Reference: RFC 2030 - Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI; Section 5.
The highest SNTP version this client supports. Per RFC 2030, higher versions are required to be backwards compatible with all lower versions with the exception of version 0.
agentSntpClientSupportedMode
1.3.6.1.4.1.4526.10.17.1.1.2
SntpClientAdminModeAn SNTP client may operate in any of several modes. At least one mode other than disabled must be supported by a client.
disabled - SNTP is not administrative. No SNTP requests are sent from the client nor are any received SNTP messages processed.
unicast - SNTP operates in a point-to-point fashion. A unicast client sends a request to a designated server at its unicast address and expects a reply from which it can determine the time and, optionally, the round-trip delay and local clock offset relative to the server.
broadcast - SNTP operates using the local broadcast address. The broadcast address has a single subnet scope. The SNTP server uses a broadcast address to send unsolicited SNTP messages to clients. The client listens on this address and sends no requests for updates. The broadcast address is determined by the address and netmask of the service port over which the SNTP client is operating.
multicast - SNTP operates in a point-to-multipoint fashion. A multicast client listens on the dedicated broadcast address or multicast group address.Reference: RFC 2030 - Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI; Section 2. · BITS
The SNTP client administrative modes that this device supports. A client may support more than one administrative mode.
The current administrative mode of the SNTP client. A SET of this object will cause the SNTP client to change administrative modes. A SET request MUST have only 1 bit set since is not possible to operate in multiple modes simultaneously. SETs of this object are limited to values supported by the device as specified by agentSntpClientSupportedMode.
agentSntpClientPort
1.3.6.1.4.1.4526.10.17.1.1.4
InetPortNumberRepresents a 16 bit port number of an Internet transport layer protocol. Port numbers are assigned by IANA. A current list of all assignments is available from <http://www.iana.org/>.
The value zero is object-specific and must be defined as part of the description of any object that uses this syntax. Examples of the usage of zero might include situations where a port number is unknown, or when the value zero is used as a wildcard in a filter.Reference: STD 6 (RFC 768), STD 7 (RFC 793) and RFC 2960 (1..65535) · Unsigned32 · hint d
The local port number used to listen for broadcasts and responses from servers.
agentSntpClientLastUpdateTime
1.3.6.1.4.1.4526.10.17.1.1.5
DateAndTimeA date-time specification.
field octets contents range
----- ------ -------- -----
1 1-2 year* 0..65536
2 3 month 1..12
3 4 day 1..31
4 5 hour 0..23
5 6 minutes 0..59
6 7 seconds 0..60
(use 60 for leap-second)
7 8 deci-seconds 0..9
8 9 direction from UTC '+' / '-'
9 10 hours from UTC* 0..13
10 11 minutes from UTC 0..59
* Notes: - the value of year is in network-byte order - daylight saving time in New Zealand is +13
For example, Tuesday May 26, 1992 at 1:30:15 PM EDT would be displayed as:
1992-5-26,13:30:15.0,-4:0
Note that if only local time is known, then timezone information (fields 8-10) is not present. SIZE (8 | 11) · OCTET STRING · hint 2d-1d-1d,1d:1d:1d.1d,1a1d:1d
The local date and time that the SNTP client last updated the system time on the device since agent reboot. This time is updated for all non-disabled administrative modes of the SNTP client. If the SNTP client has not updated the time then the client MUST return '00000000'H.
agentSntpClientLastAttemptTime
1.3.6.1.4.1.4526.10.17.1.1.6
DateAndTimeA date-time specification.
field octets contents range
----- ------ -------- -----
1 1-2 year* 0..65536
2 3 month 1..12
3 4 day 1..31
4 5 hour 0..23
5 6 minutes 0..59
6 7 seconds 0..60
(use 60 for leap-second)
7 8 deci-seconds 0..9
8 9 direction from UTC '+' / '-'
9 10 hours from UTC* 0..13
10 11 minutes from UTC 0..59
* Notes: - the value of year is in network-byte order - daylight saving time in New Zealand is +13
For example, Tuesday May 26, 1992 at 1:30:15 PM EDT would be displayed as:
1992-5-26,13:30:15.0,-4:0
Note that if only local time is known, then timezone information (fields 8-10) is not present. SIZE (8 | 11) · OCTET STRING · hint 2d-1d-1d,1d:1d:1d.1d,1a1d:1d
The local date and time of the last SNTP request or unsolicited SNTP message for this SNTP client since agent reboot. This value is a timestamp for the agentSntpClientLastAttemptStatus object. When the agentSntpClientLastAttemptStatus has a value of success(2), this object's value should be equal to the value returned by agentSntpClientLastUpdateTime. If no SNTP frames have been processed by the SNTP client then the client MUST return '00000000'H. This object is updated for all non-disabled administrative modes of the SNTP client.
