branch and Move Output
      Branch messages have an additional, variable length data block
      appended to the above message.  This will be required when
      indicated by the IQS and OQS flags (if the value of either is set
      to 0b10) and the service selector.  The additional data block has
      the following format:

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Input TC Flags|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                     Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Output TC Flags|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                     Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general messages will not be explained in
         this section.  Please refer to section 3.1 for details.

      Reservation ID
         Identifies the reservation that MUST be deployed for the branch
         being added.  Reservations are established using reservation
         management messages (see Chapter 5).  A value of zero indicates
         that no Reservation is being deployed for the branch.  If a
         reservation with a corresponding Reservation ID exists, then
         the reserved resources MUST be applied to the branch.  If the
         numerical value of Reservation ID is greater than the value of
         Max Reservations (from the Switch Configuration message), a
         failure response is returned indicating "20: Reservation ID out
         of Range".  If the value of Input Port differs from the input
         port specified in the reservation, or if the value of Output
         Port differs from the output port specified in the reservation,
         a failure response MUST be returned indicating "21: Mismatched
         reservation ports".  If no reservation corresponding to
         Reservation ID exists, a failure response MUST be returned
         indicating "23: Non-existent reservation ID".

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         If a valid Reservation ID is specified and the Service Model is
         used (i.e., IQS or OQS=0b10) then the Traffic Parameters Block
         may be omitted from the Add Branch message indicating that the
         Traffic Parameters specified in the corresponding Reservation
         Request message are to be used.

      Input Port
         Identifies a switch input port.

      Input Label
         Identifies an incoming labelled channel arriving at the switch
         input port indicated by the Input Port field.  The value in the
         Input Label field MUST be interpreted according to the Label
         Type attribute of the switch input port indicated by the Input
         Port field.

      Input Service Selector
         Identifies details of the service specification being used for
         the connection.  The interpretation depends upon the Input QoS
         Model Selector (IQS).

         IQS = 00: In this case, the Input Service Selector indicates a
                   simple priority.

         IQS = 01: In this case, the Input Service Selector is an opaque
                   service profile identifier.  The definition of these
                   service profiles is outside the scope of this
                   specification.  Service Profiles can be used to
                   indicate pre-defined Differentiated Service Per Hop
                   Behaviours.

         IQS = 10: In this case, the Input Service Selector corresponds
                   to a Service Spec as defined in Chapter 8.2.  When
                   the value of either IQS or OQS is set to 0b10, then a
                   Traffic Parameters Block is appended to the message.

         IQS = 11: In this case the Input Service Selector corresponds
                   to an ARM service specification.  Definition of ARM
                   service specifications is outside the scope of this
                   specification and is determined by the MType as
                   defined in Chapter 8.1.

      Output Port
         Identifies a switch output port.

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      Output Label
         Identifies an outgoing labelled channel departing at the switch
         output port indicated by the Output Port field.  The value in
         the Output Label field MUST be interpreted according to the
         Label Type attribute of the switch input port indicated by the
         Output Port field

      Output Service Selector
         Identifies details of the service model being used.  The
         interpretation depends upon the Output QoS Model selector
         (OQS).

         OQS = 00: In this case the Output Service Selector indicates a
                   simple priority.

         OQS = 01: In this case the Output Service Selector is an opaque
                   service profile identifier.  The definition of these
                   service profiles is outside the scope of this
                   specification.  Service Profiles can be used to
                   indicate pre-defined Differentiated Service Per Hop
                   Behaviours.

         OQS = 10: In this case the Output Service Selector corresponds
                   to a Service Spec as defined in Chapter 8.2.  When
                   the value of either IQS or OQS is set to 0b10 then a
                   Traffic Parameters Block is appended to the message.

         OQS = 11: In this case the Output Service Selector corresponds
                   to an ARM service specification.  Definition of ARM
                   service specifications is outside the scope of this
                   specification and is determined by the MType as
                   defined in Chapter 8.1.

      IQS, OQS
         Input and Output QoS Model Selector:
         The QoS Model Selector is used to specify a QoS Model for the
         connection.  The values of IQS and OQS determine respectively
         the interpretation of the Input Service Selector and the Output
         Service Selector, and SHOULD be interpreted as a priority, a
         QoS profile, a service specification, or an ARM specification
         as shown:

            IQS/OQS  QoS Model              Service Selector
            -------  ---------              ----------------
            00       Simple Abstract        Model Priority
            01       QoS Profile Model      QoS Profile
            10       Default Service Model  Service Specification
            11       Optional ARM           ARM Specification

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      P Flag
         If the Parameter flag is set it indicates that a single
         instance of the Traffic Parameter block is provided.  This
         occurs in cases where the Input Traffic Parameters are
         identical to Output Traffic Parameters.

