65NOTE:• Disable SNMP logging in normal cases to prevent a large amount of SNMP logs from decreasing deviceperformance.• The total output size for the node field (MIB node name) and the value field (value of the MIB node) ineach log entry is 1024 bytes. If this limit is exceeded, the information center truncates the data in thefields.Configuring SNMP trapsIntroduction to SNMP trapsThe SNMP agent sends traps to inform the NMS of important events, such as a reboot.Traps fall into generic traps and vendor-specific traps. Available generic traps include authentication,coldstart, linkdown, linkup and warmstart. All other traps are vendor-defined.SNMP traps generated by a module are sent to the information center. You can configure the informationcenter to enable or disable outputting the traps from a module by their severity and set outputdestinations. For more information about the information center, see the chapter “Information centerconfiguration.”Enabling SNMP trapsEnable SNMP traps only when necessary. SNMP traps are memory-intensive and may affect deviceperformance.Follow these steps to enable traps:To do… Use the command… RemarksEnter system view system-view —Enable traps globallysnmp-agent trap enable [ arp rate-limit |configuration | default-route | flash | standard[ authentication | coldstart | linkdown | linkup |warmstart ]* | system ]RequiredBy default, all traps areenabled.Enter Layer 2 Ethernet portview, or VLAN interfaceviewinterface interface-type interface-number RequiredEnable link state traps enable snmp trap updown RequiredEnabled by default.NOTE:• To generate linkUp or linkDown traps when the link state of an interface changes, you must enable thelinkUp or linkDown trap function globally by using the snmp-agent trap enable [ standard [ linkdown| linkup ] * ] command and on the interface by using the enable snmp trap updown command.• After you enable a trap function for a module, whether the module generates traps also depends on theconfiguration of the module. For more information, see the configuration guide for each module.
