Dell EMC SmartFabric OS10 User Guide Release 10.5.1

VLT domain

A VLT domain includes the VLT peer devices, VLTi, and all VLT port channels that connect to the attached devices. It is also the configuration mode that you must use to assign VLT global parameters.

• Each VLT domain must have a unique MAC address that you create or that VLT creates automatically.
• VLAN ID 4094 is reserved as an internal control VLAN for the VLT domain. IPv6 addressing is used on this control VLAN for VLT peer-to-peer communication.
• ARP, IPv6 neighbors, and MAC tables synchronize between the VLT peer nodes.
• VLT peer devices operate as separate nodes with independent control and data planes for devices that attach to non-VLT ports.
• One node in the VLT domain takes a primary role, and the other node takes the secondary role. In a VLT domain with two nodes, the VLT assigns the primary node role to the node with the lowest MAC address by default. You can override the default primary election mechanism by assigning priorities to each node using the primary-priority command.
• If the primary peer fails, the secondary peer takes the primary role. If the primary peer (with the lower priority) later comes back online, it is assigned the secondary role (there is no preemption).
• In a VLT domain, the peer network devices must run the same OS10 software version.
  NOTE: A temporary exception is allowed during the upgrade process. See the Dell EMC SmartFabric OS 10.5.0.x Release Notes for more information.
• Configure the same VLT domain ID on peer devices. If a VLT domain ID mismatch occurs on VLT peers, the VLTi does not activate.
• In a VLT domain, VLT peers support connections to network devices that connect to only one peer.
• When you configure a VLT domain, the system generates a VLT Unit-ID. You cannot change the VLT Unit-ID. To identify the VLT node in a VLT domain, use the show vlt command.