      N Flag
         The Null flag is used to indicate a null adaptation method.
         This occurs when the branch is connecting two ports of the same
         type.

      O Flag
         The Opaque flag indicates whether the adaptation fields are
         opaque, or whether they are defined by the protocol.  See the
         definition of Adaptation Method below for further information.

      Adaptation Method
         The adaptation method is used to define the adaptation framing
         that may be in use when moving traffic from one port type to
         another port type; e.g., from a frame relay port to an ATM
         port.  The content of this field is defined by the Opaque flag.
         If the Opaque flag is set, then this field is defined by the
         switch manufacturer and is not defined in this protocol.  If
         the opaque flag is not set, the field is divided into two 12-
         bit fields as follows:

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |IQS|OQS|P|x|N|O|    Input Adaptation   |   Output Adaptation   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Input Adaptation
            Adaptation framing method used on incoming connections.

         Output Adaptation
            Adaptation framing method used on outgoing connections.

            Adaptation Types:

                  0x100                        PPP
                  0x200                        FRF.5
                  0x201                        FRF.8

      Input and Output TC Flags
         TC (Traffic Control) Flags are used in Add Branch, Move Input
         Branch and Move Output Branch messages for connections using
         the Service Model (i.e., when IQS or OQS=0b10).  The TC Flags
         field is defined in Section 10.6.

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      Input and Output Traffic Parameters Block
         This variable length field is used in Add Branch, Move Input
         Branch and Move Output Branch messages for connections using
         the Service Model (i.e., when IQS or OQS=0b10).  Traffic
         Parameters Block is defined in Section 10.5.  The Traffic
         Parameters Block may be omitted if a valid, non-zero
         Reservation ID is specified, in which case the Traffic
         Parameters of the corresponding Reservation Request message are
         used.  If the P flag is set, then the appended message block
         will only include a single traffic parameter block which will
         be used for both input and output traffic.

   For all connection management messages, except the Delete Branches
   message, the success response message is a copy of the request
   message returned with the Result field indicating success.  The Code
   field is not used in a connection management success response
   message.

   The failure response message is a copy of the request message
   returned with a Result field indicating failure.

   Fundamentally, no distinction is made between point-to-point and
   point-to-multipoint connections.  By default, the first Add Branch
   message for a particular Input Port and Input Label will establish a
   point-to-point connection.  The second Add Branch message with the
   same Input Port and Input Label fields will convert the connection to
   a point-to-multipoint connection with two branches.  However, to
   avoid possible inefficiency with some switch designs, the Multicast
   Flag is provided.  If the controller knows that a new connection is
   point-to-multipoint when establishing the first branch, it may
   indicate this in the Multicast Flag.  Subsequent Add Branch messages
   with the same Input Port and Input Label fields will add further
   branches to the point-to-multipoint connection.  Use of the Delete
   Branch message on a point-to-multipoint connection with two branches
   will result in a point-to-point connection.  However, the switch may
   structure this connection as a point-to-multipoint connection with a
   single output branch if it chooses.  (For some switch designs this
   structure may be more convenient.)  Use of the Delete Branch message
   on a point-to-point connection will delete the point-to-point
   connection.  There is no concept of a connection with zero output
   branches.  All connections are unidirectional, one input labelled
   channel to one or more output labelled channels.

   In GSMP a multipoint-to-point connection is specified by establishing
   multiple point-to-point connections, each of them specifying the same
   output branch.  (An output branch is specified by an output port and
   output label.)

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   The connection management messages may be issued regardless of the
   Port Status of the switch port.  Connections may be established or
   deleted when a switch port is in the Available, Unavailable, or any
   of the Loopback states.  However, all connection states on an input
   port will be deleted when the port returns to the Available state
   from any other state, i.e., when a Port Management message is
   received for that port with the Function field indicating either
   Bring Up, or Reset Input Port.

