isisLSPErrorDetected

ISIS-MIB::isisLSPErrorDetected #

This notification is generated when we receive an LSP with a parse error. The isisCircIfIndex holds an index of the circuit on which the PDU arrived. The isisPduFragment holds the start of the LSP, and the isisErrorOffset points to the problem. If the problem is a malformed TLV, isisErrorOffset points to the start of the TLV, and isisErrorTLVType holds the value of the type. If the problem is with the LSP header, isisErrorOffset points to the suspicious byte. The number of such LSPs is accumulated in isisSysStatLSPErrors.

Variables #

  • isisNotificationSysLevelIndex
  • isisPduLspId
  • isisNotificationCircIfIndex
  • isisPduFragment
  • isisErrorOffset
  • isisErrorTLVType

Definitions #

isisNotificationSysLevelIndex
The system level for this notification.
isisPduLspId
An Octet String that uniquely identifies a Link State PDU.
isisNotificationCircIfIndex
The identifier of this circuit relevant to this notification.
isisPduFragment
Holds up to 64 initial bytes of a PDU that triggered the notification.
isisErrorOffset
An offset to a problem in a PDU. If the problem is a malformed TLV, this points to the beginning of the TLV. If the problem is in the header, this points to the byte that is suspicious.
isisErrorTLVType
The type for a malformed TLV.

Meaning #

The ISIS-MIB::isisLSPErrorDetected trap notification is generated when a Link State Protocol Data Unit (LSP) with a parse error is received. This notification provides information about the circuit on which the PDU arrived, the start of the LSP, and the location and type of the error.

Impact #

The impact of this trap notification is that the LSP with a parse error cannot be processed, which may affect the integrity and accuracy of the link-state database. This can lead to incorrect routing decisions, network instability, and potential outages.

Diagnosis #

To diagnose the issue, the following steps can be taken:

  1. Check the isisNotificationCircIfIndex variable to identify the circuit on which the PDU arrived.
  2. Use the isisPduFragment variable to examine the initial bytes of the PDU that triggered the notification.
  3. Analyze the isisErrorOffset variable to determine the location of the error in the PDU.
  4. If the error is a malformed TLV, check the isisErrorTLVType variable to determine the type of TLV that is malformed.
  5. Review the isisSysStatLSPErrors variable to see how many LSPs with parse errors have been received.

Mitigation #

To mitigate the issue, the following steps can be taken:

  1. Investigate the circuit identified by isisNotificationCircIfIndex to determine if there are any issues with the circuit or the device attached to it.
  2. Check the device logs to see if there are any error messages related to the LSP reception.
  3. Verify that the device is configured correctly and that the LSPs being received are valid.
  4. If the error is a malformed TLV, check the device configuration to ensure that the TLV is correctly formatted.
  5. Implement measures to prevent LSPs with parse errors from being received, such as filtering or rate-limiting incoming LSPs.
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