The MIB module for managing Media Gateways (MGs).
Terms used:
MG: Media Gateway
MGC: Media Gateway Controller
MGCP: Media Gateway Control Protocol
NE: Notified Entity
RSIP: Restart In Progress (MGCP standard message)
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (1..64) · OCTET STRING · hint 255t
Denotes name of the MG, as it is identified by media gateway controllers. This corresponds to a domain name under which the Media Gateway could also be registered in a DNS.
This object indicates the current admin state of the Media Gateway. The possible admin states are: 'inService' - The MG is ready to provide service. In this state, the MG will respond to connection control requests, emit autonomous messages to MGCs as applicable, etc. 'commandedOutOfService' - The MG does not provide service and all resources have been released. In this state, the MG will not respond to any connection control requests or emit autonomous messages. 'pendingOutOfService' - This is a transitional state prior to going 'commandedOutOfService'. In this state the MG provides service but does not accept new service requests (i.e. creation of connections) will transition to 'commandedOutOfService' according to 'mgShutdownGraceTime'.
This control object is used to change the service state of the MG from 'inService' to 'commandedOutOfService' and from 'commandedOutOfService' to 'inService'. The resulting service state of the gateway is represented by 'mgAdministrativeState'.
If set, this object triggers the following: 'inService': Transition 'mgAdministrativeState' to 'inService'. In the course, the MG's MGCs may get notified of this transition, e.g. in the case of MGCP through emission of RSIPs to registered call agents according to policy.
'forcefulOutOfService': Take the gateway out-of-service forcefully. This releases any resources at the MG. In the course, the MGCs may get notified of this transition, e.g. in the case of MGCP through emission of RSIPs to registered call agents according to policy.
'gracefulOutOfService': Take the gateway out-of-service gracefully. If there are no resources existing, 'mgAdministrative' transitions to 'commandedOutOfService' immediately. If resources exist, 'mgAdministrativeState' transitions to 'pendingOutOfService' thus initiating a graceful shutdown. In the course, the MGs MGCs may get notified of this transition, e.g. in the case of MGCP through emission of RSIPs to registered call agents according to policy.
mgShutdownGraceTime
1.3.6.1.4.1.351.150.10.1.1.4
Integer32 (-1..65535) · seconds
This object indicates the time in seconds after which an MG will transition from 'gracefulOutOfService' to 'forcefulOutOfService'. A value of -1 indicates that the MG allows for draining, i.e. will automatically transition after the last resource in use has been released. Otherwise, it essentially indicates the amount of time an MGC has to perform any cleanup, e.g. deletion of connections etc.
maxConcurrentMgcs
1.3.6.1.4.1.351.150.10.1.2.3
Unsigned32 (0..65535) · controllers
This object identifies the maximum number of MGCs the MG can have.
Identifies whether the MG creates endpoints for connections involving single channels (e.g. DS0s) dynamically upon receipt of a create connection request in the control protocol, or whether the endpoints have to be configured statically. This does not apply for endpoints involving several channels (such as nx64) which will in general be configured statically.
'dynamic': Endpoint created dynamically if not already existing. 'strictDynamic': Endpoint created dynamically; connection requests must not refer to preexisting endpoint. 'static': Endpoint statically provisioned.
This object will in general not be configurable, i.e. be read only in most agent implementations.
Table details
mgSupportedProtocolTable
1.3.6.1.4.1.351.150.10.1.1.7
Index: mgProtocolNumber
This is a table which identifies the protocols, along with their revisions that the media gateway supports for purposes of communication with an MGC. The table is created by the agent at system startup and cannot changed.
mgProtocolNumber
1.3.6.1.4.1.351.150.10.1.1.7.1.1
Integer32 (1..65535)
Serves as index to this table.
mgProtocolName
1.3.6.1.4.1.351.150.10.1.1.7.1.2
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (1..64) · OCTET STRING · hint 255t
A control protocol and its revision supported by the call gateway. For example: 'MGCP 0.1 11/9/99' The protocol can be one of the control protocols like MGCP or it can be a signaling backhaul protocol or it can be resource co-ordination protocol like SRCP.
mgcTable
1.3.6.1.4.1.351.150.10.1.2.1
Index: mgcNumber
This is a table which contains information about the individual MGCs.
mgcNumber
1.3.6.1.4.1.351.150.10.1.2.1.1.1
Integer32 (1..65535)
Serves as index to this table.
mgcName
1.3.6.1.4.1.351.150.10.1.2.1.1.2
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (1..64) · OCTET STRING · hint 255t
Denotes the name of the media gateway controller. This corresponds to a domain name under which the MGC could also be registered in a DNS. Once the row has become active, this value may not be modified.
mgcDnsResolution
1.3.6.1.4.1.351.150.10.1.2.1.1.3
TruthValue1 = true2 = falseRepresents a boolean value. · Integer32
Indicates how the MG resolves the IP address of the MGC. 'true(1)' - the resolution is done using an external DNS server.
'false(2)' - the resolution is done using
mgcResolutionTable.
Represents the state of the association between the MG and the MGC. The possible values are:
'mgcUnassociated' : MG and MGC are not associated. For example, in the case where MGCP is the coordination protocol, it means no subscription to autonomous messages such as RSIP but control requests would be answered.
'mgcAssociated' : MG and MGC are associated. E.g. in the
case where MGC is the coordination protocol, it means MGC is subscribed to autonomous messages such as RSIP. 'mgcAssociatedCommLoss' : Associated but MGC unreachable.
This object is being moved to the mgcRedundancyGrpParamTable. This object is deprecated because the association state is defined per MGC redundancy group, rather than per MGC.
Used to control the association state, as represented by mgcAssociationState. The possible value for a set operation on this object are: 'mgcUnassociate': Transition from any state to 'mgcUnassociated'. If registered, MG will initiate deregistration.
'mgcAssociate' : Transition to 'mgcAssociated'. If
applicable, MG will register with MGC. If MGCP is the coordination protocol, MG will send RSIP. If MG cannot establish communication, it will subsequently transition into 'mgcAssociatedCommLoss' for the 'mgcAssociationState' object. If MG is already associated with MGC, no transition will take place and mgcAssociationState shall not change.
'mgcClear' : No action will be taken. This means that the
Media Gateway will not initiate any association/unassociation.
This object is being moved to the mgcRedundancyGrpParamTable. This object is deprecated because the association state
control is defined per MGC redundancy group, rather
than per MGC.
mgcUnassociationPolicy
1.3.6.1.4.1.351.150.10.1.2.1.1.6
INTEGER1 = mgcNoAction2 = mgcRelease · Integer32
Indicates what MG will do when mgcAssociationState transitions to unassociated. 'mgcNoAction' : indicates that MG will take no further action. In particular, no resources will be released nor connections be flushed.
'mgcRelease' : indicates that upon unassociation, the
MG will release all resources and flush all connections.
This object may not always be configurable, i.e. be read only in some agent implementations. In these cases, mgcNoAction shall be supported as the default value.
mgcCommLossUnassociationTimeout
1.3.6.1.4.1.351.150.10.1.2.1.1.7
Integer32 (-1..65535) · seconds
Indicates how long, in seconds, upon detection of a communication loss, subscriptions to autonomous notifications (such as notification requests and RSIPs in the case of MGCP) remain valid and communications will be reattempted for an MGC in 'mgcAssociatedCommLoss' state.
A value of -1 indicates that the MGC may remain in 'mgcAssociatedCommLoss' state indefinitely. A value of 0 indicates that the MGC transitions into 'mgcUnassociated' state immediately.
This object may not always be configurable, i.e. be read only in some agent implementations. An MG implementation may not support differentiation of the timeout between associations. In such an event, any modification to the value for one MGC will take effect globally.
mgcRowStatus
1.3.6.1.4.1.351.150.10.1.2.1.1.8
RowStatus1 = active2 = notInService3 = notReady4 = createAndGo5 = createAndWait6 = destroyThe RowStatus textual convention is used to manage the creation and deletion of conceptual rows, and is used as the value of the SYNTAX clause for the status column of a conceptual row (as described in Section 7.7.1 of [2].)
The status column has six defined values:
- `active', which indicates that the conceptual row is available for use by the managed device;
- `notInService', which indicates that the conceptual row exists in the agent, but is unavailable for use by the managed device (see NOTE below); 'notInService' has no implication regarding the internal consistency of the row, availability of resources, or consistency with the current state of the managed device;
- `notReady', which indicates that the conceptual row exists in the agent, but is missing information necessary in order to be available for use by the managed device (i.e., one or more required columns in the conceptual row have not been instanciated);
- `createAndGo', which is supplied by a management station wishing to create a new instance of a conceptual row and to have its status automatically set to active, making it available for use by the managed device;
- `createAndWait', which is supplied by a management station wishing to create a new instance of a conceptual row (but not make it available for use by the managed device); and, - `destroy', which is supplied by a management station wishing to delete all of the instances associated with an existing conceptual row.
Whereas five of the six values (all except `notReady') may be specified in a management protocol set operation, only three values will be returned in response to a management
protocol retrieval operation: `notReady', `notInService' or
`active'. That is, when queried, an existing conceptual row
has only three states: it is either available for use by
the managed device (the status column has value `active'); it is not available for use by the managed device, though the agent has sufficient information to attempt to make it so (the status column has value `notInService'); or, it is not available for use by the managed device, and an attempt to make it so would fail because the agent has insufficient information (the state column has value `notReady').
NOTE WELL
This textual convention may be used for a MIB table, irrespective of whether the values of that table's conceptual rows are able to be modified while it is active, or whether its conceptual rows must be taken out of service in order to be modified. That is, it is the responsibility of the DESCRIPTION clause of the status column to specify whether the status column must not be `active' in order for the value of some other column of the same conceptual row to be modified. If such a specification is made, affected columns may be changed by an SNMP set PDU if the RowStatus would not be equal to `active' either immediately before or after processing the PDU. In other words, if the PDU also contained a varbind that would change the RowStatus value, the column in question may be changed if the RowStatus was not equal to `active' as the PDU was received, or if the varbind sets the status to a value other than 'active'.
Also note that whenever any elements of a row exist, the RowStatus column must also exist.