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4.2  Add Branch Message

   The Add Branch message is a connection management message used to
   establish a connection or to add an additional branch to an existing
   connection.  It may also be used to check the connection state stored
   in the switch.  The connection is specified by the Input Port and
   Input Label fields.  The output branch is specified by the Output
   Port and Output Label fields.  The quality of service requirements of
   the connection are specified by the QoS Model Selector and Service
   Selector fields.  To request a connection the Add Branch message is:

      Message Type = 16

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Reservation ID                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Input Port                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Input Service Selector                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Output Port                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Output Service Selector                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |IQS|OQS|P|x|N|O|              Adaptation Method                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|M|B|                                                       |
   +-+-+-+-+                  Input Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|M|R|                                                       |
   +-+-+-+-+                 Output Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   When the value of either IQS or OQS is set to 0b10 then the following
   Traffic Parameters Block is appended to the above message:

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Input TC Flags |x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~               Input Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Output TC Flags|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~              Output Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general connection message will not be
         explained in this section.  Please refer to section 4.1 for
         details.

      M: Multicast
         Multicast flags are used as a hint for point-to-multipoint or
         multipoint-to-point connections in the Add Branch message.
         They are not used in any other connection management messages
         and in these messages they SHOULD be set to zero.  There are
         two instances of the M-bit in the Add Branch message; one for
         input branch specified by the Input Port and Input Label fields
         and one for the output branch specified by the Output Port and
         Output Label fields.  If set for the input branch (in front of
         Input Label field), it indicates that the connection is very
         likely to be a point-to-multipoint connection.  If zero, it
         indicates that this connection is very likely to be a point-
         to-point connection or is unknown.  If set for the output
         branch (in front of the Output Label field), it indicates that
         the connection is very likely to be a multipoint-to-point
         connection.  If zero, it indicates that this connection is very
         likely to be a point-to-point connection or is unknown.

         If M flags are set for input as well as output branches, it
         indicates that the connection is very likely to be a
         multipoint-to-multipoint connection.

         The Multicast flags are only used in the Add Branch message
         when establishing the first branch of a new connection.  It is
         not required to be set when establishing subsequent branches of
         a point-to-multipoint or a multipoint-to-point connection and

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         on such connections it SHOULD be ignored by the receiver.
         (Except in cases where the connection replace bit is enabled
         and set, the receipt of the second and subsequent Add Branch
         messages from the receiver indicates a point-to-multipoint or a
         multipoint-to-point connection.)  If it is known that this is
         the first branch of a point-to-multipoint or a multipoint-to-
         point connection, this flag SHOULD be set.  If it is unknown,
         or if it is known that the connection is point-to-point, this
         flag SHOULD be zero.  The use of the multicast flag is not
         mandatory and may be ignored by the switch.  If unused, the
         flags SHOULD be set to zero.  Some switches use a different
         data structure for multicast connections rather than for
         point-to-point connections.  These flags prevent the switch
         from setting up a point-to-point structure for the first branch
         of a multicast connection that MUST immediately be deleted and
         reconfigured as point-to-multipoint or multipoint-to-point when
         the second branch is established.

      B: Bi-directional
         The Bi-directional flag applies only to the Add Branch message.
         In all other Connection Management messages it is not used.  It
         may only be used when establishing a point-to-point connection.
         The Bi-directional flag in an Add Branch message, if set,
         requests that two unidirectional connections be established,
         one in the forward direction, and one in the reverse direction.
         It is equivalent to two Add Branch messages, one specifying the
         forward direction, and one specifying the reverse direction.
         The forward direction uses the values of Input Port, Input
         Label, Output Port and Output Label as specified in the Add
         Branch message.  The reverse direction is derived by exchanging
         the values specified in the Input Port and Input Label fields,
         with those of the Output Port and Output Label fields
         respectively.  Thus, a connection in the reverse direction
         originates at the input port specified by the Output Port
         field, on the label specified by the Output Label field.  It
         departs from the output port specified by the Input Port field,
         on the label specified by the Input Label field.

         The Bi-directional flag is simply a convenience to establish
         two unidirectional connections in opposite directions between
         the same two ports, with identical Labels, using a single Add
         Branch message.  In all future messages the two unidirectional
         connections MUST be handled separately.  There is no bi-
         directional delete message.  However, a single Delete Branches
         message with two Delete Branch Elements, one for the forward
         connection and one for the reverse, may be used.

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      R: Connection Replace
         The Connection Replace flag applies only to the Add Branch
         message and is not used in any other Connection Management
         messages.  The R flag is used in cases when creation of
         multipoint-to-point connections is undesirable (e.g., POTS
         applications where fan-in is meaningless).  If the R flag is
         set, the new connection replaces any existing connection if the
         label is already in use at the same Output Port.

         The Connection Replace mechanism allows a single Add Connection
         command to function as either a Move Branch message or a
         combination of Delete Branch/Add Branch messages.  This
         mechanism is provided to support existing 64k call handling
         applications, such as emulating 64k voice switches.

