This document provides reference architectures and configuration guidance using the Cisco Catalyst 6500's Virtual Switching System (VSS) 1440 within an enterprise data center. The classic hierarchical architectures presented in this guide position VSS technology and functionality at the aggregation and access layers of the data center network.

VSS technology allows for the grouping of two Cisco Catalyst 6500 switches into a single virtual switch. A VSS system provides physical infrastructure redundancy while simultaneously simplifying the logical topology of the datacenter.

The primary benefits of this logical grouping include the following:

• Increased operational efficiency of a simplified network leveraging virtualization
• Increased availability and forwarding performance via Inter-chassis Stateful Switchover (SSO) and Nonstop Forwarding (NSF)
• Increased availability and forwarding performance via Multichassis EtherChannel (MEC)