To summarize the effect of having a conceptual row with a status column having a SYNTAX clause value of RowStatus, consider the following state diagram:
STATE +--------------+-----------+-------------+-------------
| A | B | C | D
| |status col.|status column|
|status column | is | is |status column
ACTION |does not exist| notReady | notInService| is active
--------------+--------------+-----------+-------------+-------------
set status |noError ->D|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndGo |inconsistent- | | |
| Value| | |
--------------+--------------+-----------+-------------+-------------
set status |noError see 1|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndWait |wrongValue | | |
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError
column to | Value| entValue| |
active | | | |
| | or | |
| | | |
| |see 2 ->D|see 8 ->D| ->D
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError ->C
column to | Value| entValue| |
notInService | | | |
| | or | | or
| | | |
| |see 3 ->C| ->C|see 6
--------------+--------------+-----------+-------------+-------------
set status |noError |noError |noError |noError ->A
column to | | | | or
destroy | ->A| ->A| ->A|see 7
--------------+--------------+-----------+-------------+-------------
set any other |see 4 |noError |noError |see 5
column to some| | | |
value | | see 1| ->C| ->D
--------------+--------------+-----------+-------------+-------------
(1) goto B or C, depending on information available to the agent.
(2) if other variable bindings included in the same PDU, provide values for all columns which are missing but required, and all columns have acceptable values, then return noError and goto D.
(3) if other variable bindings included in the same PDU, provide legal values for all columns which are missing but required, then return noError and goto C.
(4) at the discretion of the agent, the return value may be either:
inconsistentName: because the agent does not choose to
create such an instance when the corresponding RowStatus instance does not exist, or
inconsistentValue: if the supplied value is
inconsistent with the state of some other MIB object's value, or
noError: because the agent chooses to create the instance.
If noError is returned, then the instance of the status column must also be created, and the new state is B or C, depending on the information available to the agent. If inconsistentName or inconsistentValue is returned, the row remains in state A.
(5) depending on the MIB definition for the column/table, either noError or inconsistentValue may be returned.
(6) the return value can indicate one of the following errors:
wrongValue: because the agent does not support notInService (e.g., an agent which does not support createAndWait), or
inconsistentValue: because the agent is unable to take the row out of service at this time, perhaps because it is in use and cannot be de-activated.
(7) the return value can indicate the following error:
inconsistentValue: because the agent is unable to remove the row at this time, perhaps because it is in use and cannot be de-activated.
(8) the transition to D can fail, e.g., if the values of the conceptual row are inconsistent, then the error code would be inconsistentValue.
NOTE: Other processing of (this and other varbinds of) the set request may result in a response other than noError being returned, e.g., wrongValue, noCreation, etc.
Conceptual Row Creation
There are four potential interactions when creating a
conceptual row: selecting an instance-identifier which is
not in use; creating the conceptual row; initializing any objects for which the agent does not supply a default; and, making the conceptual row available for use by the managed device.
Interaction 1: Selecting an Instance-Identifier
The algorithm used to select an instance-identifier varies for each conceptual row. In some cases, the instance- identifier is semantically significant, e.g., the destination address of a route, and a management station selects the instance-identifier according to the semantics.
In other cases, the instance-identifier is used solely to distinguish conceptual rows, and a management station without specific knowledge of the conceptual row might examine the instances present in order to determine an unused instance-identifier. (This approach may be used, but it is often highly sub-optimal; however, it is also a questionable practice for a naive management station to attempt conceptual row creation.)
Alternately, the MIB module which defines the conceptual row might provide one or more objects which provide assistance in determining an unused instance-identifier. For example, if the conceptual row is indexed by an integer-value, then an object having an integer-valued SYNTAX clause might be defined for such a purpose, allowing a management station to issue a management protocol retrieval operation. In order to avoid unnecessary collisions between competing management stations, `adjacent' retrievals of this object should be different.
Finally, the management station could select a pseudo-random number to use as the index. In the event that this index
was already in use and an inconsistentValue was returned in response to the management protocol set operation, the management station should simply select a new pseudo-random number and retry the operation.
A MIB designer should choose between the two latter algorithms based on the size of the table (and therefore the efficiency of each algorithm). For tables in which a large number of entries are expected, it is recommended that a MIB object be defined that returns an acceptable index for creation. For tables with small numbers of entries, it is recommended that the latter pseudo-random index mechanism be used.
Interaction 2: Creating the Conceptual Row
Once an unused instance-identifier has been selected, the management station determines if it wishes to create and activate the conceptual row in one transaction or in a negotiated set of interactions.
Interaction 2a: Creating and Activating the Conceptual Row
The management station must first determine the column requirements, i.e., it must determine those columns for which it must or must not provide values. Depending on the complexity of the table and the management station's knowledge of the agent's capabilities, this determination can be made locally by the management station. Alternately, the management station issues a management protocol get operation to examine all columns in the conceptual row that it wishes to create. In response, for each column, there are three possible outcomes:
- a value is returned, indicating that some other management station has already created this conceptual row. We return to interaction 1.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it should supply a value for this column when the conceptual row is to be created.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
Once the column requirements have been determined, a management protocol set operation is accordingly issued. This operation also sets the new instance of the status column to `createAndGo'.
When the agent processes the set operation, it verifies that it has sufficient information to make the conceptual row available for use by the managed device. The information
available to the agent is provided by two sources: the
management protocol set operation which creates the conceptual row, and, implementation-specific defaults supplied by the agent (note that an agent must provide implementation-specific defaults for at least those objects which it implements as read-only). If there is sufficient information available, then the conceptual row is created, a `noError' response is returned, the status column is set to `active', and no further interactions are necessary (i.e., interactions 3 and 4 are skipped). If there is insufficient information, then the conceptual row is not created, and the set operation fails with an error of `inconsistentValue'. On this error, the management station can issue a management protocol retrieval operation to determine if this was because it failed to specify a value for a required column, or, because the selected instance of the status column already existed. In the latter case, we return to interaction 1. In the former case, the management station can re-issue the set operation with the additional information, or begin interaction 2 again using `createAndWait' in order to negotiate creation of the conceptual row.
NOTE WELL
Regardless of the method used to determine the column requirements, it is possible that the management station might deem a column necessary when, in fact, the agent will not allow that particular columnar instance to be created or written. In this case, the management protocol set operation will fail with an error such as `noCreation' or `notWritable'. In this case, the management station decides whether it needs to be able to set a value for that particular columnar instance. If not, the management station re-issues the management protocol set operation, but without setting a value for that particular columnar instance; otherwise, the management station aborts the row creation algorithm.
Interaction 2b: Negotiating the Creation of the Conceptual Row
The management station issues a management protocol set operation which sets the desired instance of the status column to `createAndWait'. If the agent is unwilling to process a request of this sort, the set operation fails with an error of `wrongValue'. (As a consequence, such an agent must be prepared to accept a single management protocol set operation, i.e., interaction 2a above, containing all of the
columns indicated by its column requirements.) Otherwise,
the conceptual row is created, a `noError' response is returned, and the status column is immediately set to either `notInService' or `notReady', depending on whether it has sufficient information to (attempt to) make the conceptual row available for use by the managed device. If there is sufficient information available, then the status column is set to `notInService'; otherwise, if there is insufficient information, then the status column is set to `notReady'. Regardless, we proceed to interaction 3.
Interaction 3: Initializing non-defaulted Objects
The management station must now determine the column requirements. It issues a management protocol get operation to examine all columns in the created conceptual row. In the response, for each column, there are three possible outcomes:
- a value is returned, indicating that the agent implements the object-type associated with this column and had sufficient information to provide a value. For those columns to which the agent provides read-create access (and for which the agent allows their values to be changed after their creation), a value return tells the management station that it may issue additional management protocol set operations, if it desires, in order to change the value associated with this column.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. However, the agent does not have sufficient information to provide a value, and until a value is provided, the conceptual row may not be made available for use by the managed device. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it must issue additional management protocol set operations, in order to provide a value associated with this column.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
If the value associated with the status column is `notReady', then the management station must first deal with all `noSuchInstance' columns, if any. Having done so, the value of the status column becomes `notInService', and we proceed to interaction 4.
Interaction 4: Making the Conceptual Row Available
Once the management station is satisfied with the values associated with the columns of the conceptual row, it issues a management protocol set operation to set the status column to `active'. If the agent has sufficient information to make the conceptual row available for use by the managed device, the management protocol set operation succeeds (a `noError' response is returned). Otherwise, the management protocol set operation fails with an error of `inconsistentValue'.
NOTE WELL
A conceptual row having a status column with value `notInService' or `notReady' is unavailable to the managed device. As such, it is possible for the managed device to create its own instances during the time between the management protocol set operation which sets the status column to `createAndWait' and the management protocol set operation which sets the status column to `active'. In this case, when the management protocol set operation is issued to set the status column to `active', the values held in the agent supersede those used by the managed device.
If the management station is prevented from setting the status column to `active' (e.g., due to management station or network failure) the conceptual row will be left in the `notInService' or `notReady' state, consuming resources indefinitely. The agent must detect conceptual rows that have been in either state for an abnormally long period of time and remove them. It is the responsibility of the DESCRIPTION clause of the status column to indicate what an abnormally long period of time would be. This period of time should be long enough to allow for human response time (including `think time') between the creation of the conceptual row and the setting of the status to `active'. In the absence of such information in the DESCRIPTION clause, it is suggested that this period be approximately 5 minutes in length. This removal action applies not only to newly-created rows, but also to previously active rows which are set to, and left in, the notInService state for a prolonged period exceeding that which is considered normal for such a conceptual row.
Conceptual Row Suspension
When a conceptual row is `active', the management station may issue a management protocol set operation which sets the instance of the status column to `notInService'. If the agent is unwilling to do so, the set operation fails with an error of `wrongValue' or `inconsistentValue'. Otherwise, the conceptual row is taken out of service, and a `noError' response is returned. It is the responsibility of the DESCRIPTION clause of the status column to indicate under what circumstances the status column should be taken out of service (e.g., in order for the value of some other column of the same conceptual row to be modified).
Conceptual Row Deletion
For deletion of conceptual rows, a management protocol set operation is issued which sets the instance of the status column to `destroy'. This request may be made regardless of the current value of the status column (e.g., it is possible to delete conceptual rows which are either `notReady',
`notInService' or `active'.) If the operation succeeds,
then all instances associated with the conceptual row are immediately removed. · Integer32
Controls the creation and deletion of a table entry.
An entry may be created using the 'createAndGo' option. When the row is successfully created, the RowStatus would be set to 'active' by the agent. An entry may be deleted by setting the RowStatus to 'destroy'. Other options such as `createAndWait', 'notInService', 'notReady' will not be used.
For creating the row, a value for mgcName must be provided. This mgcName should be already added in mgDomainName table and at least 1 IP should associated to this mgcName. To all other objects, defaults defined by the agent implementation may apply.
Deletion of a row with mgcAssociationState other than unassociated shall be rejected.
mgcProtocolTable
1.3.6.1.4.1.351.150.10.1.2.2
Index: mgcNumber · mgProtocolNumber
This table contains information about which protocols are being used in a particular association between the gateway and the MGCs.
Because there may be a number of different protocols in use for a particular control association between the gateway and an MGC, this information is kept in a separate table rather than being included in mgcTable. In effect, it constitutes a relationship between mgcTable and mgSupportedProtocolTable.