         The use of R flag is optional and MUST be pre-configured in the
         Port Management message [see section 6.1] to activate its use.
         The R flag MUST NOT be set if it is not pre-configured with the
         Port Management message.  The switch MUST then return a Failure
         Response message: "36:  Replace of connection is not activated
         on switch".  Information about whether the function is active
         or not, can be obtained by using the Port Configuration message
         [see section 8.2].

         The R flag MUST NOT be set if either the M flag or the B flag
         is set.  If a switch receives an Add connection request that
         has the R flag set with either the B or the M flag set, it MUST
         return a failure response message of: "37:  Connection
         replacement mode cannot be combined with Bi-directional or
         Multicast mode"

   If the connection specified by the Input Port and Input Label fields
   does not already exist, it MUST be established with the single output
   branch specified in the request message.  If the Bi-directional Flag
   in the Flags field is set, the reverse connection MUST also be
   established.  The output branch SHOULD have the QoS attributes
   specified by the Class of Service field.

   If the connection specified by the Input Port and Input Label fields
   already exists and the R flag is not set, but the specified output
   branch does not, the new output branch MUST be added.  The new output
   branch SHOULD have the QoS attributes specified by the Class of
   Service field.

   If the connection specified by the Input Port and Input Label fields
   already exists and the specified output branch also already exists,
   the QoS attributes of the connection, specified by the Class of
   Service field, if different from the request message, SHOULD be

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   changed to that in the request message.  A success response message
   MUST be sent if the Result field of the request message is "AckAll".
   This allows the controller to periodically reassert the state of a
   connection or to change its priority.  If the result field of the
   request message is "NoSuccessAck" a success response message SHOULD
   NOT be returned.  This may be used to reduce the traffic on the
   control link for messages that are reasserting a previously
   established state.  For messages that are reasserting a previously
   established state, the switch MUST always check that this state is
   correctly established in the switch hardware (i.e., the actual
   connection tables used to forward cells or frames).

   If the connection specified by the Input Port and Input Label fields
   already exists, and the Bi-directional Flag in the Flags field is
   set, a failure response MUST be returned indicating: "15:  Point-to-
   point bi-directional connection already exists".

   It should be noted that different switches support multicast in
   different ways.  There may be a limit to the total number of point-
   to-multipoint or multipoint-to-point connections certain switches can
   support, and possibly a limit on the maximum number of branches that
   a point-to-multipoint or multipoint-to-point connection may specify.
   Some switches also impose a limit on the number of different Label
   values that may be assigned e.g., to the output branches of a point-
   to-multipoint connection.  Many switches are incapable of supporting
   more than a single branch of any particular point-to-multipoint
   connection on the same output port.  Specific failure codes are
   defined for some of these conditions.

4.2.1  ATM specific procedures:

   To request an ATM virtual path connection the ATM Virtual Path
   Connection (VPC) Add Branch message is:

      Message Type = 26

   An ATM virtual path connection can only be established between ATM
   ports, i.e., ports with the "ATM" Label Type attribute.  If an ATM
   VPC Add Branch message is received and either the switch input port
   specified by the Input Port field or the switch output port specified
   by the Output Port field is not an ATM port, a failure response
   message MUST be returned indicating, "28: ATM Virtual path switching
   is not supported on non-ATM ports".

   If an ATM VPC Add Branch message is received and the switch input
   port specified by the Input Port field does not support virtual path
   switching, a failure response message MUST be returned indicating,
   "24: ATM virtual path switching is not supported on this input port".

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   If an ATM virtual path connection already exists on the virtual path
   specified by the Input Port and Input VPI fields, a failure response
   message MUST be returned, indicating "27:  Attempt to add an ATM
   virtual channel connection branch to an existing virtual path
   connection".  For the VPC Add Branch message, if a virtual channel
   connection already exists on any of the virtual channels within the
   virtual path specified by the Input Port and Input VPI fields, a
   failure response message MUST be returned indicating, "26: Attempt to
   add an ATM virtual path connection branch to an existing virtual
   channel connection".

4.3  Delete Tree Message

   The Delete Tree message is a Connection Management message used to
   delete an entire connection.  All remaining branches of the
   connection are deleted.  A connection is defined by the Input Port
   and the Input Label fields.  The Output Port and Output Label fields
   are not used in this message.  The Delete Tree message is:

      Message Type = 18

   If the Result field of the request message is "AckAll" a success
   response message MUST be sent upon successful deletion of the
   specified connection.  The success message MUST NOT be sent until the
   delete operation has been completed and if possible, not until all
   data on the connection, queued for transmission, has been
   transmitted.

