OSPF_1.3.6.1.4.1.2011.5.25.155.31.36 hwOspfv2RouteLoopDetected

Trap Buffer Description

The local device has detected an OSPF routing loop. (LoopType=[LoopType], DetectProtocolAttr=[DetectProtocolAttr], RedistributeID1=[RedistributeID1], RedistributeID2=[RedistributeID2])

The device detects an OSPF routing loop.

In VS mode, this trap is supported only by the admin VS.

Trap Attributes

Trap Attribute	Description
Alarm or Event	Alarm
Trap Severity	Alert
Mnemonic Code	ospfRouteLoopDetected
Trap OID	1.3.6.1.4.1.2011.5.25.155.31.36
MIB	HUAWEI-OSPFV2-MIB
Alarm ID	0x00f10130
Alarm Name	ospfRouteLoopDetected
Alarm Type	communicationsAlarm
Raise or Clear	Raise
Match trap	OSPF_1.3.6.1.4.1.2011.5.25.155.31.37 hwOspfv2RouteLoopDetectedClear

Trap Buffer Parameters

Parameter	Description
LoopType	Loop detection type.
DetectProtocolAttr	Information about the loop detection protocol.
RedistributeID1	Re-advertisement device ID 1.
RedistributeID2	Re-advertisement device ID 2.

VB Parameters

VB OID	VB Name	VB Index
1.3.6.1.4.1.2011.5.25.155.30.27	hwOspfv2LoopDetectType	-
1.3.6.1.4.1.2011.5.25.155.30.28	hwOspfv2LoopDetectProtocolAttr	-
1.3.6.1.4.1.2011.5.25.155.30.29	hwOspfv2LoopDetectRedistributeID1	-
1.3.6.1.4.1.2011.5.25.155.30.30	hwOspfv2LoopDetectRedistributeID2	-

Impact on the System

A routing loop occurs, and services carried on the route are interrupted.

Possible Causes

Cause 1:
If the loop detection type is OSPF, the possible causes of the alarm are as follows:

RedistributeID1 and RedistributeID2 correspond to the router ID and process ID of the OSPF processes on the two devices where a routing loop occurs. When the OSPF processes on the two devices import routes from other OSPF processes, no import policy is configured or the import policy is incorrectly configured. As a result, a routing loop occurs.
Cause 2:
If the loop detection type is OSPF-ISIS, the possible causes of the alarm are as follows:

RedistributeID1 correspond to the System ID of the ISIS processes on the devices where a routing loop occurs, RedistributeID2 correspond to the router ID and process ID of the OSPF processes on the devices where a routing loop occurs. When the ISIS/OSPF processes on the two devices import routes from other OSPF/ISIS processes, no import policy is configured or the import policy is incorrectly configured. As a result, a routing loop occurs.
Cause 3:
If the loop detection type is OSPF-BGP, the possible causes of the alarm are as follows:

When the BGP/OSPF processes on the two devices import routes from other OSPF/BGP processes, no import policy is configured or the import policy is incorrectly configured. As a result, a routing loop occurs. RedistributeID2 correspond to the router ID and process ID of the OSPF processes on the devices where a routing loop occurs.

Procedure

Cause 1:
If the loop detection type is OSPF, the possible causes of the alarm are as follows:

RedistributeID1 and RedistributeID2 correspond to the router ID and process ID of the OSPF processes on the two devices where a routing loop occurs. When the OSPF processes on the two devices import routes from other OSPF processes, no import policy is configured or the import policy is incorrectly configured. As a result, a routing loop occurs.

After detecting a loop on an imported route, OSPF automatically increases the cost of the imported route to eliminate the impact of the loop on services.The original risk source of the routing loop caused by the re-advertisement of two devices still exists. In addition, the route cost adjusted by the system during automatic loop breaking may cause the traffic path to be inconsistent with the expected one. Therefore, after the system reports the alarm, modify the policy for importing routes in the OSPF process on the two devices that re-advertise routes as soon as possible to eliminate the configuration risk source that causes routing loops.You can run the display ospf process-id import-route loop-detect state command to view information about the routes that have formed a loop and are automatically broken. process-id is the process ID in the alarm information about the loop detection protocol.

After the risk source that causes the loop is eliminated, run the clear route loop-detect ospf alarm-state command in the system view of the device that generates the alarm to manually clear the alarm and restore the cost of the imported route to the normal value.
Cause 2:
If the loop detection type is OSPF-ISIS, the possible causes of the alarm are as follows:

RedistributeID1 correspond to the System ID of the ISIS processes on the devices where a routing loop occurs, RedistributeID2 correspond to the router ID and process ID of the OSPF processes on the devices where a routing loop occurs. When the ISIS/OSPF processes on the two devices import routes from other OSPF/ISIS processes, no import policy is configured or the import policy is incorrectly configured. As a result, a routing loop occurs.

After detecting a loop on an imported route, OSPF automatically increases the cost of the imported route to eliminate the impact of the loop on services. The original risk source of the routing loop caused by the re-advertisement of two devices still exists. In addition, the route cost adjusted by the system during automatic loop breaking may cause the traffic path to be inconsistent with the expected one. Therefore, after the system reports the alarm, modify the policy for importing routes in the IS-IS and OSPF processes on the two devices that re-advertise routes as soon as possible to eliminate the configuration risk source that causes routing loops. You can run the display ospf process-id import-route loop-detect state command to view information about the routes that have formed a loop and are automatically broken. process-id is the process ID in the alarm information about the loop detection protocol.

After the risk source that causes the loop is eliminated, run the clear route loop-detect ospf alarm-state command in the system view of the device that generates the alarm to manually clear the alarm and restore the cost of the imported route to the normal value.
Cause 3:
If the loop detection type is OSPF-BGP, the possible causes of the alarm are as follows:

When the BGP/OSPF processes on the two devices import routes from other OSPF/BGP processes, no import policy is configured or the import policy is incorrectly configured. As a result, a routing loop occurs. RedistributeID2 correspond to the router ID and process ID of the OSPF processes on the devices where a routing loop occurs.

After detecting a loop on an imported route, OSPF automatically increases the cost of the imported route to eliminate the impact of the loop on services. The original risk source of the routing loop caused by the re-advertisement of two devices still exists. In addition, the route cost adjusted by the system during automatic loop breaking may cause the traffic path to be inconsistent with the expected one. Therefore, after the system reports the alarm, modify the policy for importing routes in the BGP and OSPF processes on the two devices that re-advertise routes as soon as possible to eliminate the configuration risk source that causes routing loops. You can run the display ospf process-id import-route loop-detect state command to view information about the routes that have formed a loop and are automatically broken. process-id is the process ID in the alarm information about the loop detection protocol.

After the risk source that causes the loop is eliminated, run the clear route loop-detect ospf alarm-state command in the system view of the device that generates the alarm to manually clear the alarm and restore the cost of the imported route to the normal value.