With support for multiple MGC redundancy groups, the protocols will be defined per MGC redundancy group rather than per MGC. A new table mgcRedundancyGrpProtocolTable is introduced.
mgcProtocolRowStatus
1.3.6.1.4.1.351.150.10.1.2.2.1.1
RowStatus1 = active2 = notInService3 = notReady4 = createAndGo5 = createAndWait6 = destroyThe RowStatus textual convention is used to manage the creation and deletion of conceptual rows, and is used as the value of the SYNTAX clause for the status column of a conceptual row (as described in Section 7.7.1 of [2].)
The status column has six defined values:
- `active', which indicates that the conceptual row is available for use by the managed device;
- `notInService', which indicates that the conceptual row exists in the agent, but is unavailable for use by the managed device (see NOTE below); 'notInService' has no implication regarding the internal consistency of the row, availability of resources, or consistency with the current state of the managed device;
- `notReady', which indicates that the conceptual row exists in the agent, but is missing information necessary in order to be available for use by the managed device (i.e., one or more required columns in the conceptual row have not been instanciated);
- `createAndGo', which is supplied by a management station wishing to create a new instance of a conceptual row and to have its status automatically set to active, making it available for use by the managed device;
- `createAndWait', which is supplied by a management station wishing to create a new instance of a conceptual row (but not make it available for use by the managed device); and, - `destroy', which is supplied by a management station wishing to delete all of the instances associated with an existing conceptual row.
Whereas five of the six values (all except `notReady') may be specified in a management protocol set operation, only three values will be returned in response to a management
protocol retrieval operation: `notReady', `notInService' or
`active'. That is, when queried, an existing conceptual row
has only three states: it is either available for use by
the managed device (the status column has value `active'); it is not available for use by the managed device, though the agent has sufficient information to attempt to make it so (the status column has value `notInService'); or, it is not available for use by the managed device, and an attempt to make it so would fail because the agent has insufficient information (the state column has value `notReady').
NOTE WELL
This textual convention may be used for a MIB table, irrespective of whether the values of that table's conceptual rows are able to be modified while it is active, or whether its conceptual rows must be taken out of service in order to be modified. That is, it is the responsibility of the DESCRIPTION clause of the status column to specify whether the status column must not be `active' in order for the value of some other column of the same conceptual row to be modified. If such a specification is made, affected columns may be changed by an SNMP set PDU if the RowStatus would not be equal to `active' either immediately before or after processing the PDU. In other words, if the PDU also contained a varbind that would change the RowStatus value, the column in question may be changed if the RowStatus was not equal to `active' as the PDU was received, or if the varbind sets the status to a value other than 'active'.
Also note that whenever any elements of a row exist, the RowStatus column must also exist.
To summarize the effect of having a conceptual row with a status column having a SYNTAX clause value of RowStatus, consider the following state diagram:
STATE +--------------+-----------+-------------+-------------
| A | B | C | D
| |status col.|status column|
|status column | is | is |status column
ACTION |does not exist| notReady | notInService| is active
--------------+--------------+-----------+-------------+-------------
set status |noError ->D|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndGo |inconsistent- | | |
| Value| | |
--------------+--------------+-----------+-------------+-------------
set status |noError see 1|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndWait |wrongValue | | |
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError
column to | Value| entValue| |
active | | | |
| | or | |
| | | |
| |see 2 ->D|see 8 ->D| ->D
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError ->C
column to | Value| entValue| |
notInService | | | |
| | or | | or
| | | |
| |see 3 ->C| ->C|see 6
--------------+--------------+-----------+-------------+-------------
set status |noError |noError |noError |noError ->A
column to | | | | or
destroy | ->A| ->A| ->A|see 7
--------------+--------------+-----------+-------------+-------------
set any other |see 4 |noError |noError |see 5
column to some| | | |
value | | see 1| ->C| ->D
--------------+--------------+-----------+-------------+-------------
(1) goto B or C, depending on information available to the agent.
(2) if other variable bindings included in the same PDU, provide values for all columns which are missing but required, and all columns have acceptable values, then return noError and goto D.
(3) if other variable bindings included in the same PDU, provide legal values for all columns which are missing but required, then return noError and goto C.
(4) at the discretion of the agent, the return value may be either:
inconsistentName: because the agent does not choose to
create such an instance when the corresponding RowStatus instance does not exist, or
inconsistentValue: if the supplied value is
inconsistent with the state of some other MIB object's value, or
noError: because the agent chooses to create the instance.
If noError is returned, then the instance of the status column must also be created, and the new state is B or C, depending on the information available to the agent. If inconsistentName or inconsistentValue is returned, the row remains in state A.
(5) depending on the MIB definition for the column/table, either noError or inconsistentValue may be returned.
(6) the return value can indicate one of the following errors:
wrongValue: because the agent does not support notInService (e.g., an agent which does not support createAndWait), or
inconsistentValue: because the agent is unable to take the row out of service at this time, perhaps because it is in use and cannot be de-activated.
(7) the return value can indicate the following error:
inconsistentValue: because the agent is unable to remove the row at this time, perhaps because it is in use and cannot be de-activated.
(8) the transition to D can fail, e.g., if the values of the conceptual row are inconsistent, then the error code would be inconsistentValue.
NOTE: Other processing of (this and other varbinds of) the set request may result in a response other than noError being returned, e.g., wrongValue, noCreation, etc.
Conceptual Row Creation
There are four potential interactions when creating a
conceptual row: selecting an instance-identifier which is
not in use; creating the conceptual row; initializing any objects for which the agent does not supply a default; and, making the conceptual row available for use by the managed device.
Interaction 1: Selecting an Instance-Identifier
The algorithm used to select an instance-identifier varies for each conceptual row. In some cases, the instance- identifier is semantically significant, e.g., the destination address of a route, and a management station selects the instance-identifier according to the semantics.
In other cases, the instance-identifier is used solely to distinguish conceptual rows, and a management station without specific knowledge of the conceptual row might examine the instances present in order to determine an unused instance-identifier. (This approach may be used, but it is often highly sub-optimal; however, it is also a questionable practice for a naive management station to attempt conceptual row creation.)
Alternately, the MIB module which defines the conceptual row might provide one or more objects which provide assistance in determining an unused instance-identifier. For example, if the conceptual row is indexed by an integer-value, then an object having an integer-valued SYNTAX clause might be defined for such a purpose, allowing a management station to issue a management protocol retrieval operation. In order to avoid unnecessary collisions between competing management stations, `adjacent' retrievals of this object should be different.
Finally, the management station could select a pseudo-random number to use as the index. In the event that this index
was already in use and an inconsistentValue was returned in response to the management protocol set operation, the management station should simply select a new pseudo-random number and retry the operation.
A MIB designer should choose between the two latter algorithms based on the size of the table (and therefore the efficiency of each algorithm). For tables in which a large number of entries are expected, it is recommended that a MIB object be defined that returns an acceptable index for creation. For tables with small numbers of entries, it is recommended that the latter pseudo-random index mechanism be used.
Interaction 2: Creating the Conceptual Row
Once an unused instance-identifier has been selected, the management station determines if it wishes to create and activate the conceptual row in one transaction or in a negotiated set of interactions.
Interaction 2a: Creating and Activating the Conceptual Row
The management station must first determine the column requirements, i.e., it must determine those columns for which it must or must not provide values. Depending on the complexity of the table and the management station's knowledge of the agent's capabilities, this determination can be made locally by the management station. Alternately, the management station issues a management protocol get operation to examine all columns in the conceptual row that it wishes to create. In response, for each column, there are three possible outcomes:
- a value is returned, indicating that some other management station has already created this conceptual row. We return to interaction 1.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it should supply a value for this column when the conceptual row is to be created.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
Once the column requirements have been determined, a management protocol set operation is accordingly issued. This operation also sets the new instance of the status column to `createAndGo'.
When the agent processes the set operation, it verifies that it has sufficient information to make the conceptual row available for use by the managed device. The information
available to the agent is provided by two sources: the
management protocol set operation which creates the conceptual row, and, implementation-specific defaults supplied by the agent (note that an agent must provide implementation-specific defaults for at least those objects which it implements as read-only). If there is sufficient information available, then the conceptual row is created, a `noError' response is returned, the status column is set to `active', and no further interactions are necessary (i.e., interactions 3 and 4 are skipped). If there is insufficient information, then the conceptual row is not created, and the set operation fails with an error of `inconsistentValue'. On this error, the management station can issue a management protocol retrieval operation to determine if this was because it failed to specify a value for a required column, or, because the selected instance of the status column already existed. In the latter case, we return to interaction 1. In the former case, the management station can re-issue the set operation with the additional information, or begin interaction 2 again using `createAndWait' in order to negotiate creation of the conceptual row.
NOTE WELL
Regardless of the method used to determine the column requirements, it is possible that the management station might deem a column necessary when, in fact, the agent will not allow that particular columnar instance to be created or written. In this case, the management protocol set operation will fail with an error such as `noCreation' or `notWritable'. In this case, the management station decides whether it needs to be able to set a value for that particular columnar instance. If not, the management station re-issues the management protocol set operation, but without setting a value for that particular columnar instance; otherwise, the management station aborts the row creation algorithm.
Interaction 2b: Negotiating the Creation of the Conceptual Row
The management station issues a management protocol set operation which sets the desired instance of the status column to `createAndWait'. If the agent is unwilling to process a request of this sort, the set operation fails with an error of `wrongValue'. (As a consequence, such an agent must be prepared to accept a single management protocol set operation, i.e., interaction 2a above, containing all of the
columns indicated by its column requirements.) Otherwise,
the conceptual row is created, a `noError' response is returned, and the status column is immediately set to either `notInService' or `notReady', depending on whether it has sufficient information to (attempt to) make the conceptual row available for use by the managed device. If there is sufficient information available, then the status column is set to `notInService'; otherwise, if there is insufficient information, then the status column is set to `notReady'. Regardless, we proceed to interaction 3.
Interaction 3: Initializing non-defaulted Objects
The management station must now determine the column requirements. It issues a management protocol get operation to examine all columns in the created conceptual row. In the response, for each column, there are three possible outcomes:
- a value is returned, indicating that the agent implements the object-type associated with this column and had sufficient information to provide a value. For those columns to which the agent provides read-create access (and for which the agent allows their values to be changed after their creation), a value return tells the management station that it may issue additional management protocol set operations, if it desires, in order to change the value associated with this column.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. However, the agent does not have sufficient information to provide a value, and until a value is provided, the conceptual row may not be made available for use by the managed device. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it must issue additional management protocol set operations, in order to provide a value associated with this column.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
If the value associated with the status column is `notReady', then the management station must first deal with all `noSuchInstance' columns, if any. Having done so, the value of the status column becomes `notInService', and we proceed to interaction 4.