4.4  Verify Tree Message

   The Verify Tree message has been removed from this version of GSMP.

      Message Type = 19

   If a request message is received with Message Type = 19, a failure
   response MUST be returned with the Code field indicating:

   "3: The specified request is not implemented on this switch.".

4.5  Delete All Input Port Message

   The Delete All Input Port message is a connection management message
   used to delete all connections on a switch input port.  All
   connections that originate at the specified input port MUST be
   deleted.  On completion of the operation all dynamically assigned
   Label values for the specified port MUST be unassigned, i.e., there
   MUST be no connections established in the Label space that GSMP
   controls on this port.  The Service Selectors, Output Port, Input

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   Label and Output Label fields are not used in this message.  The
   Delete All Input Port message is:

      Message Type = 20

   If the Result field of the request message is "AckAll", a success
   response message MUST be sent upon completion of the operation.  The
   success response message MUST NOT be sent until the operation has
   been completed.

   The following failure response messages may be returned to a Delete
   All Input Port request.

         3: The specified request is not implemented on this switch.

         4: One or more of the specified ports does not exist.

         5: Invalid Port Session Number.

   If any field in a Delete All Input Port message not covered by the
   above failure codes is invalid, a failure response MUST be returned
   indicating: "2: Invalid request message".  Else, the Delete All Input
   Port operation MUST be completed successfully and a success message
   returned.  No other failure messages are permitted.

4.6  Delete All Output Port Message

   The Delete All message is a connection management message used to
   delete all connections on a switch output port.  All connections that
   have the specified output port MUST be deleted.  On completion of the
   operation all dynamically assigned Label values for the specified
   port MUST be unassigned, i.e., there MUST be no connections
   established in the Label space that GSMP controls on this port.  The
   Service Selectors, Input Port, Input Label and Output Label fields
   are not used in this message.  The Delete All Output Port message is:

      Message Type = 21

   If the Result field of the request message is "AckAll", a success
   response message MUST be sent upon completion of the operation.  The
   success response message MUST NOT be sent until the operation has
   been completed.

   The following failure response messages may be returned to a Delete
   All Output Port request.

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         3: The specified request is not implemented on this switch.

         4: One or more of the specified ports does not exist.

         5: Invalid Port Session Number.

   If any field in a Delete All Output Port message not covered by the
   above failure codes is invalid, a failure response MUST be returned
   indicating: "2: Invalid request message".  Else, the delete all
   operation MUST be completed successfully and a success message
   returned.  No other failure messages are permitted.

4.7  Delete Branches Message

   The Delete Branches message is a connection management message used
   to request one or more delete branch operations.  Each delete branch
   operation deletes a branch of a channel, or in the case of the last
   branch of a connection, it deletes the connection.  The Delete
   Branches message is:

      Message Type = 17

   The request message has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|x|      Number of Elements       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                    Delete Branch Elements                     ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general connection message will not be
         explained in this section.  Please refer to section 4.1 for
         details.

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      Number of Elements
         Specifies the number of Delete Branch Elements to follow in the
         message.  The number of Delete Branch Elements in a Delete
         Branches message MUST NOT cause the packet length to exceed the
         maximum transmission unit defined by the encapsulation.

   Each Delete Branch Element specifies a branch to be deleted and has
   the following structure:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Error |x|x|x|x|x|x|x|x|x|x|x|x|       Element Length          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Input Port                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Output Port                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                  Input Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                 Output Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general connection message will not be
         explained in this section.  Please refer to section 4.1 for
         details.

      Error
         Is used to return a failure code indicating the reason for the
         failure of a specific Delete Branch Element in a Delete
         Branches failure response message.  The Error field is not used
         in the request message and MUST be set to zero.  A value of
         zero is used to indicate that the delete operation specified by
         this Delete Branch Element was successful.  Values for the
         other failure codes are specified in Section 12, "Failure
         Response Codes".

         All other fields of the Delete Branch Element have the same
         definition as specified for the other connection management
         messages.

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   In each Delete Branch Element, a connection is specified by the Input
   Port and Input Label fields.  The specific branch to be deleted is
   indicated by the Output Port and Output Label fields.

   If the Result field of the Delete Branches request message is
   "AckAll" a success response message MUST be sent upon successful
   deletion of the branches specified by all of the Delete Branch
   Elements.  The success response message MUST NOT be sent until all of
   the delete branch operations have been completed.  The success
   response message is only sent if all of the requested delete branch
   operations were successful.  No Delete Branch Elements are returned
   in a Delete Branches success response message and the Number of
   Elements field MUST be set to zero.