agentSntpClientLastAttemptStatus
1.3.6.1.4.1.4526.10.17.1.1.7
SntpClientUpdateStatus1 = other2 = success3 = requestTimedOut4 = badDateEncoded5 = versionNotSupported6 = serverUnsychronized7 = serverKissOfDeathThe status of the last received response or broadcast from a configured server. These values are appropriate for all administrative modes.
other - None of the following enumeration values.
success - The SNTP operation was successful and the system time was updated.
requestTimedOut - An SNTP poll request timed out without receiving a response from the SNTP server.
badDateEncoded - The time provided by the SNTP server was not valid.
versionNotSupported - The SNTP version supported by the server is not compatible with the version supported by the client. This is indicated by the server returning a version later than the version configured for that server or a version of '0'.
serverUnsychronized - The SNTP server is not synchronized with its peers. This is indicated via the 'leap indicator' field on the SNTP message.
serverKissOfDeath - The SNTP server indicated that no further polls are to be sent to this server. This is indicated by a stratum field field equal to 0 in a message received from a server.Reference: RFC 2030 - Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI; Section 4. · Integer32
The status of the last SNTP request or unsolicited SNTP message for this SNTP client since agent reboot. The status is updated for all non-disabled administrative modes of the SNTP client.
agentSntpClientServerAddressType
1.3.6.1.4.1.4526.10.17.1.1.8
InetAddressType0 = unknown1 = ipv42 = ipv63 = ipv4z4 = ipv6z16 = dnsA value that represents a type of Internet address.
unknown(0) An unknown address type. This value MUST
be used if the value of the corresponding InetAddress object is a zero-length string. It may also be used to indicate an IP address that is not in one of the formats defined below.
ipv4(1) An IPv4 address as defined by the
InetAddressIPv4 textual convention.
ipv6(2) An IPv6 address as defined by the
InetAddressIPv6 textual convention.
ipv4z(3) A non-global IPv4 address including a zone
index as defined by the InetAddressIPv4z textual convention.
ipv6z(4) A non-global IPv6 address including a zone
index as defined by the InetAddressIPv6z textual convention.
dns(16) A DNS domain name as defined by the
InetAddressDNS textual convention.
Each definition of a concrete InetAddressType value must be accompanied by a definition of a textual convention for use with that InetAddressType.
To support future extensions, the InetAddressType textual convention SHOULD NOT be sub-typed in object type definitions. It MAY be sub-typed in compliance statements in order to require only a subset of these address types for a compliant implementation.
Implementations must ensure that InetAddressType objects and any dependent objects (e.g., InetAddress objects) are consistent. An inconsistentValue error must be generated if an attempt to change an InetAddressType object would, for example, lead to an undefined InetAddress value. In particular, InetAddressType/InetAddress pairs must be changed together if the address type changes (e.g., from ipv6(2) to ipv4(1)). · Integer32
The address type of the SNTP server as identified by the last received packet. Support for all address types is NOT REQUIRED.
agentSntpClientServerAddress
1.3.6.1.4.1.4526.10.17.1.1.9
InetAddressDenotes a generic Internet address.
An InetAddress value is always interpreted within the context of an InetAddressType value. Every usage of the InetAddress textual convention is required to specify the InetAddressType object that provides the context. It is suggested that the InetAddressType object be logically registered before the object(s) that use the InetAddress textual convention, if they appear in the same logical row.
The value of an InetAddress object must always be consistent with the value of the associated InetAddressType object. Attempts to set an InetAddress object to a value inconsistent with the associated InetAddressType must fail with an inconsistentValue error.