Interaction 4: Making the Conceptual Row Available
Once the management station is satisfied with the values associated with the columns of the conceptual row, it issues a management protocol set operation to set the status column to `active'. If the agent has sufficient information to make the conceptual row available for use by the managed device, the management protocol set operation succeeds (a `noError' response is returned). Otherwise, the management protocol set operation fails with an error of `inconsistentValue'.
NOTE WELL
A conceptual row having a status column with value `notInService' or `notReady' is unavailable to the managed device. As such, it is possible for the managed device to create its own instances during the time between the management protocol set operation which sets the status column to `createAndWait' and the management protocol set operation which sets the status column to `active'. In this case, when the management protocol set operation is issued to set the status column to `active', the values held in the agent supersede those used by the managed device.
If the management station is prevented from setting the status column to `active' (e.g., due to management station or network failure) the conceptual row will be left in the `notInService' or `notReady' state, consuming resources indefinitely. The agent must detect conceptual rows that have been in either state for an abnormally long period of time and remove them. It is the responsibility of the DESCRIPTION clause of the status column to indicate what an abnormally long period of time would be. This period of time should be long enough to allow for human response time (including `think time') between the creation of the conceptual row and the setting of the status to `active'. In the absence of such information in the DESCRIPTION clause, it is suggested that this period be approximately 5 minutes in length. This removal action applies not only to newly-created rows, but also to previously active rows which are set to, and left in, the notInService state for a prolonged period exceeding that which is considered normal for such a conceptual row.
Conceptual Row Suspension
When a conceptual row is `active', the management station may issue a management protocol set operation which sets the instance of the status column to `notInService'. If the agent is unwilling to do so, the set operation fails with an error of `wrongValue' or `inconsistentValue'. Otherwise, the conceptual row is taken out of service, and a `noError' response is returned. It is the responsibility of the DESCRIPTION clause of the status column to indicate under what circumstances the status column should be taken out of service (e.g., in order for the value of some other column of the same conceptual row to be modified).
Conceptual Row Deletion
For deletion of conceptual rows, a management protocol set operation is issued which sets the instance of the status column to `destroy'. This request may be made regardless of the current value of the status column (e.g., it is possible to delete conceptual rows which are either `notReady',
`notInService' or `active'.) If the operation succeeds,
then all instances associated with the conceptual row are immediately removed. · Integer32
Controls the creation and deletion of a table entry.
An entry may be created using the 'createAndGo' option. When the row is successfully created, the RowStatus would be set to 'active' by the agent. An entry may be deleted by setting the RowStatus to 'destroy'. Other options such as `createAndWait', 'notInService', 'notReady' will not be used.
With support for multiple MGC redundancy groups, the protocols will be defined per MGC redundancy group rather than per MGC.
mgEndpointTable
1.3.6.1.4.1.351.150.10.1.3.1
Index: mgEndpointNumber
This table contains information about the individual endpoints.
mgEndpointNumber
1.3.6.1.4.1.351.150.10.1.3.1.1.1
Integer32 (1..65535)
Identifies endpoint as it is known by the NE. The endpoint number is unique for the entire MG and ranges from 1 to the maximum number of endpoints that the MG can support.
mgEndpointLineNumber
1.3.6.1.4.1.351.150.10.1.3.1.1.2
Integer32 (1..65535)
Identifies the DS1 line. Generally, this will correspond to the ifIndex of the physical interface terminating the line.
Once the row has become active, this value may not be changed.
mgEndpointName
1.3.6.1.4.1.351.150.10.1.3.1.1.3
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (0..255) · OCTET STRING · hint 255t
Identifies endpoint as it is known by the MGC. If MG and MGC use a mutually agreed upon convention, this may be supplied by the agent, i.e. be read-only.
mgEndpointSpeed
1.3.6.1.4.1.351.150.10.1.3.1.1.4
Unsigned32 (0..65535) · Kbps
Indicates the endpoint's bandwidth, in Kbps. Typically, this will be 64 times the number of channels terminated by the endpoint.
Indicates the state of the endpoint. 'mgEndpointActive' - the endpoint is in service and operational. 'mgEndpointFailed' - the endpoint is in service but not operational, e.g. because a line that the endpoint belongs to is in a state of service affecting alarm. 'mgEndpointDegraded' - the endpoint is in service but not fully operational, e.g. in cases with endpoints with channels on multiple lines, when one of the lines is in a state of service affecting alarm
If MGCP is used as the control protocol, the following transitions will generally trigger an RSIP command: from 'mgEndpointActive'/'mgEndpointDegraded' to 'mgEndpointFailed' or from 'mgEndpointFailed' to 'mgEndpointDegraded'/'mgEndpointActive'. Transitions between 'mgEndpointActive' and 'mgEndpointDegraded' will generally not trigger emission of RSIP.
mgEndpointChannelMap
1.3.6.1.4.1.351.150.10.1.3.1.1.6
Integer32 (0..2147483647)
Bit map of DS0s used by the endpoint. Bit positions set to '1' represent DS0s used by the endpoint. The Bit position corresponds to the DS0 number.
Once the row has become active, this value may not be changed.
mgEndpointRowStatus
1.3.6.1.4.1.351.150.10.1.3.1.1.7
RowStatus1 = active2 = notInService3 = notReady4 = createAndGo5 = createAndWait6 = destroyThe RowStatus textual convention is used to manage the creation and deletion of conceptual rows, and is used as the value of the SYNTAX clause for the status column of a conceptual row (as described in Section 7.7.1 of [2].)
The status column has six defined values:
- `active', which indicates that the conceptual row is available for use by the managed device;
- `notInService', which indicates that the conceptual row exists in the agent, but is unavailable for use by the managed device (see NOTE below); 'notInService' has no implication regarding the internal consistency of the row, availability of resources, or consistency with the current state of the managed device;
- `notReady', which indicates that the conceptual row exists in the agent, but is missing information necessary in order to be available for use by the managed device (i.e., one or more required columns in the conceptual row have not been instanciated);
- `createAndGo', which is supplied by a management station wishing to create a new instance of a conceptual row and to have its status automatically set to active, making it available for use by the managed device;
- `createAndWait', which is supplied by a management station wishing to create a new instance of a conceptual row (but not make it available for use by the managed device); and, - `destroy', which is supplied by a management station wishing to delete all of the instances associated with an existing conceptual row.
Whereas five of the six values (all except `notReady') may be specified in a management protocol set operation, only three values will be returned in response to a management
protocol retrieval operation: `notReady', `notInService' or
`active'. That is, when queried, an existing conceptual row
has only three states: it is either available for use by
the managed device (the status column has value `active'); it is not available for use by the managed device, though the agent has sufficient information to attempt to make it so (the status column has value `notInService'); or, it is not available for use by the managed device, and an attempt to make it so would fail because the agent has insufficient information (the state column has value `notReady').
NOTE WELL
This textual convention may be used for a MIB table, irrespective of whether the values of that table's conceptual rows are able to be modified while it is active, or whether its conceptual rows must be taken out of service in order to be modified. That is, it is the responsibility of the DESCRIPTION clause of the status column to specify whether the status column must not be `active' in order for the value of some other column of the same conceptual row to be modified. If such a specification is made, affected columns may be changed by an SNMP set PDU if the RowStatus would not be equal to `active' either immediately before or after processing the PDU. In other words, if the PDU also contained a varbind that would change the RowStatus value, the column in question may be changed if the RowStatus was not equal to `active' as the PDU was received, or if the varbind sets the status to a value other than 'active'.
Also note that whenever any elements of a row exist, the RowStatus column must also exist.
To summarize the effect of having a conceptual row with a status column having a SYNTAX clause value of RowStatus, consider the following state diagram:
STATE +--------------+-----------+-------------+-------------
| A | B | C | D
| |status col.|status column|
|status column | is | is |status column
ACTION |does not exist| notReady | notInService| is active
--------------+--------------+-----------+-------------+-------------
set status |noError ->D|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndGo |inconsistent- | | |
| Value| | |
--------------+--------------+-----------+-------------+-------------
set status |noError see 1|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndWait |wrongValue | | |
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError
column to | Value| entValue| |
active | | | |
| | or | |
| | | |
| |see 2 ->D|see 8 ->D| ->D
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError ->C
column to | Value| entValue| |
notInService | | | |
| | or | | or
| | | |
| |see 3 ->C| ->C|see 6
--------------+--------------+-----------+-------------+-------------
set status |noError |noError |noError |noError ->A
column to | | | | or
destroy | ->A| ->A| ->A|see 7
--------------+--------------+-----------+-------------+-------------
set any other |see 4 |noError |noError |see 5
column to some| | | |
value | | see 1| ->C| ->D
--------------+--------------+-----------+-------------+-------------
(1) goto B or C, depending on information available to the agent.
(2) if other variable bindings included in the same PDU, provide values for all columns which are missing but required, and all columns have acceptable values, then return noError and goto D.
(3) if other variable bindings included in the same PDU, provide legal values for all columns which are missing but required, then return noError and goto C.
(4) at the discretion of the agent, the return value may be either:
inconsistentName: because the agent does not choose to
create such an instance when the corresponding RowStatus instance does not exist, or
inconsistentValue: if the supplied value is
inconsistent with the state of some other MIB object's value, or
noError: because the agent chooses to create the instance.
If noError is returned, then the instance of the status column must also be created, and the new state is B or C, depending on the information available to the agent. If inconsistentName or inconsistentValue is returned, the row remains in state A.
(5) depending on the MIB definition for the column/table, either noError or inconsistentValue may be returned.
(6) the return value can indicate one of the following errors:
wrongValue: because the agent does not support notInService (e.g., an agent which does not support createAndWait), or
inconsistentValue: because the agent is unable to take the row out of service at this time, perhaps because it is in use and cannot be de-activated.
(7) the return value can indicate the following error:
inconsistentValue: because the agent is unable to remove the row at this time, perhaps because it is in use and cannot be de-activated.
(8) the transition to D can fail, e.g., if the values of the conceptual row are inconsistent, then the error code would be inconsistentValue.
NOTE: Other processing of (this and other varbinds of) the set request may result in a response other than noError being returned, e.g., wrongValue, noCreation, etc.
Conceptual Row Creation
There are four potential interactions when creating a
conceptual row: selecting an instance-identifier which is
not in use; creating the conceptual row; initializing any objects for which the agent does not supply a default; and, making the conceptual row available for use by the managed device.
Interaction 1: Selecting an Instance-Identifier
The algorithm used to select an instance-identifier varies for each conceptual row. In some cases, the instance- identifier is semantically significant, e.g., the destination address of a route, and a management station selects the instance-identifier according to the semantics.