   If there is a failure in any of the Delete Branch Elements, a Delete
   Branches failure response message MUST be returned.  The Delete
   Branches failure response message is a copy of the request message
   with the Code field of the entire message set to "10: General Message
   Failure" and the Error field of each Delete Branch Element indicating
   the result of each requested delete operation.  A failure in any of
   the Delete Branch Elements MUST NOT interfere with the processing of
   any other Delete Branch Elements.

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4.8  Move Output Branch Message

   The Move Output Branch message is used to move a branch of an
   existing connection from its current output port label to a new
   output port label in a single atomic transaction.  The Move Output
   Branch connection management message has the following format for
   both request and response messages:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Input Port                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Input Service Selector                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Old Output Port                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        New Output Port                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Output Service Selector                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |IQS|OQS|P|x|N|O|             Adaptation Method                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                  Input Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+               Old Output Label                        |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                New Output Label                       |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   When the value of either IQS or OQS is set to 0b10 then the following
   Traffic Parameters Block is appended to the above message:

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Input TC Flags |x x x x x x x x x x x x x x x x x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~               Input Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Output TC Flags|x x x x x x x x x x x x x x x x x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~              Output Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general connection message will not be
         explained in this section.  Please refer to section 4.1 for
         details.

   The Move Output Branch message is a connection management message
   used to move a single output branch of connection from its current
   output port and Output Label, to a new output port and Output Label
   on the same connection.  None of the connection's other output
   branches are modified.  When the operation is complete the original
   Output Label on the original output port will be deleted from the
   connection.

   The Move Output Branch message is:

      Message Type = 22

   For the Move Output Branch message, if the connection specified by
   the Input Port and Input Label fields already exists, and the output
   branch specified by the Old Output Port and Old Output Label fields
   exists as a branch on that connection, the output branch specified by
   the New Output Port and New Output Label fields is added to the
   connection and the branch specified by the Old Output Port and Old
   Output Label fields is deleted.  If the Result field of the request
   message is "AckAll", a success response message MUST be sent upon
   successful completion of the operation.  The success response message
   MUST NOT be sent until the Move Branch operation has been completed.

   For the Move Output Branch message, if the connection specified by
   the Input Port and Input Label fields already exists, but the output
   branch specified by the Old Output Port and Old Output Label fields

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   does not exist as a branch on that connection, a failure response
   MUST be returned with the Code field indicating, "12: The specified
   branch does not exist".

4.8.1  ATM Specific Procedures:

   The ATM VPC Move Output Branch message is a connection management
   message used to move a single output branch of a virtual path
   connection from its current output port and output VPI, to a new
   output port and output VPI on the same virtual channel connection.
   None of the other output branches are modified.  When the operation
   is complete the original output VPI on the original output port will
   be deleted from the connection.

   The VPC Move Branch message is:

       Message Type = 27

   For the VPC Move Output Branch message, if the virtual path
   connection specified by the Input Port and Input VPI fields already
   exists, and the output branch specified by the Old Output Port and
   Old Output VPI fields exists as a branch on that connection, the
   output branch specified by the New Output Port and New Output VPI
   fields is added to the connection and the branch specified by the Old
   Output Port and Old Output VPI fields is deleted.  If the Result
   field of the request message is "AckAll", a success response message
   MUST be sent upon successful completion of the operation.  The
   success response message MUST NOT be sent until the Move Branch
   operation has been completed.

   For the VPC Move Output Branch message, if the virtual path
   connection specified by the Input Port and Input VPI fields already
   exists, but the output branch specified by the Old Output Port and
   Old Output VPI fields does not exist as a branch on that connection,
   a failure response MUST be returned with the Code field indicating,
   "12: The specified branch does not exist".

   If the virtual channel connection specified by the Input Port and
   Input Label fields; or the virtual path connection specified by the
   Input Port and Input VPI fields; does not exist, a failure response
   MUST be returned with the Code field indicating, "11: The specified
   connection does not exist".

   If the output branch specified by the New Output Port, New Output
   VPI, and New Output VCI fields for a virtual channel connection; or
   the output branch specified by the New Output Port and New Output VPI
   fields for a virtual path connection; is already in use by any
   connection other than that specified by the Input Port and Input

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   Label fields, then the resulting output branch will have multiple
   input branches.  If multiple point-to-point connections share the
   same output branch, the result will be a multipoint-to-point
   connection.  If multiple point-to-multipoint trees share the same
   output branches, the result will be a multipoint-to-multipoint
   connection.

