Command Reference Guide

Virtual Link Trunking (VLT) | 1475

Virtual Link Trunking (VLT)

Overview

Virtual Link Trunking (VLT) is supported on the platform.

Virtual link trunking (VLT) allows physical links between two chassis to appear as a single

virtual link to the network core or other switches such as Edge, Access or ToR. VLT reduces

the role of Spanning Tree protocols by allowing LAG terminations on two separate

distribution or core switches, and by supporting a loop free topology. (A Spanning Tree

protocol is still needed to prevent the initial loop that may occur prior to VLT being

established. After VLT is established, RTSP may be used to prevent loops from forming with

new links that are incorrectly connected and outside the VLT domain.) VLT provides Layer 2

multipathing, creating redundancy through increased bandwidth, enabling multiple parallel

paths between nodes and load-balancing traffic where alternative paths exist.

Prerequisites: Before you configure VLT, make sure that both VLT peer switches are running

the same FTOS version and are configured for RSTP as described in the Virtual Link

Trunking (VLT) chapter in the FTOS Configuration Guide.

Commands

• back-up

• back-up destination

• clear vlt statistics

• delay-restore

• lacp ungroup member-independent

• peer-link

• peer-link port-channel

• primary-priority

• show vlt

• show vlt backup-link

• show vlt counter

Caution: Dell Force10 recommends not enabling Stacking and VLT simultaneously.

If both are enabled at the same time, unexpected behavior will occur.