In other cases, the instance-identifier is used solely to distinguish conceptual rows, and a management station without specific knowledge of the conceptual row might examine the instances present in order to determine an unused instance-identifier. (This approach may be used, but it is often highly sub-optimal; however, it is also a questionable practice for a naive management station to attempt conceptual row creation.)
Alternately, the MIB module which defines the conceptual row might provide one or more objects which provide assistance in determining an unused instance-identifier. For example, if the conceptual row is indexed by an integer-value, then an object having an integer-valued SYNTAX clause might be defined for such a purpose, allowing a management station to issue a management protocol retrieval operation. In order to avoid unnecessary collisions between competing management stations, `adjacent' retrievals of this object should be different.
Finally, the management station could select a pseudo-random number to use as the index. In the event that this index
was already in use and an inconsistentValue was returned in response to the management protocol set operation, the management station should simply select a new pseudo-random number and retry the operation.
A MIB designer should choose between the two latter algorithms based on the size of the table (and therefore the efficiency of each algorithm). For tables in which a large number of entries are expected, it is recommended that a MIB object be defined that returns an acceptable index for creation. For tables with small numbers of entries, it is recommended that the latter pseudo-random index mechanism be used.
Interaction 2: Creating the Conceptual Row
Once an unused instance-identifier has been selected, the management station determines if it wishes to create and activate the conceptual row in one transaction or in a negotiated set of interactions.
Interaction 2a: Creating and Activating the Conceptual Row
The management station must first determine the column requirements, i.e., it must determine those columns for which it must or must not provide values. Depending on the complexity of the table and the management station's knowledge of the agent's capabilities, this determination can be made locally by the management station. Alternately, the management station issues a management protocol get operation to examine all columns in the conceptual row that it wishes to create. In response, for each column, there are three possible outcomes:
- a value is returned, indicating that some other management station has already created this conceptual row. We return to interaction 1.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it should supply a value for this column when the conceptual row is to be created.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
Once the column requirements have been determined, a management protocol set operation is accordingly issued. This operation also sets the new instance of the status column to `createAndGo'.
When the agent processes the set operation, it verifies that it has sufficient information to make the conceptual row available for use by the managed device. The information
available to the agent is provided by two sources: the
management protocol set operation which creates the conceptual row, and, implementation-specific defaults supplied by the agent (note that an agent must provide implementation-specific defaults for at least those objects which it implements as read-only). If there is sufficient information available, then the conceptual row is created, a `noError' response is returned, the status column is set to `active', and no further interactions are necessary (i.e., interactions 3 and 4 are skipped). If there is insufficient information, then the conceptual row is not created, and the set operation fails with an error of `inconsistentValue'. On this error, the management station can issue a management protocol retrieval operation to determine if this was because it failed to specify a value for a required column, or, because the selected instance of the status column already existed. In the latter case, we return to interaction 1. In the former case, the management station can re-issue the set operation with the additional information, or begin interaction 2 again using `createAndWait' in order to negotiate creation of the conceptual row.
NOTE WELL
Regardless of the method used to determine the column requirements, it is possible that the management station might deem a column necessary when, in fact, the agent will not allow that particular columnar instance to be created or written. In this case, the management protocol set operation will fail with an error such as `noCreation' or `notWritable'. In this case, the management station decides whether it needs to be able to set a value for that particular columnar instance. If not, the management station re-issues the management protocol set operation, but without setting a value for that particular columnar instance; otherwise, the management station aborts the row creation algorithm.
Interaction 2b: Negotiating the Creation of the Conceptual Row
The management station issues a management protocol set operation which sets the desired instance of the status column to `createAndWait'. If the agent is unwilling to process a request of this sort, the set operation fails with an error of `wrongValue'. (As a consequence, such an agent must be prepared to accept a single management protocol set operation, i.e., interaction 2a above, containing all of the
columns indicated by its column requirements.) Otherwise,
the conceptual row is created, a `noError' response is returned, and the status column is immediately set to either `notInService' or `notReady', depending on whether it has sufficient information to (attempt to) make the conceptual row available for use by the managed device. If there is sufficient information available, then the status column is set to `notInService'; otherwise, if there is insufficient information, then the status column is set to `notReady'. Regardless, we proceed to interaction 3.
Interaction 3: Initializing non-defaulted Objects
The management station must now determine the column requirements. It issues a management protocol get operation to examine all columns in the created conceptual row. In the response, for each column, there are three possible outcomes:
- a value is returned, indicating that the agent implements the object-type associated with this column and had sufficient information to provide a value. For those columns to which the agent provides read-create access (and for which the agent allows their values to be changed after their creation), a value return tells the management station that it may issue additional management protocol set operations, if it desires, in order to change the value associated with this column.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. However, the agent does not have sufficient information to provide a value, and until a value is provided, the conceptual row may not be made available for use by the managed device. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it must issue additional management protocol set operations, in order to provide a value associated with this column.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
If the value associated with the status column is `notReady', then the management station must first deal with all `noSuchInstance' columns, if any. Having done so, the value of the status column becomes `notInService', and we proceed to interaction 4.
Interaction 4: Making the Conceptual Row Available
Once the management station is satisfied with the values associated with the columns of the conceptual row, it issues a management protocol set operation to set the status column to `active'. If the agent has sufficient information to make the conceptual row available for use by the managed device, the management protocol set operation succeeds (a `noError' response is returned). Otherwise, the management protocol set operation fails with an error of `inconsistentValue'.
NOTE WELL
A conceptual row having a status column with value `notInService' or `notReady' is unavailable to the managed device. As such, it is possible for the managed device to create its own instances during the time between the management protocol set operation which sets the status column to `createAndWait' and the management protocol set operation which sets the status column to `active'. In this case, when the management protocol set operation is issued to set the status column to `active', the values held in the agent supersede those used by the managed device.
If the management station is prevented from setting the status column to `active' (e.g., due to management station or network failure) the conceptual row will be left in the `notInService' or `notReady' state, consuming resources indefinitely. The agent must detect conceptual rows that have been in either state for an abnormally long period of time and remove them. It is the responsibility of the DESCRIPTION clause of the status column to indicate what an abnormally long period of time would be. This period of time should be long enough to allow for human response time (including `think time') between the creation of the conceptual row and the setting of the status to `active'. In the absence of such information in the DESCRIPTION clause, it is suggested that this period be approximately 5 minutes in length. This removal action applies not only to newly-created rows, but also to previously active rows which are set to, and left in, the notInService state for a prolonged period exceeding that which is considered normal for such a conceptual row.
Conceptual Row Suspension
When a conceptual row is `active', the management station may issue a management protocol set operation which sets the instance of the status column to `notInService'. If the agent is unwilling to do so, the set operation fails with an error of `wrongValue' or `inconsistentValue'. Otherwise, the conceptual row is taken out of service, and a `noError' response is returned. It is the responsibility of the DESCRIPTION clause of the status column to indicate under what circumstances the status column should be taken out of service (e.g., in order for the value of some other column of the same conceptual row to be modified).
Conceptual Row Deletion
For deletion of conceptual rows, a management protocol set operation is issued which sets the instance of the status column to `destroy'. This request may be made regardless of the current value of the status column (e.g., it is possible to delete conceptual rows which are either `notReady',
`notInService' or `active'.) If the operation succeeds,
then all instances associated with the conceptual row are immediately removed. · Integer32
Controls the creation and deletion of a table entry.
An entry may be created using the 'createAndGo' option. When the row is successfully created, the RowStatus would be set to 'active' by the agent thereby creating an endpoint. An endpoint may be deleted by setting the RowStatus to 'destroy'. Other options such as `createAndWait', 'notInService', 'notReady' will not be used.
On creation, values for mgEndpointLineNumber and mgEndpointChannelMap have to be supplied.
This table extends the mgEndpointTable. Objects that do not directly describe the endpoint but extend the rules to configure the mgEndpointTable can be added to this table.
Each table entry describes an instance of an endpoint on a media gateway.
mgEndpointRepetition
1.3.6.1.4.1.351.150.10.1.3.3.1.1
Unsigned32
This object is used to create multiple rows in the mgEndpointTable as specified in the SNMP PDU, starting from the row specified by the index of the instance for the number of rows specified in this object.
The repetition operation will start from the mgEndpointNumber, mgEndpointLineNumber and mgEndpointChannelMap that is specified in the PDU and will add rows for the number specified in this object. If for a given mgEndpointLineNumber all the endpoints channels are exhausted, it will proceed to the next mgEndpointLineNumber. This will continue until the number of repetitions specified in this object is exhausted or the number of DS1s and endpoints is exhausted, whichever comes first.
The agent will need to be able to populate the objects in the mgEndpointTable with the appropriate values as new rows are created.
lineAssignmentTable
1.3.6.1.4.1.351.150.10.1.4.1
Index: lineNumber
This table contains information about each line in the media gateway.
lineNumber
1.3.6.1.4.1.351.150.10.1.4.1.1.1
Integer32 (1..65535)
Identifies the DS1 line. Generally, this will correspond to the ifIndex of the physical interface terminating the line.
channelAssignment
1.3.6.1.4.1.351.150.10.1.4.1.1.2
Integer32 (0..2147483647)
Each bit that is set represents that the corresponding DS0 is in use, either because it has been assigned to an endpoint or because it constitutes a signaling channel that is not available for assignment to an endpoint.
lineName
1.3.6.1.4.1.351.150.10.1.4.1.1.3
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (1..64) · OCTET STRING · hint 255t
Line name as identified by the MGC, if applicable. The default line name is 'LINE'. If MG uses a common convention, this may be supplied by the agent, i.e. be read-only.
mgcResolutionTable
1.3.6.1.4.1.351.150.10.1.5.1
Index: mgcResolutionIndex
This table provides the name to IP address mapping for each of the MGCs, external DNS server, tftp server and announcement server. It also stores the IP addresses of external resolved domain name. Several addresses may be associated with a single name.
mgcResolutionIndex
1.3.6.1.4.1.351.150.10.1.5.1.1.1
Integer32 (1..65535)
Serves as index to this table.
The table will be divided into two, index 1 to 88 will be used by the user and index 89 to 176 will be used by the VDNS to fill in the externally resolved IP address.
mgcResolutionName
1.3.6.1.4.1.351.150.10.1.5.1.1.2
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (1..64) · OCTET STRING · hint 255t
Denotes the name of the entity (MGC and/or NE) whose address is to be resolved. Once the row has become active, this value may not be changed.
mgcResolutionIpAddress
1.3.6.1.4.1.351.150.10.1.5.1.1.3
IpAddress SIZE (4)
Denotes the IP address of the entity. Once the row has become active, this value may not be changed. To change the IP address, an entry will have to be removed and a new entry will have to be added.
mgcResolutionCommState
1.3.6.1.4.1.351.150.10.1.5.1.1.4
INTEGER1 = csActive2 = csInactive · Integer32
Indicates whether the address is the one currently applied for communications with the system of that name. 'csActive' - name resolves to that IP address 'csInactive' - IP address currently not in use
On creation of the row, this value will be 'csInactive', although it may transition immediately to active, triggering the notification of 'mgcCommStateActive' specified in CISCO-VISM-TRAPS-MIB.
mgcResolutionPreference
1.3.6.1.4.1.351.150.10.1.5.1.1.5
Integer32 (1..65535)
This object can be used by the MG in the selection of an IP address if multiple IP addresses are available for the same name.