4.9  Move Input Branch Message

   The Move Input Branch message is used to move a branch of an existing
   connection from its current input port label to a new input port
   label in a single atomic transaction.  The Move Input Branch
   connection management message has the following format for both
   request and response messages:

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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Output Port                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Input Service Selector                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Old Input Port                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        New Input Port                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Output Service Selector                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |IQS|OQS|P|x|N|O|             Adaptation Method                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                 Output Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                Old Input Label                        |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|x|x|                                                       |
   +-+-+-+-+                New Input Label                        |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   When the value of either IQS or OQS is set to 0b10, then the
   following Traffic Parameters Block is appended to the above message:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Input TC Flags |x x x x x x x x x x x x x x x x x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~               Input Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Output TC Flags|x x x x x x x x x x x x x x x x x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~              Output Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general connection message will not be
         explained in this section.  Please refer to section 4.1 for
         details.

   The Move Input Branch message is a connection management message used
   to move a single input branch of connection from its current input
   port and Input Label, to a new input port and Input Label on the same
   connection.  None of the connection's other input branches are
   modified.  When the operation is complete, the original Input Label
   on the original input port will be deleted from the connection.

   The Move Input Branch message is:

      Message Type = 23

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   For the Move Input Branch message, if the connection specified by the
   Output Port and Output Label fields already exists, and the input
   branch specified by the Old Input Port and Old Input Label fields
   exists as a branch on that connection, the input branch specified by
   the New Input Port and New Input Label fields is added to the
   connection and the branch specified by the Old Input Port and Old
   Input Label fields is deleted.  If the Result field of the request
   message is "AckAll", a success response message MUST be sent upon
   successful completion of the operation.  The success response message
   MUST NOT be sent until the Move Input Branch operation has been
   completed.

   For the Move Input Branch message, if the connection specified by the
   Output Port and Output Label fields already exists, but the input
   branch specified by the Old Input Port and Old Input Label fields
   does not exist as a branch on that connection, a failure response
   MUST be returned with the Code field indicating, "12: The specified
   branch does not exist".

4.9.1  ATM Specific Procedures:

   The ATM VPC Move Input Branch message is a connection management
   message used to move a single input branch of a virtual path
   connection from its current input port and input VPI, to a new input
   port and input VPI on the same virtual channel connection.  None of
   the other input branches are modified.  When the operation is
   complete, the original input VPI on the original input port will be
   deleted from the connection.

   The VPC Move Input Branch message is:

       Message Type = 28

   For the VPC Move Input Branch message, if the virtual path connection
   specified by the Output Port and Output VPI fields already exists,
   and the input branch specified by the Old Input Port and Old Input
   VPI fields exists as a branch on that connection, the input branch
   specified by the New Input Port and New Input VPI fields is added to
   the connection and the branch specified by the Old Input Port and Old
   Input VPI fields is deleted.  If the Result field of the request
   message is "AckAll" a success response message MUST be sent upon
   successful completion of the operation.  The success response message
   MUST NOT be sent until the Move Input Branch operation has been
   completed.

   For the VPC Move Input Branch message, if the virtual path connection
   specified by the Output Port and Output VPI fields already exists,
   but the input branch specified by the Old Input Port and Old Input

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   VPI fields does not exist as a branch on that connection, a failure
   response MUST be returned with the Code field indicating, "12: The
   specified branch does not exist".

   If the virtual channel connection specified by the Output Port and
   Output Label fields, or if the virtual path connection specified by
   the Output Port and Output VPI fields does not exist, a failure
   response MUST be returned with the Code field indicating, "11: The
   specified connection does not exist".

   If the input branch specified by the New Input Port, New Input VPI,
   and New Input VCI fields for a virtual channel connection, or the
   input branch specified by the New Input Port and New Input VPI fields
   for a virtual path connection, is already in use by any connection
   other than that specified by the Output Port and Output Label fields,
   then the resulting input branch will have multiple output branches.
   If multiple point-to-point connections share the same input branch,
   the result will be a point-to-multipoint connection.  If multiple
   multipoint-to-point trees share the same input branches, the result
   will be a multipoint-to-multipoint connection.

5.  Reservation Management Messages

   GSMP allows switch resources (e.g., bandwidth, buffers, queues,
   labels, etc.) to be reserved for connections before the connections
   themselves are established.  This is achieved through the
   manipulation of Reservations in the switch.

