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Overview of SNMP Traps

The SNMP agent provides network management systems with SNMP trap notifications in case of component failure or when critical resources are out of configurable limits. This information is captured in a Management Information Base (MIB).

The SNMP agent can be run on each SRC host. It can monitor any SRC process running on the host and is preconfigured to monitor SRC processes. Additionally, it provides detailed monitoring and configuration of SRC server components.

The SNMP agent automatically discovers SRC components that expose component-specific management information and components that are directory eventing system (DES) clients (that is, have a directory connection managed by DES). When the SNMP agent discovers a component, it adds variables and table entries to its MIB to export the component's management capabilities.

For components that are automatically discovered, the SNMP agent communicates directly with a management server built into the components. For these components, the agent can perform exhaustive tests to determine operability rather than just determining process status. The SNMP agent ensures that the management infrastructure built into the component continues to respond to management requests.

In addition to monitoring components that it automatically discovers, you can also configure the SNMP agent to monitor any process or collection of processes running on its host. The SNMP agent monitors processes by looking at entries in the process table. For many processes that are run only once, such as directory servers, it is sufficient to monitor the single entry in the process table that includes the command used to start the process.

When a component is written in Java or Python, you need to differentiate between the different instances of the Java or Python process because there will be multiple processes in which the executed command is java or python. The technical name field in the component definition allows you to make this differentiation. The technical name of a component is the command that is used to start the process for the component. In the case of a Java program, the technical name is the name of the main Java class that is specified as an argument to the java command. For a Python program, it is the name of the script that is specified as an argument to the python command.

MIBs

The SNMP agent monitors MIB variables. Most variables measure the performance of the system. Some variables are counters, such as the saeLogins variable, which counts the total number of subscriber logins since startup. Some variables are gauges, and their numbers go up and down, such as the saeHeapUsed variable, which measures the Java Virtual Machine heap that is currently in use.

A MIB defines a trap type that is associated with many MIB variables. For traps based on counters, the SNMP agent periodically polls each specified variable. It takes the difference between the previous and current values of the variable and compares that difference with the threshold. If the value has moved up across thresholds, the SNMP agent sends a trap raising an alarm (minor, major, or critical) for the highest threshold crossed to all configured receivers. If the value has moved down across thresholds, the agent sends a trap clearing the alarm of the lowest threshold crossed.

You can configure the polling interval between samples. If you change the polling interval, also adjust the thresholds. For instance, if the critical threshold for SAE logins is 1,000 and the interval is 60 seconds, then a critical alarm is raised if there are more than 1,000 logins in 60 seconds. But if you change the interval to 600 seconds, then you would need to change the threshold to 10,000 to have the same meaning.

For traps based on gauges, the previous value is not needed; the current value is compared with the thresholds.

In the trap tables, there is a field named R/AV, where R means rate, and AV means absolute value. Rate is used for variables that are counters, and it measures the rate of change of the counter. Absolute value is used for variables that are gauges.

For a list of all traps, see Chapter 11, Understanding Traps.

Configuration MIBs

The SRC software has a limited number of MIB variables that can be set, such as variables to shut down or start components.

MIB Structure

The SNMP agent MIB uses the following Juniper Networks MIBs:

MIB Location

The MIBs are located in the SRC software distribution in the /SDK/mibs folder or on the Juniper Networks Web site at

http://www.juniper.net/techpubs/software/management/src

The default SNMP agent installation places the MIBs in the /opt/UMC/agent/mibs folder.

IOR Files

An SRC component writes its object references to an interoperable object reference (IOR) file, and the SNMP agent discovers components by monitoring IOR files.

SRC components have a property called sysman.iordirectory that specifies the location of the IOR file for the component. The default value for the location is the var folder relative to the SNMP agent folder (/opt/UMC/agent/var). If you install the SNMP agent in a folder other than the default, or if you previously changed the sysman.iordirectory property to a folder other than /opt/UMC/agent/var, you need to change the property so that it points to the folder where the IOR file currently resides.

The following sections provide the location and name of the property file for each component.

SNMP Agent

Use this information to access the SNMP agent property file and change the location of the IOR file.

You can change the location of the IOR file for the SNMP agent with the local configuration tool for the SNMP agent. Set this property in the Sysman Agent IOR Directory field.

See SRC-PE Getting Started Guide, Chapter 36, Configuring and Starting the SDX SNMP Agent on a Solaris Platform.

SAE

Use this information to access the SAE property file and change the location of the IOR file.

You can change the location of the IOR file for the SAE with the local configuration tool for the SAE. Set this property in the Sysman Agent IOR Directory field.

See SRC-PE Getting Started Guide, Chapter 35, Setting Up an SAE on a Solaris Platform.

License Server

Use this information to access the license server property file and change the location of the IOR file.

You can change the location of the IOR file for the license with the local configuration tool for the license server. Set this property in the Sysman Agent IOR Directory field.

For information about license server, see SRC-PE Getting Started Guide, Chapter 13, Managing the SRC License Server on Solaris Platforms.

NIC Host

Use this information to access the network information collector (NIC) property file and change the location of the IOR file.

You can also change the location of the IOR file for the NIC host with the local configuration tool for the NIC. Set this property in the Sysman IOR field.

For information about NIC hosts, see SRC-PE Network Guide, Chapter 11, Configuring NIC on a Solaris Platform.

Web Redirector

Use this information to access the Web redirector property file and change the location of the IOR file.


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