Cisco Cisco 1700 2600 3600 3700 Series VPN Module Weißbuch
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Introduction
The Cisco Catalyst 6500 Series Virtual Switching System (VSS) allows the clustering of two or more physical
chassis together into a single, logical entity. This technology allows for enhancements in all areas of network
design, including high availability, scalability, management, and maintenance.
This paper explains the Cisco VSS technology, including its benefits and requirements.
Cisco Catalyst 6500 Series Virtual Switching System: An Overview
The Cisco Catalyst 6500 Series Virtual Switching System (VSS) allows the merging of two physical Cisco Catalyst
6500 Series switches together into a single, logically managed entity. Figure 1 graphically represents this concept,
where you can manage two Cisco Catalyst 6509 chassis as a single, 18-slot chassis after enabling Cisco Virtual
Switching System.
Figure 1. Cisco Virtual Switching System Physical to Logical Representation
The Virtual Switching System is created by converting two standalone Catalyst 6500 systems to a Virtual Switching
System. The conversion is a one-time process that requires a few simple configuration steps and a system reload.
Once the individual chassis reload, they are converted into the Virtual Switching System.
The Virtual Switching System is supported with specific hardware and software components, including the
Supervisor Engine 720-10G and the Supervisor Engine 2T.
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Cisco Catalyst 6500 Series Virtual Switching System Architecture
The Cisco Catalyst 6500 Series Virtual Switching System allows the combination of two switches into a single,
logical network entity from the network control plane and management perspectives. It uses Cisco IOS Stateful
Switchover (SSO) technology, as well as Non-Stop Forwarding (NSF) extensions to routing protocols, to provide a
single, logical switching and routing entity. To neighboring devices, the Cisco Virtual Switching System appears as
a single, logical switch or router.
Within the Cisco Virtual Switching System, one chassis is designated as the active virtual switch, and the other is
designated as the standby virtual switch. All control plane functions are centrally managed by the active supervisor
engine of the active virtual switch chassis, including:
1
See the “Hardware and Software Requirements” section of this document for details on all VSS hardware and software
requirements.