   Reservations are hard state objects in the switch that can be created
   by the controller by sending a Reservation Request message.  Each
   Reservation is uniquely identified by an identifying number called a
   Reservation ID.  Reservation objects can be deleted with the Delete
   Reservation message or the Delete All Reservations message.  A
   reservation object is also deleted when the Reservation is deployed
   by specifying a Reservation ID in a valid Add Branch message.

   The reserved resources MUST remain reserved until either the
   reservation is deployed, in which case the resources are applied to a
   branch, or the reservation is explicitly deleted (with a Delete
   Reservation message or a Delete All Reservations message), in which
   case the resources are freed.  Reservations and reserved resources
   are deleted if the switch is reset.

   A Reservation object includes its Reservation ID plus all the
   connection state associated with a branch with the exception that the
   branch's input label and/or output label may be unspecified.  The
   Request Reservation message is therefore almost identical to the Add
   Branch message.

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   The switch establishes the maximum number of reservations it can
   store by setting the value of Max Reservations in the Switch
   Configuration response message.  The switch indicates that it does
   not support reservations by setting Max Reservations to 0.  The valid
   range of Reservation IDs is 1 to Max Reservations).

5.1  Reservation Request Message

   The Reservation Request message creates a Reservation in the switch
   and reserves switch resources for a connection that may later be
   established using an Add Branch message.  The Reservation Request
   Message is:

      Message Type = 70

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   The Reservation Request message has the following format for the
   request message:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Reservation ID                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Input Port                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Input Service Selector                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Output Port                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Output Service Selector                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |IQS|OQS|P|x|N|O|             Adaptation Method                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|M|B|                                                       |
   +-+-+-+-+                  Input Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |x|S|M|x|                                                       |
   +-+-+-+-+                 Output Label                          |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   When the value of either IQS or OQS is set to 0b10 then the following
   Traffic Parameters Block is appended to the above message:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Input TC Flags |x x x x x x x x x x x x x x x x x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~               Input Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Output TC Flags|x x x x x x x x x x x x x x x x x x x x x x x x|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~              Output Traffic Parameters Block                  ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Note: Fields and Parameters that have been explained in the
         description of the general connection message will not be
         explained in this section.  Please refer to section 4.1 for
         details.

   All the fields of the Reservation Request message have the same
   meanings as they do in the Add Branch message with the following
   exceptions:

      Reservation ID
         Specifies the Reservation ID of the Reservation.  If the
         numerical value of the Reservation ID is greater than the value
         of the Max Reservations (from the Switch Configuration
         message), a failure response is returned indicating "20:  the
         Reservation ID out of Range".  If the value of Reservation ID
         matches that of an extant Reservation, a failure response is
         returned indicating "22: Reservation ID in use".

      Input Label
         If a specific input label is specified, then that label is
         reserved along with the required resources.  If the Input Label
         is 0 then the switch reserves the resources, but will not bind
         them to a label until the add branch command is given, which
         references the Reservation Id.  If the input label is 0, then
         all stacked labels MUST also be zeroed.

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      Output Label
         If a specific Output Label is specified then that label is
         reserved along with the required resources.  If the Output
         Label is 0 then the switch reserves the resources, but will not
         bind them to a label until the add branch command is given
         which references the Reservation Id.  If the Output Label is 0,
         then all stacked labels MUST also be zeroed

   When the switch receives a valid Reservation Request it reserves all
   the appropriate switch resources needed to establish a branch with
   corresponding attributes.  If sufficient resources are not available,
   a failure response is returned indicating "18: Insufficient
   resources".  Other failure responses are as defined for the Add
   Branch message.

5.2  Delete Reservation Message

   The Delete Reservation message deletes a Reservation object in the
   switch and frees the reserved switch resources associated with that
   reservation object.  The Reservation Request Message is:

      Message Type = 71

   The Delete Reservation message has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Port Session Number                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Reservation ID                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   If the Reservation ID matches that of an extant Reservation then the
   reservation is deleted and corresponding switch resources are freed.
   If the numerical value of the Reservation ID is greater than the
   value of the Max Reservations (from the Switch Configuration
   message), a failure response is returned indicating "20: Reservation
   ID out of Range".  If the value of Reservation ID does not match that
   of any extant Reservation, a failure response is returned indicating
   "23: Non-existent reservation ID".

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5.3  Delete All Reservations Message

   The Delete All Reservation message deletes all extant Reservation
   objects in the switch and frees the reserved switch resources of
   these reservations.  The Reservation Request Message is:

      Message Type = 72

   The Delete All Reservation message has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Version    | Message Type  |    Result     |     Code      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Partition ID  |            Transaction Identifier             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |I|      SubMessage Number      |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



(page 47 continued on part 3)

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