ISIS-STD_1.3.6.1.2.1.138.0.12 isisAreaMismatch

Description

ISIS-STD/3/AREA_MISMATCH:OID [oid] IS-IS received a level-1 Hello PDU whose area address is different from the local area address. (CircIfIndex=[integer], PduFragment=[opaque])

The area address contained in a received Level-1 Hello packet was different from the local one.

Attribute

Alarm ID	Alarm Severity	Alarm Type
1.3.6.1.2.1.138.0.12	Minor	environmentalAlarm(6)

Parameters

Name	Meaning
oid	Indicates the MIB object ID of the alarm.
CircIfIndex	Interface index
PduFragment	64-byte PDU header

Impact on the System

1. If the trap is triggered by a hardware fault on a board, route flapping may occur, and the CPU usage will increase.

2. If the trap is triggered by incorrect configurations, IS-IS neighbor relationships cannot be established, and routes cannot be learned from each other.

Possible Causes

Cause 1: Configurations were incorrect.

Cause 2: The area address field was modified.

Procedure

Based on the IS-IS packet format defined in ISO10589, check the pdu-fragment field (in hexadecimal) and obtain the system ID of the source wireless access controller. Run the display this command in the IS-IS view of the source wireless access controller to check whether the source wireless access controller is configured with an area address the same as that of the local wireless access controller.

If the area addresses are the same, go to Step 3.
If the area addresses are different, go to Step 2.

**Table 1** Methods of identifying system IDs and types of IS-IS packets
Identifying the Packet Type	Identifying the System ID
Hello: A Hello packet is identified when the 5th byte in the pdu-fragment field is 0f, 10, or 11.	The six consecutive bytes beginning with the 10th byte in the PduFragment field constitute a System ID.
LSP: An LSP is identified when the 5th byte in the pdu-fragment field is 12 or 14.	The six consecutive bytes beginning with the 13th byte in the pdu-fragment field constitute a System ID.
SNP: An SNP is identified when the 5th byte in the pdu-fragment field is 18, 19, 1A, or 1B.	The six consecutive bytes beginning with the 11th byte in the pdu-fragment field constitute a System ID.

Run the network-entity command in the IS-IS view of the source wireless access controller to configure an IS-IS area address the same as that of the local wireless access controller. Exercise caution when using the undo network-entity command. Then check whether the trap is cleared.
- If the trap is cleared, go to Step 4.
- If the trap is not cleared, go to Step 3.
Collect alarm information and configuration information, and then contact technical support personnel.
End.

Related Information

None