Dell Configuration Guide for the S4048–ON System 9.14.2.5

Enabling VLT and Creating a VLT Domain

To enable VLT and create a VLT domain, use the following steps.

1. Enable VLT on a switch, then configure a VLT domain and enter VLT-domain configuration mode.
   CONFIGURATION mode
   vlt domain domain-id
   The domain ID range is from 1 to 1000.
   Configure the same domain ID on the peer switch to allow for common peering. VLT uses the domain ID to automatically create a VLT MAC address for the domain. If you do not configure the system explicitly, the system mac-address of the primary will be the VLT MAC address for the domain.
   To disable VLT, use the no vlt domain command.
   NOTE Do not use MAC addresses such as “reserved” or “multicast.”
2. Configure the IP address of the management interface on the remote VLT peer to be used as the endpoint of the VLT backup link for sending out-of-band hello messages.
   VLT DOMAIN CONFIGURATION mode
   back-up destination {ipv4-address | ipv6-address} [interval seconds] {vrf [management vrf-name | vrf-name]}
   NOTE If management VRF or any specific VRF is enabled on the system, then use the back-up destination command with vrf [management vrf-name | vrf-name]
   You can optionally specify the time interval used to send hello messages. The range is from 1 to 5 seconds.
3. Configure the port channel to be used as the VLT interconnect between VLT peers in the domain.
   VLT DOMAIN CONFIGURATION mode
   peer-link port-channel id-number
4. Enable peer routing.
   VLT DOMAIN CONFIGURATION mode
   peer-routing
   If you enable peer routing, a VLT node acts as the proxy gateway for its peer.
5. (Optional) After you configure a VLT domain on each peer switch and connect (cable) the two VLT peers on each side of the VLT interconnect, the system elects a primary and secondary VLT peer device (see Primary and Secondary VLT Peers). To configure the primary and secondary roles before the election process, use the primary-priority command. Enter a lower value on the primary peer and a higher value on the secondary peer.
   VLT DOMAIN CONFIGURATION mode
   primary-priority value
   The priority values are from 1 to 65535. The default is 32768.

   If the primary peer fails, the secondary peer (with the higher priority) 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).
6. (Optional) Prevent a possible loop during the bootup of a VLT peer switch or a device that accesses the VLT domain.
   CONFIGURATION mode
   lacp ungroup member-independent {vlt | port-channel port-channel-id}
   LACP on VLT ports (on a VLT switch or access device), which are members of the virtual link trunk, is not brought up until the VLT domain is recognized on the access device.
7. Repeat Steps 1 to 5 on the VLT peer switch to configure the IP address of this switch as the endpoint of the VLT backup link and to configure the same port channel for the VLT interconnect.