Cisco Cisco Catalyst 6500 Series VSSE 720 with 10GE uplinks Information Guide

Q&A

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Virtual Switching System

What is a virtual switching system (VSS)?

A VSS is network system virtualization technology that pools multiple Cisco

Catalyst

6500 Series Switches

into one virtual switch, increasing operational efficiency, boosting nonstop communications, and scaling system

bandwidth capacity to 1.4 Tbps. At the initial phase, a VSS will allow two physical Cisco Catalyst 6500 Series

Switches to operate as a single logical virtual switch called a virtual switching system 1440 (VSS1440). (See

Figure 1.)

Figure 1. Virtual Switching System 1440 Compared to Traditional Network Design

What is a VSS1440?

VSS1440 refers to the VSS formed by two Cisco Catalyst 6500 Series Switches with the Virtual Switching

Supervisor 720-10GE. In a VSS, the data plane and switch fabric with capacity of 720 Gbps of supervisor

engine in each chassis are active at the same time on both chassis, combining for an active 1400-Gbps

switching capacity per VSS. Only one of the virtual switch members has the active control plane. Both chassis

are kept in sync with the interchassis Stateful Switchover (SSO) mechanism along with Nonstop Forwarding

(NSF) to provide nonstop communication even in the event of failure of one of the member supervisor engines

or chassis.

What are the benefits of VSS?

VSS offers superior benefits compared to traditional Layer 2/Layer 3 network design. Benefits can be grouped

into four main categories:

1. VSS increases operational efficiency by simplifying the network, reducing switch management overhead by at

least 50 percent.

●

Single point of management, IP address, and routing instance for the Cisco Catalyst 6500 virtual switch

◦

Single configuration file and node to manage. Removes the need to configure redundant switches twice

with identical policies.

◦

Only one gateway IP address is required per VLAN, instead of the three IP addresses per VLAN used

today.