When this textual convention is used as the syntax of an index object, there may be issues with the limit of 128 sub-identifiers specified in SMIv2, STD 58. In this case, the object definition MUST include a 'SIZE' clause to limit the number of potential instance sub-identifiers; otherwise the applicable constraints MUST be stated in the appropriate conceptual row DESCRIPTION clauses, or in the surrounding documentation if there is no single DESCRIPTION clause that is appropriate. SIZE (1..64) · OCTET STRING
The encoded address of the SNTP server as identified by the last received packet.
agentSntpClientServerMode
1.3.6.1.4.1.4526.10.17.1.1.10
Unsigned32 (0..7)
This is a 3-bit integer identifying the mode of the server as indicated in the last received packet with values defined as follows:
Mode Meaning ------------------------------------ 0 reserved 1 symmetric active 2 symmetric passive 3 client 4 server 5 broadcast 6 reserved for NTP control message 7 reserved for private use
agentSntpClientServerStratum
1.3.6.1.4.1.4526.10.17.1.1.11
Unsigned32 (0..255)
This is an 8-bit integer identifying the stratum of the server as indicated in the last received packet with values defined as follows:
Stratum Meaning ------------------------------------
0 unspecified
1 primary reference
2-15 secondary reference
16-255 reserved
agentSntpClientServerRefClkId
1.3.6.1.4.1.4526.10.17.1.1.12
OCTET STRING SIZE (4)
This is the value of the Reference Identifier in the last received packet defined as follows. Reference Identifier: This is a 32-bit bitstring identifying the particular reference source. In the case of NTP Version 3 or Version 4 stratum-0 (unspecified) or stratum-1 (primary) servers, this is a four-character ASCII string, left justified and zero padded to 32 bits. In NTP Version 3 secondary servers, this is the 32-bit IPv4 address of the reference source. In NTP Version 4 secondary servers, this is the low order 32 bits of the latest transmit timestamp of the reference source.
agentSntpClientPollInterval
1.3.6.1.4.1.4526.10.17.1.1.13
Unsigned32 (6..10) · seconds
The minimum number of seconds between successive SNTP polls of the server in seconds as a power of two. This polling interval is used for SNTP requests in unicast(1) or broadcast(2) administrative mode.
agentSntpClientUnicastPollInterval
1.3.6.1.4.1.4526.10.17.1.2.1
Unsigned32 (6..10) · seconds
The minimum number of seconds between successive SNTP polls of the server in seconds as a power of two. This polling interval is used for SNTP requests in unicast(1) administrative mode.
agentSntpClientUnicastPollTimeout
1.3.6.1.4.1.4526.10.17.1.2.2
Unsigned32 (1..30) · seconds
The number of seconds to wait for a response from a SNTP server before considering the attempt to have 'timed out'. This timeout is used for SNTP requests in unicast(1) administrative mode.
agentSntpClientUnicastPollRetry
1.3.6.1.4.1.4526.10.17.1.2.3
Unsigned32 (0..10)
The number of times to retry a request to the same SNTP server that has 'timed out.'. This retry count is used for directed SNTP requests in unicast(1) administrative mode. For example, assume this object has been SET to a value of 2. When the SNTP client queries a given server it will send 1 SNTP request frame. If that original attempt fails, the client will retry up to a maximum of 2 more times before declaring the unicast poll unsuccessful and attempting the next server.
agentSntpClientUcastServerMaxEntries
1.3.6.1.4.1.4526.10.17.1.2.4
Unsigned32 (1..3)
The maximum number of server entries that are allowed in the agentSntpClientUcastServerTable.
agentSntpClientUcastServerCurrEntries
1.3.6.1.4.1.4526.10.17.1.2.5
Gauge32 (0..3)
The current number of server entries in the agentSntpClientUcastServerTable.
agentSntpClientBroadcastCount
1.3.6.1.4.1.4526.10.17.1.3.1
Counter32
The number of unsolicited broadcast SNTP messages that have been received and processed by the SNTP client. Unsolicited SNTP broadcast frames will not be counted unless the SNTP agent is operating in broadcast(3) mode, as specified by agentSntpClientMode.
agentSntpClientBroadcastInterval
1.3.6.1.4.1.4526.10.17.1.3.2
Unsigned32 (6..10) · seconds
The number of seconds the client will wait before processing another broadcast packet expressed as a power of two. Packets received during the wait interval are silently discarded.
