Description

This article discusses the 'isisRejectedAdjacency' trap in Junos OS.

Symptoms

In SNMP traces ISIS trap, the following is seen: 

snmpd[0]  <<<   OID  : snmpTrapOID.0
snmpd[0]  <<<   type : Object
snmpd[0]  <<<   value: isisRejectedAdjacency
snmpd[0]  <<<
snmpd[0]  <<<   value: isisRejectedAdjacency

Relevant log message in ISIS traces:

ERROR: <*> : IIH with on interface  

Solution

Check for configuration mismatches and possible loops in case of Duplicate SystemID.

If ISIS adjacency is rejected due to any of the following reasons and the error messages are seen in ISIS trace options, then SNMP will send an 'isisRejectedAdjacency' trap.

  1. Duplicate SystemID due to configuration mistake or ISIS hello packet loop:
    Error Message:
    ERROR: ISIS ignored a bad packet: IIH with duplicate sysid on interface ge-0/0/0.

  2. Area ID mismatch 
    Error message:
    ERROR: IIH from R2_re with no matching areas, interface

  3. Level Mismatch 
    Error message:
    ERROR: IIH from R2_re with no matching level, interface , circuit type <*>

  4. Interface type Mismatch 
    Error Message:
    ERROR: ISIS set layer2-map : interface disabled, 100.100.12.2, interface ge-0/0/0.0, SNPA 56:68:a3:1e:42:a8

  5. Authentication issue
    Error Message:
    ERROR: IIH from R1_re on ge-0/0/0.0 without authentication <-- When there is no authentication configured on Neighbor
    ERROR: IIH from R2_re on ge-0/0/0.0 failed authentication  <-- When there is authentication key mismatch