Cisco Catalyst 2960-XR User manual

Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS
Release 15.0(2)EX1
First Published: August 08, 2013
Americas Headquarters
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
USA
http://www.cisco.com
Tel: [phone]
800 553-NETS (6387)
Fax: [phone]
Text Part Number: OL-29424-01

THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS,
INFORMATION, AND RECOMMENDATIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE BUT ARE PRESENTED WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED. USERS MUST TAKE FULL RESPONSIBILITY FOR THEIR APPLICATION OF ANY PRODUCTS.
THE SOFTWARE LICENSE AND LIMITED WARRANTY FOR THE ACCOMPANYING PRODUCT ARE SET FORTH IN THE INFORMATION PACKET THAT SHIPPED WITH
THE PRODUCT AND ARE INCORPORATED HEREIN BY THIS REFERENCE. IF YOU ARE UNABLE TO LOCATE THE SOFTWARE LICENSE OR LIMITED WARRANTY,
CONTACT YOUR CISCO REPRESENTATIVE FOR A COPY.
The Cisco implementation of TCP header compression is an adaptation of a program developed by the University of California, Berkeley (UCB) as part of UCB's public domain version
of the UNIX operating system. All rights reserved. Copyright ©1981, Regents of the University of California.
NOTWITHSTANDING ANY OTHER WARRANTY HEREIN, ALL DOCUMENT FILES AND SOFTWARE OF THESE SUPPLIERS ARE PROVIDED “AS IS" WITH ALL FAULTS.
CISCO AND THE ABOVE-NAMED SUPPLIERS DISCLAIM ALL WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, THOSE OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OR ARISING FROM A COURSE OF DEALING, USAGE, OR TRADE PRACTICE.
IN NO EVENT SHALL CISCO OR ITS SUPPLIERS BE LIABLE FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR INCIDENTAL DAMAGES, INCLUDING, WITHOUT
LIMITATION, LOST PROFITS OR LOSS OR DAMAGE TO DATA ARISING OUT OF THE USE OR INABILITY TO USE THIS MANUAL, EVEN IF CISCO OR ITS SUPPLIERS
HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network
topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional
and coincidental.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: http://
www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership
relationship between Cisco and any other company. (1110R)
©2013 Cisco Systems, Inc. All rights reserved.

CONTENTS
Preface Preface xi
Document Conventions xi
Related Documentation xiii
Obtaining Documentation and Submitting a Service Request xiii
CHAPTER 1 Using the Command-Line Interface 1
Information About Using the Command-Line Interface 1
Command Modes 1
Using the Help System 3
Understanding Abbreviated Commands 4
No and default Forms of Commands 4
CLI Error Messages 4
Configuration Logging 5
How to Use the CLI to Configure Features 5
Configuring the Command History 5
Changing the Command History Buffer Size 6
Recalling Commands 6
Disabling the Command History Feature 7
Enabling and Disabling Editing Features 7
Editing Commands through Keystrokes 8
Editing Command Lines That Wrap 9
Searching and Filtering Output of show and more Commands 10
Accessing the CLI through a Console Connection or through Telnet 11
CHAPTER 2 Configuring Spanning Tree Protocol 13
Finding Feature Information 13
Restrictions for STP 13
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 iii

Information About Spanning Tree Protocol 14
Spanning Tree Protocol 14
Spanning-Tree Topology and BPDUs 15
Bridge ID, Device Priority, and Extended System ID 17
Port Priority Versus Path Cost 18
Spanning-Tree Interface States 18
Blocking State 19
Listening State 20
Learning State 20
Forwarding State 20
Disabled State 20
How a Switch or Port Becomes the Root Switch or Root Port 21
Spanning Tree and Redundant Connectivity 21
Spanning-Tree Address Management 22
Accelerated Aging to Retain Connectivity 22
Spanning-Tree Modes and Protocols 23
Supported Spanning-Tree Instances 23
Spanning-Tree Interoperability and Backward Compatibility 24
STP and IEEE 802.1Q Trunks 24
VLAN-Bridge Spanning Tree 24
Spanning Tree and Switch Stacks 25
Default Spanning-Tree Configuration 25
How to Configure Spanning-Tree Features 26
Changing the Spanning-Tree Mode 26
Disabling Spanning Tree 28
Configuring the Root Switch 29
Configuring a Secondary Root Device 30
Configuring Port Priority 31
Configuring Path Cost 32
Configuring the Device Priority of a VLAN 34
Configuring the Hello Time 35
Configuring the Forwarding-Delay Time for a VLAN 36
Configuring the Maximum-Aging Time for a VLAN 36
Configuring the Transmit Hold-Count 37
Monitoring Spanning-Tree Status 38
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
iv OL-29424-01
Contents

Additional References for Spanning-Tree Protocol 39
Feature Information for STP 40
CHAPTER 3 Configuring Multiple Spanning-Tree Protocol 41
Finding Feature Information 41
Prerequisites for MSTP 41
Restrictions for MSTP 42
Information About MSTP 43
MSTP Configuration 43
MSTP Configuration Guidelines 44
Root Switch 44
Multiple Spanning-Tree Regions 45
IST, CIST, and CST 46
Operations Within an MST Region 46
Operations Between MST Regions 47
IEEE 802.1s Terminology 47
Illustration of MST Regions 48
Hop Count 49
Boundary Ports 49
IEEE 802.1s Implementation 50
Port Role Naming Change 50
Interoperation Between Legacy and Standard Switches 50
Detecting Unidirectional Link Failure 51
MSTP and Switch Stacks 52
Interoperability with IEEE 802.1D STP 52
RSTP Overview 52
Port Roles and the Active Topology 53
Rapid Convergence 54
Synchronization of Port Roles 55
Bridge Protocol Data Unit Format and Processing 56
Processing Superior BPDU Information 57
Processing Inferior BPDU Information 57
Topology Changes 57
Protocol Migration Process 58
Default MSTP Configuration 58
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 v
Contents

