isisProtocolsSupportedMismatch

ISIS-MIB::isisProtocolsSupportedMismatch #

A notification sent when a non-pseudonode segment 0 LSP is received that has no matching protocols supported. This may be because the system does not generate the field, or because there are no common elements. The list of protocols supported should be included in the notification: it may be empty if the TLV is not supported, or if the TLV is empty. The agent must throttle the generation of consecutive isisProtocolsSupportedMismatch notifications so that there is at least a 5-second gap between notifications of this type. When notifications are throttled, they are dropped, not queued for sending at a future time.

Variables #

  • isisNotificationSysLevelIndex
  • isisNotificationCircIfIndex
  • isisPduProtocolsSupported
  • isisPduLspId
  • isisPduFragment

Definitions #

isisNotificationSysLevelIndex
The system level for this notification.
isisNotificationCircIfIndex
The identifier of this circuit relevant to this notification.
isisPduProtocolsSupported
The list of protocols supported by an adjacent system. This may be empty.
isisPduLspId
An Octet String that uniquely identifies a Link State PDU.
isisPduFragment
Holds up to 64 initial bytes of a PDU that triggered the notification.

Here is a runbook for the SNMP Trap description:

Meaning #

The ISIS-MIB::isisProtocolsSupportedMismatch notification is sent when a non-pseudonode segment 0 LSP is received with no matching protocols supported. This can occur when the system does not generate the field or when there are no common elements. The notification includes the list of protocols supported, which may be empty if the TLV is not supported or if the TLV is empty.

Impact #

This notification may indicate a mismatch in the ISIS protocols supported between two systems, which can lead to issues in the network topology and routing. This can cause problems with network convergence, stability, and performance. It is essential to investigate and resolve this issue to ensure the reliable operation of the network.

Diagnosis #

To diagnose the issue, follow these steps:

  1. Check the isisNotificationSysLevelIndex and isisNotificationCircIfIndex variables to identify the system and circuit interface involved.
  2. Examine the isisPduProtocolsSupported variable to determine the list of protocols supported by the adjacent system.
  3. Verify the isisPduLspId and isisPduFragment variables to identify the specific LSP and PDU that triggered the notification.
  4. Check the network configuration and ISIS protocol settings to ensure that they match between the involved systems.
  5. Analyze the network topology and routing tables to identify any potential issues or inconsistencies.

Mitigation #

To mitigate the issue, follow these steps:

  1. Verify that all systems in the network have the same ISIS protocol settings and configurations.
  2. Check for any software or firmware issues that may be causing the mismatch and apply any necessary updates.
  3. Ensure that the network topology and routing tables are up-to-date and consistent across all systems.
  4. If the issue persists, consider isolating the problematic segment or circuit to prevent further impact on the network.
  5. Monitor the network closely for any further notifications or issues related to ISIS protocol mismatches.
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