Reference Guide

Virtual Link Trunking (VLT) | 951
VLT on Core Switches
VLT can also be deployed on core switches. Uplinks from servers to the access layer and from access layer
to the aggregation layer are bundled in LAG groups with end-to-end Layer 2 multipathing. This requires
“horizontal” stacking at the access layer and VLT at the aggregation layer such that all the uplinks from
servers to access and access to aggregation are in active-active load sharing mode. This example provides
the highest form of resiliency, scaling and load balancing in data center switching networks.
The following figure shows stacking at the access, VLT in aggregation, and Layer 3 at the core.
The aggregation layer is mostly in the L2/L3 switching/routing layer. For better resiliency in the
aggregation, Dell Networking recommends running the Internal Gateway Protocol on the VLTi VLAN to
synchronize the L3 routing table across the two nodes on a VLT system.