Vlt On Core Switches; Enhanced Vlt - Dell S6000–ON Configuration Manual

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Figure 126. Example of VLT Deployment

VLT 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 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 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.

An enhanced VLT (eVLT) configuration creates a port channel between two VLT domains by allowing two

different VLT domains, using different VLT domain ID numbers, connected by a standard link aggregation

control protocol (LACP) LAG to form a loop-free Layer 2 topology in the aggregation layer.

This configuration supports a maximum of four switches, increasing the number of available ports and

allowing for dual redundancy of the VLT. The following example shows how the core/aggregation port

density in the Layer 2 topology is increased using eVLT. For inter-VLAN routing and other Layer 3 routing,

you need a separate Layer 3 router.

Virtual Link Trunking (VLT)