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Configure RSTP on VLT peers to prevent forwarding loopsVLT peer 1 (primary)
Dell_VLTpeer1(conf)#protocol spanning-tree rstp
Dell_VLTpeer1(conf-rstp)#no disable
Dell_VLTpeer1(conf-rstp)#bridge-priority 4096
Configure RSTP on VLT peers to prevent forwarding loopsVLT peer 2
(secondary)
Dell_VLTpeer2(conf)#protocol spanning-tree rstp
Dell_VLTpeer2(conf-rstp)#no disable
Dell_VLTpeer2(conf-rstp)#bridge-priority 8192
NOTE: When you remove the VLT configuration, RSTP is recommended as a backup solution to avoid spanningtree
loops. In this case, you can use the following RSTP default values:
hellotime: 2 seconds
forwarddelay: 15 seconds
maxage: 20
There is no additional performance gain on VLT, if you configure the RSTP values other than the default values.
Configuring VLT
To configure VLT, use the following procedure.
Prerequisites:
Before you begin, make sure that both VLT peer switches are running the same Dell EMC Networking OS version and are
configured for RSTP as described in the RSTP Configuration section. For VRRP operation, ensure that you configure VRRP
groups and L3 routing on each VLT peer as described in VLT and VRRP interoperability in the Configuration Notes section. To
configure VLT and create a VLT domain in which two switches are physically connected and treated as a single port channel by
access devices, configure the following settings on each VLT peer device.
1. Configure the VLT interconnect for the VLT domain. The primary and secondary switch roles in the VLT domain are
automatically assigned after you configure both sides of the VLTi.
NOTE:
If you use a third-party ToR unit, to avoid potential problems if you reboot the VLT peers, Dell EMC recommends
using static LAGs on the VLTi between VLT peers.
2. Enable VLT and create a VLT domain ID. VLT automatically selects a system MAC address.
3. Configure a backup link for the VLT domain.
4. (Optional) Manually reconfigure the default VLT settings, such as the MAC address and VLT primary/ secondary roles.
5. Connect the peer switches in a VLT domain to an attached access device (switch or server).
Configuring a VLT Interconnect
To configure a VLT interconnect, follow these steps.
1. Configure the port channel for the VLT interconnect on a VLT switch and enter interface configuration mode.
CONFIGURATION mode
interface port-channel id-number
Enter the same port-channel number configured with the peer-link port-channel command as described in Enabling
VLT and Creating a VLT Domain.
NOTE: To be included in the VLTi, the port channel must be in Default mode (no switchport or VLAN assigned).
2. Remove any IP address from the interface if already present.
INTERFACE PORT-CHANNEL mode
no ip address
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Virtual Link Trunking (VLT)