This object cannot be modified after this entry is created.
It has to be unique among various IP addresses of a same
domain name.
In which case the IP address associated with mgcResolutionPreference 1 would be selected over the IP address associated with mgcResolutionPreference 2.
mgcResolutionRowStatus
1.3.6.1.4.1.351.150.10.1.5.1.1.6
RowStatus1 = active2 = notInService3 = notReady4 = createAndGo5 = createAndWait6 = destroyThe RowStatus textual convention is used to manage the creation and deletion of conceptual rows, and is used as the value of the SYNTAX clause for the status column of a conceptual row (as described in Section 7.7.1 of [2].)
The status column has six defined values:
- `active', which indicates that the conceptual row is available for use by the managed device;
- `notInService', which indicates that the conceptual row exists in the agent, but is unavailable for use by the managed device (see NOTE below); 'notInService' has no implication regarding the internal consistency of the row, availability of resources, or consistency with the current state of the managed device;
- `notReady', which indicates that the conceptual row exists in the agent, but is missing information necessary in order to be available for use by the managed device (i.e., one or more required columns in the conceptual row have not been instanciated);
- `createAndGo', which is supplied by a management station wishing to create a new instance of a conceptual row and to have its status automatically set to active, making it available for use by the managed device;
- `createAndWait', which is supplied by a management station wishing to create a new instance of a conceptual row (but not make it available for use by the managed device); and, - `destroy', which is supplied by a management station wishing to delete all of the instances associated with an existing conceptual row.
Whereas five of the six values (all except `notReady') may be specified in a management protocol set operation, only three values will be returned in response to a management
protocol retrieval operation: `notReady', `notInService' or
`active'. That is, when queried, an existing conceptual row
has only three states: it is either available for use by
the managed device (the status column has value `active'); it is not available for use by the managed device, though the agent has sufficient information to attempt to make it so (the status column has value `notInService'); or, it is not available for use by the managed device, and an attempt to make it so would fail because the agent has insufficient information (the state column has value `notReady').
NOTE WELL
This textual convention may be used for a MIB table, irrespective of whether the values of that table's conceptual rows are able to be modified while it is active, or whether its conceptual rows must be taken out of service in order to be modified. That is, it is the responsibility of the DESCRIPTION clause of the status column to specify whether the status column must not be `active' in order for the value of some other column of the same conceptual row to be modified. If such a specification is made, affected columns may be changed by an SNMP set PDU if the RowStatus would not be equal to `active' either immediately before or after processing the PDU. In other words, if the PDU also contained a varbind that would change the RowStatus value, the column in question may be changed if the RowStatus was not equal to `active' as the PDU was received, or if the varbind sets the status to a value other than 'active'.
Also note that whenever any elements of a row exist, the RowStatus column must also exist.
To summarize the effect of having a conceptual row with a status column having a SYNTAX clause value of RowStatus, consider the following state diagram:
STATE +--------------+-----------+-------------+-------------
| A | B | C | D
| |status col.|status column|
|status column | is | is |status column
ACTION |does not exist| notReady | notInService| is active
--------------+--------------+-----------+-------------+-------------
set status |noError ->D|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndGo |inconsistent- | | |
| Value| | |
--------------+--------------+-----------+-------------+-------------
set status |noError see 1|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndWait |wrongValue | | |
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError
column to | Value| entValue| |
active | | | |
| | or | |
| | | |
| |see 2 ->D|see 8 ->D| ->D
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError ->C
column to | Value| entValue| |
notInService | | | |
| | or | | or
| | | |
| |see 3 ->C| ->C|see 6
--------------+--------------+-----------+-------------+-------------
set status |noError |noError |noError |noError ->A
column to | | | | or
destroy | ->A| ->A| ->A|see 7
--------------+--------------+-----------+-------------+-------------
set any other |see 4 |noError |noError |see 5
column to some| | | |
value | | see 1| ->C| ->D
--------------+--------------+-----------+-------------+-------------
(1) goto B or C, depending on information available to the agent.
(2) if other variable bindings included in the same PDU, provide values for all columns which are missing but required, and all columns have acceptable values, then return noError and goto D.
(3) if other variable bindings included in the same PDU, provide legal values for all columns which are missing but required, then return noError and goto C.
(4) at the discretion of the agent, the return value may be either:
inconsistentName: because the agent does not choose to
create such an instance when the corresponding RowStatus instance does not exist, or
inconsistentValue: if the supplied value is
inconsistent with the state of some other MIB object's value, or
noError: because the agent chooses to create the instance.
If noError is returned, then the instance of the status column must also be created, and the new state is B or C, depending on the information available to the agent. If inconsistentName or inconsistentValue is returned, the row remains in state A.
(5) depending on the MIB definition for the column/table, either noError or inconsistentValue may be returned.
(6) the return value can indicate one of the following errors:
wrongValue: because the agent does not support notInService (e.g., an agent which does not support createAndWait), or
inconsistentValue: because the agent is unable to take the row out of service at this time, perhaps because it is in use and cannot be de-activated.
(7) the return value can indicate the following error:
inconsistentValue: because the agent is unable to remove the row at this time, perhaps because it is in use and cannot be de-activated.
(8) the transition to D can fail, e.g., if the values of the conceptual row are inconsistent, then the error code would be inconsistentValue.
NOTE: Other processing of (this and other varbinds of) the set request may result in a response other than noError being returned, e.g., wrongValue, noCreation, etc.
Conceptual Row Creation
There are four potential interactions when creating a
conceptual row: selecting an instance-identifier which is
not in use; creating the conceptual row; initializing any objects for which the agent does not supply a default; and, making the conceptual row available for use by the managed device.
Interaction 1: Selecting an Instance-Identifier
The algorithm used to select an instance-identifier varies for each conceptual row. In some cases, the instance- identifier is semantically significant, e.g., the destination address of a route, and a management station selects the instance-identifier according to the semantics.
In other cases, the instance-identifier is used solely to distinguish conceptual rows, and a management station without specific knowledge of the conceptual row might examine the instances present in order to determine an unused instance-identifier. (This approach may be used, but it is often highly sub-optimal; however, it is also a questionable practice for a naive management station to attempt conceptual row creation.)
Alternately, the MIB module which defines the conceptual row might provide one or more objects which provide assistance in determining an unused instance-identifier. For example, if the conceptual row is indexed by an integer-value, then an object having an integer-valued SYNTAX clause might be defined for such a purpose, allowing a management station to issue a management protocol retrieval operation. In order to avoid unnecessary collisions between competing management stations, `adjacent' retrievals of this object should be different.
Finally, the management station could select a pseudo-random number to use as the index. In the event that this index
was already in use and an inconsistentValue was returned in response to the management protocol set operation, the management station should simply select a new pseudo-random number and retry the operation.
A MIB designer should choose between the two latter algorithms based on the size of the table (and therefore the efficiency of each algorithm). For tables in which a large number of entries are expected, it is recommended that a MIB object be defined that returns an acceptable index for creation. For tables with small numbers of entries, it is recommended that the latter pseudo-random index mechanism be used.
Interaction 2: Creating the Conceptual Row
Once an unused instance-identifier has been selected, the management station determines if it wishes to create and activate the conceptual row in one transaction or in a negotiated set of interactions.
Interaction 2a: Creating and Activating the Conceptual Row
The management station must first determine the column requirements, i.e., it must determine those columns for which it must or must not provide values. Depending on the complexity of the table and the management station's knowledge of the agent's capabilities, this determination can be made locally by the management station. Alternately, the management station issues a management protocol get operation to examine all columns in the conceptual row that it wishes to create. In response, for each column, there are three possible outcomes:
- a value is returned, indicating that some other management station has already created this conceptual row. We return to interaction 1.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it should supply a value for this column when the conceptual row is to be created.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
Once the column requirements have been determined, a management protocol set operation is accordingly issued. This operation also sets the new instance of the status column to `createAndGo'.
When the agent processes the set operation, it verifies that it has sufficient information to make the conceptual row available for use by the managed device. The information
available to the agent is provided by two sources: the
management protocol set operation which creates the conceptual row, and, implementation-specific defaults supplied by the agent (note that an agent must provide implementation-specific defaults for at least those objects which it implements as read-only). If there is sufficient information available, then the conceptual row is created, a `noError' response is returned, the status column is set to `active', and no further interactions are necessary (i.e., interactions 3 and 4 are skipped). If there is insufficient information, then the conceptual row is not created, and the set operation fails with an error of `inconsistentValue'. On this error, the management station can issue a management protocol retrieval operation to determine if this was because it failed to specify a value for a required column, or, because the selected instance of the status column already existed. In the latter case, we return to interaction 1. In the former case, the management station can re-issue the set operation with the additional information, or begin interaction 2 again using `createAndWait' in order to negotiate creation of the conceptual row.
NOTE WELL
Regardless of the method used to determine the column requirements, it is possible that the management station might deem a column necessary when, in fact, the agent will not allow that particular columnar instance to be created or written. In this case, the management protocol set operation will fail with an error such as `noCreation' or `notWritable'. In this case, the management station decides whether it needs to be able to set a value for that particular columnar instance. If not, the management station re-issues the management protocol set operation, but without setting a value for that particular columnar instance; otherwise, the management station aborts the row creation algorithm.
Interaction 2b: Negotiating the Creation of the Conceptual Row
The management station issues a management protocol set operation which sets the desired instance of the status column to `createAndWait'. If the agent is unwilling to process a request of this sort, the set operation fails with an error of `wrongValue'. (As a consequence, such an agent must be prepared to accept a single management protocol set operation, i.e., interaction 2a above, containing all of the
columns indicated by its column requirements.) Otherwise,
the conceptual row is created, a `noError' response is returned, and the status column is immediately set to either `notInService' or `notReady', depending on whether it has sufficient information to (attempt to) make the conceptual row available for use by the managed device. If there is sufficient information available, then the status column is set to `notInService'; otherwise, if there is insufficient information, then the status column is set to `notReady'. Regardless, we proceed to interaction 3.
