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 5, Understanding Traps.
Configuration MIBs
The SDX 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:
- Juniper-SDX-DES-MIB—Directory eventing system MIB
- Juniper-SDX-LICENSE-MIB—Licensing MIB
- Juniper-SDX-MIB—Main Juniper Networks SDX MIB
- Juniper-SDX-MIBS—Collection of Juniper Networks SDX MIB modules
- Juniper-SDX-POM-MIB—Policy management MIB
- Juniper-SDX-REDIRECTOR-MIB—Redirector MIB
- Juniper-SDX-SAE-MIB—SAE MIB
- Juniper-SDX-TC-MIB—Textual conventions MIB
- Juniper-SDX-TRAP-MIB—SDX trap definition MIB
- Juniper-SDX-WORKFLOW-MIB—Workflow MIB
- Juniper-UNI-SMI—Base SMI MIB
- Juniper-SDX-GW-MIB—Gateway applications MIB (includes the NIC MIB)
MIB Location
The MIBs are located in the SDX software distribution in the /SDK/mibs folder or on the Juniper Networks Web site at
http://www.juniper.net/techpubs/software/management/sdxThe default SNMP agent installation places the MIBs in the /opt/UMC/agent/mibs folder.