SNMP Configuration and Management Manual

TCP/IP Subagent
SNMP Configuration and Management Manual—424777-006
8-8
Unavailable Resources
simply encodes and sends an SPI request to the subsystem. When the response is
received, the TCP/IP Subagent extracts the desired token, field, or word offset from the
reply buffer and returns the obtained value.
Certain requests require more complex SPI interaction. When an intermediate value
must be obtained, the value returned is obtained after two or more successive SPI
interactions.
A few MIB-II objects have constant values declared. Some objects (mostly counters)
are implemented by the TCP/IP Subagent itself.
For MIB values from the SLSA subsystem, ZLANMSRL calls are made, the content
buffer returned is processed, and fields are extracted from it.
Specific information about how the TCP/IP Subagent maintains MIB values is provided
in later subsections that describe each group in detail.
Unavailable Resources
If the TCP/IP subsystem being managed by the TCP/IP Subagent becomes
unavailable (for instance, if the SCP process or the subsystem management or I/O
process becomes unavailable), the entire MIB-II table is cleared, and an SNMP
noSuchName error is returned to the SNMP manager in the response to the request.
The value of the TCP/IP Subagent’s private ztsaKeepAliveTimer object defines the
interval at which the TCP/IP Subagent looks for lost resources. If the SCP process
goes away, for example, and ztsaKeepAliveTimer is set to 30, the TCP/IP Subagent
attempts to connect to the SCP process every 30 seconds. Refer to Starting the
TCP/IP Subagent on page 8-12 for complete information on the ztsaKeepAliveTimer
object.
Reporting Values for Uninstrumented Objects
When it receives a request against objects for which there is no HP instrumentation,
the TCP/IP Subagent returns the following values:
•
A zero (0) for Get and GetNext requests against unsupported MIB objects defined
as integers, counters, or gauges
•
A null value for Get and GetNext requests against unsupported MIB objects
defined as strings
Unsupported objects are identified in the RFC compliance tables following each
supported MIB-II group’s object definition table.
Note. When the managed TCP/IP resources are unavailable, you can still access private
TCP/IP Subagent MIB objects to obtain information about and control various aspects of the
TCP/IP Subagent.