Interaction 3: Initializing non-defaulted Objects
The management station must now determine the column requirements. It issues a management protocol get operation to examine all columns in the created conceptual row. In the response, for each column, there are three possible outcomes:
- a value is returned, indicating that the agent implements the object-type associated with this column and had sufficient information to provide a value. For those columns to which the agent provides read-create access (and for which the agent allows their values to be changed after their creation), a value return tells the management station that it may issue additional management protocol set operations, if it desires, in order to change the value associated with this column.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. However, the agent does not have sufficient information to provide a value, and until a value is provided, the conceptual row may not be made available for use by the managed device. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it must issue additional management protocol set operations, in order to provide a value associated with this column.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
If the value associated with the status column is `notReady', then the management station must first deal with all `noSuchInstance' columns, if any. Having done so, the value of the status column becomes `notInService', and we proceed to interaction 4.
Interaction 4: Making the Conceptual Row Available
Once the management station is satisfied with the values associated with the columns of the conceptual row, it issues a management protocol set operation to set the status column to `active'. If the agent has sufficient information to make the conceptual row available for use by the managed device, the management protocol set operation succeeds (a `noError' response is returned). Otherwise, the management protocol set operation fails with an error of `inconsistentValue'.
NOTE WELL
A conceptual row having a status column with value `notInService' or `notReady' is unavailable to the managed device. As such, it is possible for the managed device to create its own instances during the time between the management protocol set operation which sets the status column to `createAndWait' and the management protocol set operation which sets the status column to `active'. In this case, when the management protocol set operation is issued to set the status column to `active', the values held in the agent supersede those used by the managed device.
If the management station is prevented from setting the status column to `active' (e.g., due to management station or network failure) the conceptual row will be left in the `notInService' or `notReady' state, consuming resources indefinitely. The agent must detect conceptual rows that have been in either state for an abnormally long period of time and remove them. It is the responsibility of the DESCRIPTION clause of the status column to indicate what an abnormally long period of time would be. This period of time should be long enough to allow for human response time (including `think time') between the creation of the conceptual row and the setting of the status to `active'. In the absence of such information in the DESCRIPTION clause, it is suggested that this period be approximately 5 minutes in length. This removal action applies not only to newly-created rows, but also to previously active rows which are set to, and left in, the notInService state for a prolonged period exceeding that which is considered normal for such a conceptual row.
Conceptual Row Suspension
When a conceptual row is `active', the management station may issue a management protocol set operation which sets the instance of the status column to `notInService'. If the agent is unwilling to do so, the set operation fails with an error of `wrongValue' or `inconsistentValue'. Otherwise, the conceptual row is taken out of service, and a `noError' response is returned. It is the responsibility of the DESCRIPTION clause of the status column to indicate under what circumstances the status column should be taken out of service (e.g., in order for the value of some other column of the same conceptual row to be modified).
Conceptual Row Deletion
For deletion of conceptual rows, a management protocol set operation is issued which sets the instance of the status column to `destroy'. This request may be made regardless of the current value of the status column (e.g., it is possible to delete conceptual rows which are either `notReady',
`notInService' or `active'.) If the operation succeeds,
then all instances associated with the conceptual row are immediately removed. · Integer32
Controls the creation and deletion of a table entry.
An entry may be created using the 'createAndGo' option. mgcResolutionIndex, mgcResolutionName, mgcResolutionIpAddress, and mgcResolutionPreference should be provided when creating an entry. mgcResolutionIndex can be 1 - 88. Entries with index 89 - 176 will be implicitly added when VDNS resolves IP addresses of domain servers. Usually maximum 8 IP addresses can be added to one mgcName. For external DNS server only 3 IP addresses with the highest will be used. Before creating an entry in this table one entry should already been created in mgDomainNameTable with the same name as mgcResolutionName.
When the row is successfully created, the RowStatus would be set to 'active' by the agent.
An entry may be deleted by setting the RowStatus to 'destroy'. Only mgcResolutionIndex should be provided to delete an entry. The last IP within 1 - 88 should not be deleted if the mgcResolutionName is still configured for MGC, tftp server, external DNS server, PRI backhaul session group or announcement server and there is no external resolved IP (entry 89 - 176) for this domain name.
Other options such as `createAndWait', 'notInService', 'notReady' will not be used.
mgcDnsResolutionFlag
1.3.6.1.4.1.351.150.10.1.5.1.1.7
INTEGER1 = internal2 = external · Integer32
All entries statically configured by the customer (i.e. all entries in the top half of the table) will have the flag set to 'internal'. All IP addresses obtained due to external resolution of the domain name (that is, entries in the bottom half of the table) will have this flag set to 'external'.
mgDomainNameTable
1.3.6.1.4.1.351.150.10.1.6.1
Index: mgDomainNameIndex
This table provides the domain names that are configured by users. The domain names could refer to Call Agents, tftp server for CAS file download, external DNS server or announcement server.
mgDomainNameIndex
1.3.6.1.4.1.351.150.10.1.6.1.1.1
Integer32 (1..65535)
This object serves as index to this table.
mgDomainName
1.3.6.1.4.1.351.150.10.1.6.1.1.2
SnmpAdminStringAn octet string containing administrative information, preferably in human-readable form.
To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8 transformation format described in [RFC2279].
Since additional code points are added by amendments to the 10646 standard from time to time, implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff. Byte sequences that do not correspond to the valid UTF-8 encoding of a code point or are outside this range are prohibited.
The use of control codes should be avoided.
When it is necessary to represent a newline, the control code sequence CR LF should be used.
The use of leading or trailing white space should be avoided.
For code points not directly supported by user interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.
For information encoded in 7-bit US-ASCII, the UTF-8 encoding is identical to the US-ASCII encoding.
UTF-8 may require multiple bytes to represent a single character / code point; thus the length of this object in octets may be different from the number of characters encoded. Similarly, size constraints refer to the number of encoded octets, not the number of characters represented by an encoding.
Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction MUST be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC3416].
Note that the size of an SnmpAdminString object is measured in octets, not characters. SIZE (1..64) · OCTET STRING · hint 255t
This object denotes the domain name of MGCs, tftp server, external DNS server or announcement server. Once the row has become active, this value may not be changed.
This object determines the kind of DNS resolution to be applied for a particular domain name.
'internalOnly' means that the gateway will not try to resolve the IP address for this domain name using external DNS. The IP address/es for this domain name will be obtained from the first half of mgcResolutionTable, which are added by the user.
'externalOnly' means the IP address for this domain name will be resolved externally using external DNS.
'internalFirst' means the first preference will be given to statically provisioned IP address/es, followed the IP address/es resolved using external DNS.
'externalFirst' means the first preference will be given to IP addresses resolved using external DNS followed by statically provisioned IP addresses.
This object can be modified when mgDomainNameRowStatus is active except that if the mgDomainName refers to external DNS server then this object cannot be changed.
The request to change from 'internalOnly' to other types will be rejected if external DNS server is 'NULL'. The external DNS server can be set to 'NULL' through the object vismExtDnsServerDn in CISCO-VISM-MODULE-MIB.
When user change this object to 'internalOnly' then all the externally resolved IP addresses should be implicitly deleted from mgcResolutionTable.
mgDomainNameRowStatus
1.3.6.1.4.1.351.150.10.1.6.1.1.4
RowStatus1 = active2 = notInService3 = notReady4 = createAndGo5 = createAndWait6 = destroyThe RowStatus textual convention is used to manage the creation and deletion of conceptual rows, and is used as the value of the SYNTAX clause for the status column of a conceptual row (as described in Section 7.7.1 of [2].)
The status column has six defined values:
- `active', which indicates that the conceptual row is available for use by the managed device;
- `notInService', which indicates that the conceptual row exists in the agent, but is unavailable for use by the managed device (see NOTE below); 'notInService' has no implication regarding the internal consistency of the row, availability of resources, or consistency with the current state of the managed device;
- `notReady', which indicates that the conceptual row exists in the agent, but is missing information necessary in order to be available for use by the managed device (i.e., one or more required columns in the conceptual row have not been instanciated);
- `createAndGo', which is supplied by a management station wishing to create a new instance of a conceptual row and to have its status automatically set to active, making it available for use by the managed device;
- `createAndWait', which is supplied by a management station wishing to create a new instance of a conceptual row (but not make it available for use by the managed device); and, - `destroy', which is supplied by a management station wishing to delete all of the instances associated with an existing conceptual row.
Whereas five of the six values (all except `notReady') may be specified in a management protocol set operation, only three values will be returned in response to a management
protocol retrieval operation: `notReady', `notInService' or
`active'. That is, when queried, an existing conceptual row
has only three states: it is either available for use by
the managed device (the status column has value `active'); it is not available for use by the managed device, though the agent has sufficient information to attempt to make it so (the status column has value `notInService'); or, it is not available for use by the managed device, and an attempt to make it so would fail because the agent has insufficient information (the state column has value `notReady').
NOTE WELL
This textual convention may be used for a MIB table, irrespective of whether the values of that table's conceptual rows are able to be modified while it is active, or whether its conceptual rows must be taken out of service in order to be modified. That is, it is the responsibility of the DESCRIPTION clause of the status column to specify whether the status column must not be `active' in order for the value of some other column of the same conceptual row to be modified. If such a specification is made, affected columns may be changed by an SNMP set PDU if the RowStatus would not be equal to `active' either immediately before or after processing the PDU. In other words, if the PDU also contained a varbind that would change the RowStatus value, the column in question may be changed if the RowStatus was not equal to `active' as the PDU was received, or if the varbind sets the status to a value other than 'active'.
Also note that whenever any elements of a row exist, the RowStatus column must also exist.
To summarize the effect of having a conceptual row with a status column having a SYNTAX clause value of RowStatus, consider the following state diagram:
STATE +--------------+-----------+-------------+-------------
| A | B | C | D
| |status col.|status column|
|status column | is | is |status column
ACTION |does not exist| notReady | notInService| is active
--------------+--------------+-----------+-------------+-------------
set status |noError ->D|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndGo |inconsistent- | | |
| Value| | |
--------------+--------------+-----------+-------------+-------------
set status |noError see 1|inconsist- |inconsistent-|inconsistent-
column to | or | entValue| Value| Value
createAndWait |wrongValue | | |
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError
column to | Value| entValue| |
active | | | |
| | or | |
| | | |
| |see 2 ->D|see 8 ->D| ->D
--------------+--------------+-----------+-------------+-------------
set status |inconsistent- |inconsist- |noError |noError ->C
column to | Value| entValue| |
notInService | | | |
| | or | | or
| | | |
| |see 3 ->C| ->C|see 6
--------------+--------------+-----------+-------------+-------------
set status |noError |noError |noError |noError ->A
column to | | | | or
destroy | ->A| ->A| ->A|see 7
--------------+--------------+-----------+-------------+-------------
set any other |see 4 |noError |noError |see 5
column to some| | | |
value | | see 1| ->C| ->D
--------------+--------------+-----------+-------------+-------------
(1) goto B or C, depending on information available to the agent.