Table details
agentSntpClientUcastServerTable
1.3.6.1.4.1.4526.10.17.1.2.6
Index: agentSntpClientUcastServerIndex
A table containing configuration and statistical information for unicast SNTP servers. Each server entry is represented by single conceptual row in this table.
agentSntpClientUcastServerIndex
1.3.6.1.4.1.4526.10.17.1.2.6.1.1
Unsigned32
This object uniquely identifies the entry in the table.
agentSntpClientUcastServerAddressType
1.3.6.1.4.1.4526.10.17.1.2.6.1.2
InetAddressType0 = unknown1 = ipv42 = ipv63 = ipv4z4 = ipv6z16 = dnsA value that represents a type of Internet address.
unknown(0) An unknown address type. This value MUST
be used if the value of the corresponding InetAddress object is a zero-length string. It may also be used to indicate an IP address that is not in one of the formats defined below.
ipv4(1) An IPv4 address as defined by the
InetAddressIPv4 textual convention.
ipv6(2) An IPv6 address as defined by the
InetAddressIPv6 textual convention.
ipv4z(3) A non-global IPv4 address including a zone
index as defined by the InetAddressIPv4z textual convention.
ipv6z(4) A non-global IPv6 address including a zone
index as defined by the InetAddressIPv6z textual convention.
dns(16) A DNS domain name as defined by the
InetAddressDNS textual convention.
Each definition of a concrete InetAddressType value must be accompanied by a definition of a textual convention for use with that InetAddressType.
To support future extensions, the InetAddressType textual convention SHOULD NOT be sub-typed in object type definitions. It MAY be sub-typed in compliance statements in order to require only a subset of these address types for a compliant implementation.
Implementations must ensure that InetAddressType objects and any dependent objects (e.g., InetAddress objects) are consistent. An inconsistentValue error must be generated if an attempt to change an InetAddressType object would, for example, lead to an undefined InetAddress value. In particular, InetAddressType/InetAddress pairs must be changed together if the address type changes (e.g., from ipv6(2) to ipv4(1)). · Integer32
This object specifies how agentSntpClientUcastServerAddr is encoded. Support for all possible enumerations defined by InetAddressType is NOT REQUIRED.
agentSntpClientUcastServerAddress
1.3.6.1.4.1.4526.10.17.1.2.6.1.3
InetAddressDenotes a generic Internet address.
An InetAddress value is always interpreted within the context of an InetAddressType value. Every usage of the InetAddress textual convention is required to specify the InetAddressType object that provides the context. It is suggested that the InetAddressType object be logically registered before the object(s) that use the InetAddress textual convention, if they appear in the same logical row.
The value of an InetAddress object must always be consistent with the value of the associated InetAddressType object. Attempts to set an InetAddress object to a value inconsistent with the associated InetAddressType must fail with an inconsistentValue error.
When this textual convention is used as the syntax of an index object, there may be issues with the limit of 128 sub-identifiers specified in SMIv2, STD 58. In this case, the object definition MUST include a 'SIZE' clause to limit the number of potential instance sub-identifiers; otherwise the applicable constraints MUST be stated in the appropriate conceptual row DESCRIPTION clauses, or in the surrounding documentation if there is no single DESCRIPTION clause that is appropriate. SIZE (1..64) · OCTET STRING
The encoded internet address of an SNTP server. Unicast SNTP requests will be sent to this address. If this address is a DNS hostname, then that hostname SHOULD be resolved into an IP address each time a SNTP request is sent to it.
agentSntpClientUcastServerPort
1.3.6.1.4.1.4526.10.17.1.2.6.1.4
InetPortNumberRepresents a 16 bit port number of an Internet transport layer protocol. Port numbers are assigned by IANA. A current list of all assignments is available from <http://www.iana.org/>.
The value zero is object-specific and must be defined as part of the description of any object that uses this syntax. Examples of the usage of zero might include situations where a port number is unknown, or when the value zero is used as a wildcard in a filter.Reference: STD 6 (RFC 768), STD 7 (RFC 793) and RFC 2960 (1..65535) · Unsigned32 · hint d
The port number on the server to which poll requests are sent. A set request MUST NOT use a value of 0 for this object.
Reference: RFC 2030 - Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI; Section 5.
The SNTP version this server supports. This is the value that will be encoded in NTP polls when operating in unicast(1) administrative mode.
agentSntpClientUcastServerPrecedence
1.3.6.1.4.1.4526.10.17.1.2.6.1.6
Unsigned32 (1..8)
The precedence that this server has in relation to its peers in the determining the sequence of servers to which SNTP requests will be sent. The client continues sending requests to different servers until a successful response is received or all servers are exhausted. This object indicates the order in which to query the servers. A server entry with a precedence of 1 will be queried before a server with a precedence of 2, and so forth. If more than one server has the same precedence then the request order will follow the lexicographical ordering of the entries in this table.
agentSntpClientUcastServerLastUpdateTime
1.3.6.1.4.1.4526.10.17.1.2.6.1.7
DateAndTimeA date-time specification.
