Dell Configuration Guide for the S4048–ON System 9.14.2.6

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 set up 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 example 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 EMC Networking recommends running the internal gateway protocol (IGP) on the VLTi VLAN to synchronize the L3 routing table across the two nodes on a VLT system.