Cisco cluster switch ISL ports down due to faulty switch port
Applies to
- ONTAP 9
- Cisco N9K-C9336C-FX2 Cluster Switches
Issue
- The following ISL down alerts are reported in the event logs for both cluster switches:
[Node-01: cshmd: hm.alert.raised:alert]: Alert Id = SwitchIslIfDownWarn_Alert , Alerting Resource = Cluster_sw1(FDOXXXXXXXX)/Ethernet1/36 raised by monitor ethernet-switch
[Node-01: cshmd: hm.alert.raised:alert]: Alert Id = SwitchIslIfDownWarn_Alert , Alerting Resource = Cluster_sw2(FDOXXXXXXXH)/Ethernet1/36 raised by monitor ethernet-switch
- The system health alert reports the below information:
::> system health alert show
Node: Node-01
Alert ID: SwitchIslIfDownWarn_Alert
Resource: Ethernet1/36
Severity: Major
Indication Time: Tue Jan 14 05:29:26 2025
Suppress: false
Acknowledge: false
Probable Cause: The cable attached to the ISL port
"Cluster_sw1(FDOXXXXXXXX)/Ethernet1/36" with the
description of "Intra-Cluster Switch ISL Port 1/36
(port channel)" might be faulty. For the port-channel,
please check each individual link.
Possible Effect: Inter- or Intra- cluster redundancy might be lost.
Corrective Actions: 1) Check whether the cable is fully inserted into the interface port on both ends.
2) Reconnect the ISL port using another cable. After
reconnecting it, verify whether the link of the ISL
port is up by executing the commands per the switch
configuration guide or by checking whether the Link
status LED is on.
- The switch health is degraded because of this.
- The ISL port status shows down in the switch logs:
Cluster_sw1
`show interface brief`
--------------------------------------------------------------------------------
Ethernet VLAN Type Mode Status Reason Speed Port
Interface Ch #
--------------------------------------------------------------------------------
Eth1/36 1 eth trunk down Link not connected auto(D) 1
Cluster_sw2
`show interface brief`
--------------------------------------------------------------------------------
Ethernet VLAN Type Mode Status Reason Speed Port
Interface Ch #
--------------------------------------------------------------------------------
Eth1/36 1 eth trunk down Link not connected auto(D) 1
-
In some cases, the trasceivers may be reported as unsupported:
`show logging log`
SW1 %ETHPORT-3-IF_UNSUPPORTED_TRANSCEIVER: Transceiver on interface Ethernet1/35 is not supported
SW2 %ETHPORT-3-IF_UNSUPPORTED_TRANSCEIVER: Transceiver on interface Ethernet1/35 is not supported
- However, the cable used is supported as per the hardware universe.
- Replacement of the SFP/cable between the affected ISL ports of the switches does not resolve the issue.