1.2.2 Issuing SNMP traps
SNMP Agent sends a change event in the agent system as an SNMP trap to the manager. The following figure shows an overview of SNMP trap issuance.
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![[Figure]](GRAPHICS/ZU010120.GIF)
At startup, or when an invalid SNMP request is received, SNMP Agent creates an SNMP trap message and sends it to the manager. SNMP trap messages sent over IPv4 support SNMPv1. SNMP trap messages sent over IPv6 support SNMPv1 and SNMPv2c.
- Note
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The user can specify which SNMP traps are to be considered important and displayed as alarms at the manager. This enables the user to easily monitor the alarms displayed at the manager and take appropriate actions to maintain normal network operation.
The following describes SNMP traps.
- Organization of this subsection
(1) Standard trap numbers of SNMPv1 traps
The two types of SNMPv1 traps are generic traps and enterprise-specific traps. These SNMPv1 traps are described in RFC 1157 as follows:
- Generic trap
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A trap identified by a standard trap number from 0 to 5, as stipulated in RFC 1157
- Enterprise-specific traps
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A trap identified by a combination of the standard trap number 6, stipulated in RFC 1157, and a user-specific trap number
The following table shows the list of SNMPv1 trap types and standard trap numbers.
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SNMPv1 trap type |
Standard trap number |
Description |
|---|---|---|
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Generic trap# |
0 |
coldStart |
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1 |
warmStart |
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2 |
linkDown |
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3 |
linkUp |
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4 |
authenticationFailure |
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5 |
egpNeighborLoss |
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Enterprise-specific traps |
6 |
enterpriseSpecific |
- #
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SNMP Agent issues only the coldStart generic trap and the authenticationFailure generic trap. It does not issue any other generic traps.
This subsection describes generic traps. For details about enterprise-specific traps, see 1.2.3(2) Definition of enterprise-specific traps.
(2) Agent address at the time of SNMP trap issuance
If the SNMPv1 trap is issued when IPv4 is being used, the agent address (the value stored in the Agent Address field of the SNMPv1 trap PDU) is the IPv4 address of the machine on which SNMP Agent is installed. You can obtain it by converting the host name to the IP address using the applicable system's OS functions.
If the SNMPv1 trap is issued when IPv6 is being used, the agent address is set to the following IPv4 address.
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Condition |
Value |
|---|---|
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Default |
0.0.0.0 |
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Destination address is ::1 |
127.0.0.1 |
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Destination address is an IPv4-mapped address, and -ip_proto is not ipv6. |
Determined by obtaining the host name using the function provided by the OS and converting it to an IPv4 address using the function provided by the OS. |
If the value of the agent address is 0.0.0.0, the trap might not be handled correctly. For example, if the manager references this field and determines that the trap is from the unknown IP address 0.0.0.0, it will not be able to handle the trap properly. In this case, one solution might be to issue an SNMPv2c trap. For details about the settings to use for issuing SNMPv2c traps over IPv6, see 2.8 IPv6 settings.
(3) Enterprise ID
The following table lists the enterprise IDs that are set in SNMPv1 traps.
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Even if SNMP Agent and NNMi coexist in the system, an enterprise ID ending with 3 is set.
The value of sysObjectID in the System group that is the standard MIB object of SNMP Agent is set as the enterprise ID in SNMPv1 traps.
- Note
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If you need to set events for the SNMP trap at the manager, use the enterprise ID that is set in the SNMP trap issued by SNMP Agent. For NNM events, SNMP trap information reported from SNMP Agent is set.
(4) Object IDs of SNMPv2c traps
The only SNMPv2c traps issued by SNMP Agent when IPv6 is being used are the coldStart trap and the authenticationFailure trap.
The following table lists the object IDs of the SNMPv2c traps.
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Object ID of SNMPv2c trap |
Meaning |
|---|---|
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.1.3.6.1.6.3.1.1.5.1 |
coldStart |
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.1.3.6.1.6.3.1.1.5.5 |
authenticationFailure |