(2) if other variable bindings included in the same PDU, provide values for all columns which are missing but required, and all columns have acceptable values, then return noError and goto D.
(3) if other variable bindings included in the same PDU, provide legal values for all columns which are missing but required, then return noError and goto C.
(4) at the discretion of the agent, the return value may be either:
inconsistentName: because the agent does not choose to
create such an instance when the corresponding RowStatus instance does not exist, or
inconsistentValue: if the supplied value is
inconsistent with the state of some other MIB object's value, or
noError: because the agent chooses to create the instance.
If noError is returned, then the instance of the status column must also be created, and the new state is B or C, depending on the information available to the agent. If inconsistentName or inconsistentValue is returned, the row remains in state A.
(5) depending on the MIB definition for the column/table, either noError or inconsistentValue may be returned.
(6) the return value can indicate one of the following errors:
wrongValue: because the agent does not support notInService (e.g., an agent which does not support createAndWait), or
inconsistentValue: because the agent is unable to take the row out of service at this time, perhaps because it is in use and cannot be de-activated.
(7) the return value can indicate the following error:
inconsistentValue: because the agent is unable to remove the row at this time, perhaps because it is in use and cannot be de-activated.
(8) the transition to D can fail, e.g., if the values of the conceptual row are inconsistent, then the error code would be inconsistentValue.
NOTE: Other processing of (this and other varbinds of) the set request may result in a response other than noError being returned, e.g., wrongValue, noCreation, etc.
Conceptual Row Creation
There are four potential interactions when creating a
conceptual row: selecting an instance-identifier which is
not in use; creating the conceptual row; initializing any objects for which the agent does not supply a default; and, making the conceptual row available for use by the managed device.
Interaction 1: Selecting an Instance-Identifier
The algorithm used to select an instance-identifier varies for each conceptual row. In some cases, the instance- identifier is semantically significant, e.g., the destination address of a route, and a management station selects the instance-identifier according to the semantics.
In other cases, the instance-identifier is used solely to distinguish conceptual rows, and a management station without specific knowledge of the conceptual row might examine the instances present in order to determine an unused instance-identifier. (This approach may be used, but it is often highly sub-optimal; however, it is also a questionable practice for a naive management station to attempt conceptual row creation.)
Alternately, the MIB module which defines the conceptual row might provide one or more objects which provide assistance in determining an unused instance-identifier. For example, if the conceptual row is indexed by an integer-value, then an object having an integer-valued SYNTAX clause might be defined for such a purpose, allowing a management station to issue a management protocol retrieval operation. In order to avoid unnecessary collisions between competing management stations, `adjacent' retrievals of this object should be different.
Finally, the management station could select a pseudo-random number to use as the index. In the event that this index
was already in use and an inconsistentValue was returned in response to the management protocol set operation, the management station should simply select a new pseudo-random number and retry the operation.
A MIB designer should choose between the two latter algorithms based on the size of the table (and therefore the efficiency of each algorithm). For tables in which a large number of entries are expected, it is recommended that a MIB object be defined that returns an acceptable index for creation. For tables with small numbers of entries, it is recommended that the latter pseudo-random index mechanism be used.
Interaction 2: Creating the Conceptual Row
Once an unused instance-identifier has been selected, the management station determines if it wishes to create and activate the conceptual row in one transaction or in a negotiated set of interactions.
Interaction 2a: Creating and Activating the Conceptual Row
The management station must first determine the column requirements, i.e., it must determine those columns for which it must or must not provide values. Depending on the complexity of the table and the management station's knowledge of the agent's capabilities, this determination can be made locally by the management station. Alternately, the management station issues a management protocol get operation to examine all columns in the conceptual row that it wishes to create. In response, for each column, there are three possible outcomes:
- a value is returned, indicating that some other management station has already created this conceptual row. We return to interaction 1.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it should supply a value for this column when the conceptual row is to be created.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
Once the column requirements have been determined, a management protocol set operation is accordingly issued. This operation also sets the new instance of the status column to `createAndGo'.
When the agent processes the set operation, it verifies that it has sufficient information to make the conceptual row available for use by the managed device. The information
available to the agent is provided by two sources: the
management protocol set operation which creates the conceptual row, and, implementation-specific defaults supplied by the agent (note that an agent must provide implementation-specific defaults for at least those objects which it implements as read-only). If there is sufficient information available, then the conceptual row is created, a `noError' response is returned, the status column is set to `active', and no further interactions are necessary (i.e., interactions 3 and 4 are skipped). If there is insufficient information, then the conceptual row is not created, and the set operation fails with an error of `inconsistentValue'. On this error, the management station can issue a management protocol retrieval operation to determine if this was because it failed to specify a value for a required column, or, because the selected instance of the status column already existed. In the latter case, we return to interaction 1. In the former case, the management station can re-issue the set operation with the additional information, or begin interaction 2 again using `createAndWait' in order to negotiate creation of the conceptual row.
NOTE WELL
Regardless of the method used to determine the column requirements, it is possible that the management station might deem a column necessary when, in fact, the agent will not allow that particular columnar instance to be created or written. In this case, the management protocol set operation will fail with an error such as `noCreation' or `notWritable'. In this case, the management station decides whether it needs to be able to set a value for that particular columnar instance. If not, the management station re-issues the management protocol set operation, but without setting a value for that particular columnar instance; otherwise, the management station aborts the row creation algorithm.
Interaction 2b: Negotiating the Creation of the Conceptual Row
The management station issues a management protocol set operation which sets the desired instance of the status column to `createAndWait'. If the agent is unwilling to process a request of this sort, the set operation fails with an error of `wrongValue'. (As a consequence, such an agent must be prepared to accept a single management protocol set operation, i.e., interaction 2a above, containing all of the
columns indicated by its column requirements.) Otherwise,
the conceptual row is created, a `noError' response is returned, and the status column is immediately set to either `notInService' or `notReady', depending on whether it has sufficient information to (attempt to) make the conceptual row available for use by the managed device. If there is sufficient information available, then the status column is set to `notInService'; otherwise, if there is insufficient information, then the status column is set to `notReady'. Regardless, we proceed to interaction 3.
Interaction 3: Initializing non-defaulted Objects
The management station must now determine the column requirements. It issues a management protocol get operation to examine all columns in the created conceptual row. In the response, for each column, there are three possible outcomes:
- a value is returned, indicating that the agent implements the object-type associated with this column and had sufficient information to provide a value. For those columns to which the agent provides read-create access (and for which the agent allows their values to be changed after their creation), a value return tells the management station that it may issue additional management protocol set operations, if it desires, in order to change the value associated with this column.
- the exception `noSuchInstance' is returned, indicating that the agent implements the object-type associated with this column, and that this column in at least one conceptual row would be accessible in the MIB view used by the retrieval were it to exist. However, the agent does not have sufficient information to provide a value, and until a value is provided, the conceptual row may not be made available for use by the managed device. For those columns to which the agent provides read-create access, the `noSuchInstance' exception tells the management station that it must issue additional management protocol set operations, in order to provide a value associated with this column.
- the exception `noSuchObject' is returned, indicating that the agent does not implement the object-type associated with this column or that there is no conceptual row for which this column would be accessible in the MIB view used by the retrieval. As such, the management station can not issue any management protocol set operations to create an instance of this column.
If the value associated with the status column is `notReady', then the management station must first deal with all `noSuchInstance' columns, if any. Having done so, the value of the status column becomes `notInService', and we proceed to interaction 4.
Interaction 4: Making the Conceptual Row Available
Once the management station is satisfied with the values associated with the columns of the conceptual row, it issues a management protocol set operation to set the status column to `active'. If the agent has sufficient information to make the conceptual row available for use by the managed device, the management protocol set operation succeeds (a `noError' response is returned). Otherwise, the management protocol set operation fails with an error of `inconsistentValue'.
NOTE WELL
A conceptual row having a status column with value `notInService' or `notReady' is unavailable to the managed device. As such, it is possible for the managed device to create its own instances during the time between the management protocol set operation which sets the status column to `createAndWait' and the management protocol set operation which sets the status column to `active'. In this case, when the management protocol set operation is issued to set the status column to `active', the values held in the agent supersede those used by the managed device.
If the management station is prevented from setting the status column to `active' (e.g., due to management station or network failure) the conceptual row will be left in the `notInService' or `notReady' state, consuming resources indefinitely. The agent must detect conceptual rows that have been in either state for an abnormally long period of time and remove them. It is the responsibility of the DESCRIPTION clause of the status column to indicate what an abnormally long period of time would be. This period of time should be long enough to allow for human response time (including `think time') between the creation of the conceptual row and the setting of the status to `active'. In the absence of such information in the DESCRIPTION clause, it is suggested that this period be approximately 5 minutes in length. This removal action applies not only to newly-created rows, but also to previously active rows which are set to, and left in, the notInService state for a prolonged period exceeding that which is considered normal for such a conceptual row.
Conceptual Row Suspension
When a conceptual row is `active', the management station may issue a management protocol set operation which sets the instance of the status column to `notInService'. If the agent is unwilling to do so, the set operation fails with an error of `wrongValue' or `inconsistentValue'. Otherwise, the conceptual row is taken out of service, and a `noError' response is returned. It is the responsibility of the DESCRIPTION clause of the status column to indicate under what circumstances the status column should be taken out of service (e.g., in order for the value of some other column of the same conceptual row to be modified).
Conceptual Row Deletion
For deletion of conceptual rows, a management protocol set operation is issued which sets the instance of the status column to `destroy'. This request may be made regardless of the current value of the status column (e.g., it is possible to delete conceptual rows which are either `notReady',
`notInService' or `active'.) If the operation succeeds,
then all instances associated with the conceptual row are immediately removed. · Integer32
Controls the creation and deletion and of a table entry.
An entry may be created using the 'createAndGo' option. User can only set mgDnsResolutionType to 'internalOnly'.
The request to set an entry with mgDnsResolutionType of 'externalOnly', 'internalFirst' or 'externalFirst' would be rejected if the external DNS server is 'NULL'.
When the row is successfully created, the RowStatus would be set to 'active' by the agent.
An entry may be deleted by setting the RowStatus to 'destroy'. The deletion of an entry will be rejected if there is still reference to this domain name. For example, it cannot be deleted if it is configured as MGC, tftp server, external DNS server or announcement server. Also user added IPs should already been deleted. After delete the domain name externally resolved IPs are purged implicitly.
The request to change from 'internalOnly' to other types will be rejected if external DNS server is 'NULL'.
Other options such as `createAndWait', 'notInService', 'notReady' will not be used.