field octets contents range
----- ------ -------- -----
1 1-2 year* 0..65536
2 3 month 1..12
3 4 day 1..31
4 5 hour 0..23
5 6 minutes 0..59
6 7 seconds 0..60
(use 60 for leap-second)
7 8 deci-seconds 0..9
8 9 direction from UTC '+' / '-'
9 10 hours from UTC* 0..13
10 11 minutes from UTC 0..59
* Notes: - the value of year is in network-byte order - daylight saving time in New Zealand is +13
For example, Tuesday May 26, 1992 at 1:30:15 PM EDT would be displayed as:
1992-5-26,13:30:15.0,-4:0
Note that if only local time is known, then timezone information (fields 8-10) is not present. SIZE (8 | 11) · OCTET STRING · hint 2d-1d-1d,1d:1d:1d.1d,1a1d:1d
The local date and time that the response from this server was used to update the system time on the device since agent reboot. If the SNTP client has not updated the time using a response from this server then this object MUST return '00000000'H.
agentSntpClientUcastServerLastAttemptTime
1.3.6.1.4.1.4526.10.17.1.2.6.1.8
DateAndTimeA date-time specification.
field octets contents range
----- ------ -------- -----
1 1-2 year* 0..65536
2 3 month 1..12
3 4 day 1..31
4 5 hour 0..23
5 6 minutes 0..59
6 7 seconds 0..60
(use 60 for leap-second)
7 8 deci-seconds 0..9
8 9 direction from UTC '+' / '-'
9 10 hours from UTC* 0..13
10 11 minutes from UTC 0..59
* Notes: - the value of year is in network-byte order - daylight saving time in New Zealand is +13
For example, Tuesday May 26, 1992 at 1:30:15 PM EDT would be displayed as:
1992-5-26,13:30:15.0,-4:0
Note that if only local time is known, then timezone information (fields 8-10) is not present. SIZE (8 | 11) · OCTET STRING · hint 2d-1d-1d,1d:1d:1d.1d,1a1d:1d
The local date and time that this SNTP server was last queried since agent reboot. Essentially, this value is a timestamp for the agentSntpClientUcastServerLastAttemptStatus object. If this server has not been queried then this object MUST return '00000000'H.
agentSntpClientUcastServerLastAttemptStatus
1.3.6.1.4.1.4526.10.17.1.2.6.1.9
SntpClientUpdateStatus1 = other2 = success3 = requestTimedOut4 = badDateEncoded5 = versionNotSupported6 = serverUnsychronized7 = serverKissOfDeathThe status of the last received response or broadcast from a configured server. These values are appropriate for all administrative modes.
other - None of the following enumeration values.
success - The SNTP operation was successful and the system time was updated.
requestTimedOut - An SNTP poll request timed out without receiving a response from the SNTP server.
badDateEncoded - The time provided by the SNTP server was not valid.
versionNotSupported - The SNTP version supported by the server is not compatible with the version supported by the client. This is indicated by the server returning a version later than the version configured for that server or a version of '0'.
serverUnsychronized - The SNTP server is not synchronized with its peers. This is indicated via the 'leap indicator' field on the SNTP message.
serverKissOfDeath - The SNTP server indicated that no further polls are to be sent to this server. This is indicated by a stratum field field equal to 0 in a message received from a server.Reference: RFC 2030 - Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI; Section 4. · Integer32
The status of the last SNTP request to this server since agent reboot. If no requests have been made then this object should return 'other'.
agentSntpClientUcastServerNumRequests
1.3.6.1.4.1.4526.10.17.1.2.6.1.10
Counter32
The number of SNTP requests made to this server since the last agent reboot. This includes retry attempts to the server.
agentSntpClientUcastServerNumFailedRequests
1.3.6.1.4.1.4526.10.17.1.2.6.1.11
Counter32
The number of SNTP requests made to this server that did not result in a successful response since the last agent reboot. This includes retry attempts to the server.
agentSntpClientUcastServerRowStatus
1.3.6.1.4.1.4526.10.17.1.2.6.1.12
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
The row status of this conceptual row in the table.
active - The server is available for use in SNTP client operations. Other writable leaves in this table MAY be modified while the row is in the active state.
notInService - The entry is fully configured but is not available for use in SNTP client operations. The agent MAY transition a row from the active to notInService upon receipt of a kiss of death packet from the server.
createAndGo - This is the preferred mechanism for creating conceptual rows in this table. This value can never be read as the row will always transition immediately to either active or notInService.
destroy - This will remove the conceptual row from the table and make it unavailable for SNTP client operations.