Dell Configuration Guide for the S4048–ON System 9.14.2.6

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Troubleshooting VLT

To help troubleshoot different VLT issues that may occur, use the following information.

NOTE For information on VLT Failure mode timing and its impact, contact your Dell EMC Networking representative.

Table 1. Troubleshooting VLTTroubleshooting VLT
Description	Behavior at Peer Up	Behavior During Run Time	Action to Take
Bandwidth monitoring	A syslog error message and an SNMP trap is generated when the VLTi bandwidth usage goes above the 80% threshold and when it drops below 80%.	A syslog error message and an SNMP trap is generated when the VLTi bandwidth usage goes above its threshold.	Depending on the traffic that is received, the traffic can be offloaded inVLTi.
Domain ID mismatch	The VLT peer does not boot up. The VLTi is forced to a down state. A syslog error message and an SNMP trap are generated.	The VLT peer does not boot up. The VLTi is forced to a down state. A syslog error message and an SNMP trap are generated.	Verify the domain ID matches on both VLT peers.
Dell EMC Networking OS Version mismatch	A syslog error message is generated.	A syslog error message is generated.	Follow the correct upgrade procedure for the unit with the mismatched Dell EMC Networking OS version.
Remote VLT port channel status	N/A	N/A	Use the show vlt detail and show vlt brief commands to view the VLT port channel status information.
Spanning tree mismatch at global level	All VLT port channels go down on both VLT peers. A syslog error message is generated.	No traffic is passed on the port channels. A one-time informational syslog message is generated.	During run time, a loop may occur as long as the mismatch lasts. To resolve, enable RSTP on both VLT peers.
Spanning tree mismatch at port level	A syslog error message is generated.	A one-time informational syslog message is generated.	Correct the spanning tree configuration on the ports.
System MAC mismatch	A syslog error message and an SNMP trap are generated.	A syslog error message and an SNMP trap are generated.	Verify that the unit ID of VLT peers is not the same on both units and that the MAC address is the same on both units.
Unit ID mismatch	The VLT peer does not boot up. The VLTi is forced to a down state. A syslog error message is generated.	The VLT peer does not boot up. The VLTi is forced to a down state. A syslog error message is generated.	Verify the unit ID is correct on both VLT peers. Unit ID numbers must be sequential on peer units; for example, if Peer 1 is unit ID “0”, Peer 2 unit ID must be “1’.
Version ID mismatch	A syslog error message and an SNMP trap are generated.	A syslog error message and an SNMP trap are generated.	Verify the Dell EMC Networking OS software versions on the VLT peers is compatible. For more information, refer to the Release Notes for this release.
VLT LAG ID is not configured on one VLT peer	A syslog error message is generated. The peer with the VLT configured remains active.	A syslog error message is generated. The peer with the VLT configured remains active.	Verify the VLT LAG ID is configured correctly on both VLT peers.
VLT LAG ID mismatch	The VLT port channel is brought down. A syslog error message is generated.	The VLT port channel is brought down. A syslog error message is generated.	Perform a mismatch check after the VLT peer is established.