Displays IS-IS error statistics.
Privileged EXEC mode
IS-IS is supported only on devices based on the DNX chipset family. For a list of such devices, see "Supported Hardware".
| Output field | Description | 
|---|---|
| Area Mismatch | The number of times the device interface was unable to create a Level-1 adjacency with a neighbor because the device interface and the neighbor did not have any areas in common. | 
| Max Area Mismatch | The number of times the device received a PDU whose value for maximum number of area addresses did not match the device‘s value for maximum number of area addresses. | 
| System ID Length Mismatch | The number of times the device received a PDU whose ID field was a different length than the ID field length configured on the device. | 
| LSP Sequence Number Skipped | The number of times the device received an LSP with a sequence number that was more than 1 higher than the sequence number of the previous LSP received from the same neighbor. | 
| LSP Max Sequence Number Exceeded | The number of times the device attempted to set an LSP sequence number to a value higher than the highest number in the CSNP sent by the Designated IS. | 
| Level-1 Database Overload | The number of times the Level-1 state on the device changed from Waiting to On or from On to Waiting. 
 | 
| Level-2 Database Overload | The number of times the Level-2 state on the device changed from Waiting to On or from On to Waiting. 
 | 
| Our LSP Purged | The number of times the device received an LSP that was originated by the device itself and had age zero (aged out). | 
| PDU Drop Count | 
 | 
| CSNP Auth Failures | The number of CSNP Authentication failures recorded for Level-1 and Level-2. This counter will only be displayed if it has a value greater than zero. | 
| PSNP Auth Failures | The number of PSNP Authentication failures recorded for Level-1 and Level-2. This counter appears only if it has a value greater than 0. | 
| HELLO Auth Failures | The number of HELLO Authentication failures recorded for Level-1 and Level-2. This counter will only be displayed if it has a value greater than zero. | 
| Adjacency not found | The number of PDUs dropped at both Level-1 and Level-2 because there is no valid adjacency on the interface where they were received. This counter will only be displayed if it has a value greater than zero. | 
| Adjacency Level Mismatch | The number of PDUs dropped at both Level-1 and Level-2 because the adjacency from which the PDU is received has a different level than the PDU level. This counter will only be displayed if it has a value greater than zero. | 
| IS Level Mismatch | The number of PDUs dropped at both Level-1 and Level-2 because the IS-IS router level mismatches with the PDU level received. This counter will only be displayed if it has a value greater than zero. | 
| Length Too Short | The number of PDUs dropped at both Level-1 and Level-2 because the received PDU length is less than the standard PDU header length. This counter will only be displayed if it has a value greater than zero. | 
| Length Too Long | The number of PDUs dropped at both Level-1 and Level-2 because the received PDU length is greater than the MTU of the link. This counter will only be displayed if it has a value greater than zero. | 
| Max Area Check Failure | The number of PDUs dropped at both Level-1 and Level-2 because the received PDU has a maximum area count different than what is configured on this IS-IS router. This counter will only be displayed if it has a value greater than zero. | 
| Zero Checksum | The number of PDUs dropped at both Level-1 and Level-2 because the received PDU has a zero checksum. This counter will only be displayed if it has a value greater than zero. | 
| Checksum Mismatch | The number of PDUs dropped at both Level-1 and Level-2 because the received PDU has a checksum different than the computed checksum on the received PDU. This counter will only be displayed if it has a value greater than zero. | 
| Invalid Length | The number of PDUs dropped at both Level-1 and Level-2 because the received PDU has a different length than what is advertised in the PDU header. This counter will only be displayed if it has a value greater than zero. | 
The following example displays sample output from the show isis counts command.
device# show isis counts Area Mismatch: 0 Max Area Mismatch: 0 System ID Length Mismatch: 0 LSP Sequence Number Skipped: 0 LSP Max Sequence Number Exceeded: 0 Level-1 Database Overload: 0 Level-2 Database Overload: 0 Our LSP Purged: 0