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.
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 |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
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.
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
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".
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
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.
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.
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.
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.
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 |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
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
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:
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 |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
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
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.
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
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 |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
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".
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
6. Management Messages
6.1 Port Management Message
The Port Management message allows a port to be brought into service,
to be taken out of service, to be set to loop back, reset, or to
change the transmit data rate. Only the Bring Up and the Reset Input
Port functions change the connection state (established connections)
on the input port. Only the Bring Up function changes the value of
the Port Session Number. The Port Management message MAY also be
used for enabling the replace connection mechanism. The Port
Management message is also used as part of the Event Message flow
control mechanism.
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
operation has been completed. The Port Management Message is:
Message Type = 32
The Port Management message has the following format for the request
and success 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|x|x|x|x|x|x|x| Duration | Function |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Flags | Flow Control Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transmit Data Rate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
Event Sequence Number
The success response message gives the current value of the
Event Sequence Number of the switch port indicated by the Port
field. The Event Sequence Number is set to zero when the port
is initialised. It is incremented by one each time the port
detects an asynchronous event that the switch would normally
report via an Event message. If the Event Sequence Number in
the success response differs from the Event Sequence Number of
the most recent Event message received for that port, events
have occurred that were not reported via an Event message.
This is most likely to be due to the flow control that
restricts the rate at which a switch can send Event messages
for each port. In the request message this field is not used.
R: Connection Replace
The R flag shall only be checked when the Function field = 1
(Bring Up). If the R flag is set in the Port Management
request message, it indicates that a switch controller requests
the switch port to support the Connection Replace mechanism.
Connection Replace behaviour is described in chapter 4.2. If a
switch does not support the Connection Replace mechanism, it
MUST reply with the failure response: "45: Connection Replace
mechanism not supported on switch" and reset the R-flag. Upon
successful response, the R flag SHOULD remain set in the
response message.
Duration
Is the length of time in seconds, that any of the loopback
states remain in operation. When the duration has expired, the
port will automatically be returned to service. If another
Port Management message is received for the same port before
the duration has expired, the loopback will continue to remain
in operation for the length of time specified by the Duration
field in the new message. The Duration field is only used in
request messages with the Function field set to Internal
Loopback, External Loopback, or Bothway Loopback.
Function
Specifies the action to be taken. The specified action will be
taken regardless of the current status of the port (Available,
Unavailable, or any Loopback state). If the specified function
requires a new Port Session Number to be generated, the new
Port Session Number MUST be returned in the success response
message. The defined values of the Function field are:
Bring Up:
Function = 1. Bring the port into service. All connections
that originate at the specified input port MUST be deleted
and a new Port Session Number MUST be selected, preferably
using some form of random number. On completion of the
operation all dynamically assigned Label values for the
specified input port MUST be unassigned, i.e., no
connections will be established in the Label space that GSMP
controls on this input port. Afterwards, the Port Status of
the port will be Available.
Take Down:
Function = 2. Take the port out of service. Any data
received at this port will be discarded. No data will be
transmitted from this port. Afterwards, the Port Status of
the port will be Unavailable.