SNMP Reference Guide
Table Of Contents
- Introduction
- Audience
- What’s New in this Release
- Introduction to the SNMP Reference Guide
- General Content
- Server Administrator Instrumentation MIB
- Server Administrator Remote Access MIB
- Server Administrator Baseboard Management Controller, ASF MIB
- Server Administrator Field Replaceable Unit MIB
- Server Administrator Storage Management MIB
- Server Administrator Change Management MIB
- Dell RAC Out-of-Band MIB
- How This Guide Defines Technical Terms
- SNMP Basic Terminology
- Frequently Used Terms in Variable Names
- Tables
- Reference Guide Content Tables
- Section Organization
- Other Documents You May Need
- Introduction to the Server Administrator SNMP Subagent
- Instrumentation MIB Version Group
- Systems Management Software Group
- Systems Management Software
- Systems Management Software Name
- Systems Management Software Version Number Name
- Systems Management Software Build Number
- Systems Management Software Description Name
- Systems Management Software Supported Protocol
- Systems Management Software Preferred Protocol
- Systems Management Software Update Level Name
- Systems Management Software URL Name
- Systems Management Software Language Name
- Systems Management Software Global Version Name
- Systems Management Software Feature Flags
- Systems Management Software SNMP Agent Feature Flags
- Systems Management Software Manufacturer Name
- Systems Management Software Variable Values
- Systems Management Software
- System State Group
- Chassis Information Group
- Operating System Group
- System Resource Group
- Power Group
- Thermal Group
- User Security Group
- Remote Flash BIOS Group
- Port Group
- Device Group
- Slot Group
- Memory Group
- BIOS Setup Control Group
- Local Response Agent Group
- Cost of Ownership Group
- Remote Access Group
- Cluster Group
- Baseboard Management Controller Group
- Field Replaceable Unit Group
- Storage Management Group
- Storage Management Group
- Storage Management Information Group
- Global Data Group
- Physical Devices Group
- Controller Table
- Channel Table
- Enclosure Table
- Array Disk Table
- Array Disk Enclosure Connection Table
- Array Disk Channel Connection Table
- Fan Table
- Fan Connection Table
- Power Supply Table
- Power Supply Connection Table
- Temperature Probe Table
- Temperature Probe Connection Table
- Enclosure Management Module Table
- Enclosure Management Module Connection Table
- Battery Table
- Battery Connection Table
- Logical Devices Group
- Storage Management Event Group
- Change Management Group
- Dell RAC Out-of-Band Group
- Product Information
- Chassis Status
- DRsGlobalSystemStatus
- DRsGlobalCurrStatus
- DRsIOMCurrStatus
- DRsKVMCurrStatus
- DRsRedCurrStatus
- DRsPowerCurrStatus
- DRsFanCurrStatus
- DRsBladeCurrStatus
- DRsTempCurrStatus
- DRsCMCCurrStatus
- DRsGlobalPrevStatus
- DRsIOMPrevStatus
- DRsKVMPrevStatus
- DRsRedPrevStatus
- DRsPowerPrevStatus
- DRsFanPrevStatus
- DRsBladePrevStatus
- DRsTempPrevStatus
- DRsCMCPrevStatus
- DRsIOMChangeTime
- DRsKVMChangeTime
- DRsRedChangeTime
- DRsPowerChangeTime
- DRsFanChangeTime
- DRsBladeChangeTime
- DRsTempChangeTime
- DRsCMCChangeTime
- Chassis Power
- CMC Power Information
- CMC PSU Information
- Chassis Alerts
- Legacy Alerting
- Traps
- Trap Variables
- Understanding the Trap Description
- Understanding Trap Severity
- Instrumentation Traps
- Miscellaneous Traps
- Temperature Probe Traps
- Cooling Device Traps
- Voltage Probe Traps
- Amperage Probe Traps
- Chassis Intrusion Traps
- Redundancy Unit Traps
- Power Supply Traps
- Memory Device Traps
- Fan Enclosure Traps
- AC Power Cord Traps
- Hardware Log Traps
- Processor Device Status Traps
- Pluggable Device Traps
- Battery Traps
- RAC Traps
- BMC Traps
- Storage Management Alert Reference
- Standard Data Type Definitions
- SNMP Sample Output
- Glossary
- Index
40 Introduction
Management Actions
Management actions can be performed using the SNMP Set command.
These actions can consist of configuring a phone number for the system’s
owner, rebooting a system, or changing the asset tag of the system. See the
previous section, "SNMP Security," for limitations on Set operations.
SNMP Traps
SNMP is frequently used to monitor systems for fault conditions such as
temperature violations, hard drive failures, and so on. Management
applications can monitor for these conditions by polling the appropriate
OIDs with the Get command and analyzing the returned data. This method
has its drawbacks. If it is done frequently, significant amounts of network
bandwidth can be consumed. If it is done infrequently, the response to the
fault condition may not occur in a timely fashion. SNMP traps avoid these
limitations of the polling method.
An SNMP trap is an asynchronous event indicating that something
significant has occurred. This is analogous to a pager receiving an important
message, except that the SNMP trap frequently contains all the information
needed to diagnose a fault.
Two drawbacks to SNMP traps are that they are sent using UDP, which is not
a guaranteed delivery mechanism, and that they are not acknowledged by
the receiver.
An SNMP trap message contains the trap’s enterprise OID, the agent
IP address, a generic trap ID, the specific trap ID, a time stamp, and zero or
more variable bindings (varbinds). The combination of an enterprise OID
and a specific trap ID uniquely identifies each Server Administrator-defined
trap. A varbind consists of an OID and its value and provides additional
information about the trap.
In order for a management system to receive SNMP traps from a managed
system, the node must be configured to send traps to the management
system. Trap destination configuration is dependent on the operating system.
When this configuration is done, a management application on the
management system can wait for traps and act on them when received.
For a list of traps supported by the server administrator SNMP subagent,
see "Traps."