Virtual Link Trunking (Vlt); Overview - Dell S4048–ON Configuration Manual

61

Virtual Link Trunking (VLT)

Virtual link trunking (VLT) allows physical links between two Dell switches to appear as a single virtual link to the network core or other
switches such as Edge, Access, or top-of-rack (ToR). As a result, the two physical switches appear as a single switch to the connected
devices.

Overview

In a traditional switched topology as shown below, spanning tree protocols (STPs) are used to block one or more links to prevent loops in
the network. Although loops are prevented, bandwidth of all links is not effectively utilized by the connected devices.
Figure 134. Traditional switched topology
VLT not only overcomes this caveat, but also provides a multipath to the connected devices. In the example shown below, the two physical
VLT peers appear as a single logical device to the connected devices. As the connected devices consider the VLT peers as a single switch,
VLT eliminates STP-blocked ports. However, the two VLT devices are independent Layer2/Layer3 (L2/L3) switches for devices in the
upstream network.
976 Virtual Link Trunking (VLT)