ISIS_1.3.6.1.3.37.2.0.5 isisIDLenMismatch

Description

ISIS/2/SYSID_MISMATCH:OID [oid] The ID length of received PDU is different from local configuration. (sysInstance=[integer], sysInstanceofLevel=[integer], sysLevel=[integer], sysInstanceofPduFieldLen=[integer], circIndex=[integer], ifIndex=[integer], pduFieldLen=[integer], circIfIndex=[integer], pduFrag=[opaque], ifName=[string])

The length of the system ID carried in the header of the received PDU, including all types of IS-IS packets, did not match the length of the system ID of the local switch.

Attribute

Alarm ID	Alarm Severity	Alarm Type
1.3.6.1.3.37.2.0.5	Major	other(1)

Parameters

Name	Meaning
oid	Indicates the MIB object ID of the alarm.
sysInstance	Indicates the ID of the IS-IS process.
sysInstanceofLevel	Indicates the ID of the IS-IS process.
sysLevel	Indicates the IS-IS level: 1: Level-1 2: Level-2
sysInstanceofPduFieldLen	Indicates the ID of the IS-IS process.
circIndex	Indicates the index of the interface.
ifIndex	Indicates the index of the interface.
pduFieldLen	Indicates the length of the received PDU.
circIfIndex	Indicates the IF index of the interface.
pduFrag	Indicates the fragment of 64-byte PDU header.
ifName	Indicates the name of the interface.

Impact on the System

1. If the trap is triggered because of a hardware fault on the board, route flapping may occur.

2. If the trap is triggered because of intercommunication between switch devices, neighbors cannot be established, or routes cannot be learnt from each other.

Possible Causes

1. The length of the system ID supported by other switch devices mismatch with the length of the system ID supported by the local switch.

2. The system ID Length field was modified during packet transmission.

Procedure

Based on the IS-IS packet format defined in ISO10589, search for the pdu-fragment field (in hexadecimal) in the trap and fetch the system ID of the source switch. Check whether the length of the system ID is neither 0 nor 6.

If so, go to Step 2.
If not, go to Step 3.

**Table 1** Methods of searching for system IDs and types of IS-IS packets
Searching for the Packet Type	Searching for the System ID
Hello: the 5th byte in the pdu-fragment field being 0f, 10, or 11	The system ID is continuous 6 bytes after the 10th byte in the pdu-fragment field
LSP: the 5th byte in the pdu-fragment field being 12 or 14	The system ID is continuous 6 bytes after the 13th byte in the pdu-fragment field
SNP: the 5th byte in the pdu-fragment field being 18, 19, 1A, or 1B	The system ID is continuous 6 bytes after the 11th byte in the pdu-fragment field

Modify the system ID length configured on the source switch to 6. Then, check whether the trap is cleared.
- If so, go to Step 4.
- If not, go to Step 3.
Collect the trap information, log information, and configuration of the switch, and contact technical support personnel.
End.

Related Information

None