Cisco Catalyst 4500 Series Administration Guide

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Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)SG
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Chapter 5 Configuring Virtual Switching Systems
Understanding Virtual Switching Systems
Understanding Virtual Switching Systems
These sections describe a VSS:
• VSS Overview, page 5-2
• VSS Redundancy, page 5-11
• Multichassis EtherChannels, page 5-14
• Packet Handling, page 5-16
• System Monitoring, page 5-20
• Dual-Active Detection, page 5-23
• Configuring a Recovery IP Address, page 5-25
• VSS Initialization, page 5-26
VSS Overview
Network operators increase network reliability by configuring switches and by provisioning links to the
redundant pairs. Figure 5-1 shows a typical switch network configuration. Redundant network elements
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 Typical Switch Network Design
The following sections present an overview of the VSS. These topics are covered in detail in subsequent
chapters:
• Key Concepts, page 5-3
• VSS Functionality, page 5-5
Access
Distribution
Core
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Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E