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
OL-30933-01
Chapter 5 Configuring Virtual Switching Systems
In-Service Software Upgrade (ISSU) on a VSS
• automatically; using a single command
ISSU using the four-command sequence
The manual ISSU upgrade process involves issuing four distinct ISSU EXEC commands in sequence
• issu loadversion
• issu runversion
• issu acceptversion
• issu commitversion
A fifth command, issu abortversion, enables you to abort the ISSU upgrade process at any time, and to
revert to the initial system state.
These four commands take the VSS through a series of states that culminate in the Active and standby
supervisor engines running the post-upgrade IOS XE image. The VSS continues to operate throughout
the entire process; however as explained in Traffic and Network Protocol Disruption During ISSU in a
VSS, page 5-57, service is disrupted on network links that terminate on interfaces that reside in the
switch that is undergoing a reboot.
Figure 5-11 depicts the states through which the VSS Active and standby supervisor engines progress as
the sequence of four commands entered. It also shows the effect of the issu abortversion command at
any given point during the process.
Figure 5-11 States of VSS Active and Standby during Command Execution
A
Chassis running
the pre-upgrade
version
Chassis
undergoing
reboot
Chassis running
the post-upgrade
image
SSO Active
Switch.
A
A
A
A
A
A
A
A
A
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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