Vss Overview - Cisco Catalyst 4500 Series Software Configuration Manual

Understanding Virtual Switching Systems
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VSS Overview

Network operators increase network reliability by configuring switches and by provisioning links to the
redundant pairs.
and redundant links can add complexity to network design and operation. Virtual switching simplifies
the network by reducing the number of network elements and hiding the complexity of managing
redundant switches and links.
A VSS combines a pair of Catalyst 4500 or 4500-X series switches into a single network element. The
VSS manages the redundant links, which externally act as a single port channel.
The VSS simplifies network configuration and operation by reducing the number of Layer 3 routing
neighbors and by providing a loop-free Layer 2 topology.
Figure 5-1
Access
Distribution
Core
The following sections present an overview of the VSS. These topics are covered in detail in subsequent
chapters:
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Key Concepts
The VSS incorporates the following key concepts:
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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
5-2
VSS Initialization, page 5-26
Figure 5-1 shows a typical switch network configuration. Redundant network elements
Typical Switch Network Design
Key Concepts, page 5-2
VSS Functionality, page 5-5
Hardware Requirements, page 5-8
Understanding VSL Topology, page 5-10
Virtual Switching System, page 5-3
VSS Active and VSS Standby Switch, page 5-3
Virtual Switch Link, page 5-3
Multichassis EtherChannel, page 5-4
Chapter 5 Configuring Virtual Switching Systems