Juniper Hidden Command : set chassis cluster control-link-vlan enable

• One Node is upgraded from a version that is prior to or from Junos OS 10.2R2 to 10.4 or later.




• By default, the VLAN tag on the control port will be in the enabled state.




• The node on which RE has been replaced was downgraded/upgraded from a version after Junos OS 10.2R2 to the same version as the other node and does not join the cluster and goes into split brain; that is, the nodes do not see each other.

Sample Output on NODE-0:

{primary:node0}
root@> show chassis cluster information detail 
node0:
--------------------------------------------------------------------------
Redundancy mode:
    Configured mode: active-active
    Operational mode: active-active

Redundancy group: 0, Threshold: 255, Monitoring failures: none
    Events:
        Aug  5 16:51:18.773 : hold->secondary, reason: Hold timer expired
        Aug  5 16:51:34.789 : secondary->primary, reason: Only node present
Control link statistics:
    Control link 0:
        Heartbeat packets sent: 63115
        Heartbeat packets received: 0
        Heartbeat packet errors: 0
        Duplicate heartbeat packets received: 0
    Control recovery packet count: 0
    Sequence number of last heartbeat packet sent: 63114
    Sequence number of last heartbeat packet received: 0
Fabric link statistics:
    Probes sent: 63114
    Probes received: 0
    Probe errors: 0
    Probes not processed: 0             
    Probes dropped due to control link down: 0
    Probes dropped due to fabric link down: 0
    Sequence number of last probe sent: 63114
    Sequence number of last probe received: 0
Chassis cluster LED information:
    Current LED color: Red
    Last LED change reason: Peer node: node1 is not present
Control port tagging:
    Enabled 


{primary:node0}
root> show chassis cluster status
Cluster ID: 1
Node    Priority   Status  Preempt  Manual  failover
Redundancy group: 0,Failover count: 1
node0       1        primary  no  no
node1       0        lost     n/a n/a

Sample Output on NODE-1:

{primary:node1}
root> show chassis cluster information detail 
node1:
--------------------------------------------------------------------------
Redundancy mode:
    Configured mode: active-active
    Operational mode: active-active

Redundancy group: 0, Threshold: 255, Monitoring failures: none
    Events:
        Aug  5 16:50:52.904 : hold->secondary, reason: Hold timer expired
        Aug  5 16:56:38.711 : secondary->primary, reason: Remote yield (1/0)
Control link statistics:
    Control link 0:
        Heartbeat packets sent: 64212
        Heartbeat packets received: 337
        Heartbeat packet errors: 0
        Duplicate heartbeat packets received: 0
    Control recovery packet count: 0
    Sequence number of last heartbeat packet sent: 64210
    Sequence number of last heartbeat packet received: 361
Fabric link statistics:
    Probes sent: 64210
    Probes received: 0
    Probe errors: 0
    Probes not processed: 0             
    Probes dropped due to control link down: 0
    Probes dropped due to fabric link down: 0
    Sequence number of last probe sent: 64210
    Sequence number of last probe received: 0
Chassis cluster LED information:
    Current LED color: Red
    Last LED change reason: Peer node: node0 is not present
Control port tagging:
    Disabled

{primary:node1}
root> show chassis cluster status    
Cluster ID: 1 
Node    Priority   Status  Preempt  Manual failover 

Redundancy group: 0 , Failover count: 1    
node0       0         lost    n/a  n/a     
node1       1         primary no   no  
  

admin@host> show chassis cluster information detail
.
Control port tagging:
Disabled

admin@host> set chassis cluster control-link-vlan enable/disable

As VLAN tagging is disabled on the control port in versions that are later than Junos OS 10.2R2, it is recommended to disable tagging on both of the nodes.