How to Configure MSTP Features 59
Specifying the MST Region Configuration and Enabling MSTP 59
Configuring the Root Switch 62
Configuring a Secondary Root Switch 63
Configuring Port Priority 64
Configuring Path Cost 65
Configuring the Switch Priority 67
Configuring the Hello Time 68
Configuring the Forwarding-Delay Time 69
Configuring the Maximum-Aging Time 70
Configuring the Maximum-Hop Count 71
Specifying the Link Type to Ensure Rapid Transitions 72
Designating the Neighbor Type 73
Restarting the Protocol Migration Process 75
Monitoring MST Configuration and Status 76
Additional References for MSTP 76
Feature Information for MSTP 77
CHAPTER 4 Configuring Optional Spanning-Tree Features 79
Finding Feature Information 79
Restriction for Optional Spanning-Tree Features 79
Information About Optional Spanning-Tree Features 80
PortFast 80
BPDU Guard 80
BPDU Filtering 81
UplinkFast 82
Cross-Stack UplinkFast 83
How Cross-Stack UplinkFast Works 84
Events That Cause Fast Convergence 86
BackboneFast 86
EtherChannel Guard 89
Root Guard 89
Loop Guard 90
How to Configure Optional Spanning-Tree Features 90
Enabling PortFast 90
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
vi OL-29424-01
Contents

Enabling BPDU Guard 92
Enabling BPDU Filtering 93
Enabling UplinkFast for Use with Redundant Links 95
Disabling UplinkFast 96
Enabling BackboneFast 97
Enabling EtherChannel Guard 98
Enabling Root Guard 99
Enabling Loop Guard 100
Monitoring the Spanning-Tree Status 102
Additional References for Optional Spanning Tree Features 102
Feature Information for Optional Spanning-Tree Features 103
CHAPTER 5 Configuring EtherChannels 105
Finding Feature Information 105
Restrictions for EtherChannels 105
Information About EtherChannels 106
EtherChannel Overview 106
EtherChannel Modes 107
EtherChannel on Switches 108
EtherChannel Link Failover 109
Channel Groups and Port-Channel Interfaces 109
Port Aggregation Protocol 111
PAgP Modes 111
Silent Mode 112
PAgP Learn Method and Priority 112
PAgP Interaction with Virtual Switches and Dual-Active Detection 113
PAgP Interaction with Other Features 114
Link Aggregation Control Protocol 114
LACP Modes 114
LACP Interaction with Other Features 115
EtherChannel On Mode 115
Load-Balancing and Forwarding Methods 115
MAC Address Forwarding 116
IP Address Forwarding 116
Load-Balancing Advantages 117
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 vii
Contents

EtherChannel and Switch Stacks 118
Switch Stacks and PAgP 119
Switch Stacks and LACP 119
Default EtherChannel Configuration 119
EtherChannel Configuration Guidelines 120
Layer 2 EtherChannel Configuration Guidelines 122
Layer 3 EtherChannel Configuration Guidelines 123
How to Configure EtherChannels 123
Configuring Layer 2 EtherChannels 123
Configuring Layer 3 EtherChannels 126
Creating Port-Channel Logical Interfaces 126
Configuring the Physical Interfaces 127
Configuring EtherChannel Load-Balancing 129
Configuring the PAgP Learn Method and Priority 130
Configuring LACP Hot-Standby Ports 132
Configuring the LACP System Priority 132
Configuring the LACP Port Priority 133
Monitoring EtherChannel, PAgP, and LACP Status 135
Configuration Examples for Configuring EtherChannels 136
Configuring Layer 2 EtherChannels: Examples 136
Configuring Port-Channel Logical Interfaces: Example 136
Configuring EtherChannel Physical Interfaces: Examples 137
Additional References for EtherChannels 137
Feature Information for EtherChannels 138
CHAPTER 6 Configuring Link-State Tracking 139
Finding Feature Information 139
Restrictions for Configuring Link-State Tracking 139
Understanding Link-State Tracking 140
How to Configure Link-State Tracking 143
Monitoring Link-State Tracking 144
Configuring Link-State Tracking: Example 144
Additional References for Link-State Tracking 145
Feature Information for Link-State Tracking 146
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
viii OL-29424-01
Contents

CHAPTER 7 Configuring Flex Links and the MAC Address-Table Move Update Feature 147
Finding Feature Information 147
Restrictions for Configuring Flex Links and MAC Address-Table Move Update 147
Information About Flex Links and MAC Address-Table Move Update 148
Flex Links 148
Flex Links Configuration 149
VLAN Flex Links Load Balancing and Support 149
Multicast Fast Convergence with Flex Links Failover 150
Learning the Other Flex Links Port as the mrouter Port 150
Generating IGMP Reports 150
Leaking IGMP Reports 151
MAC Address-Table Move Update 151
Flex Links VLAN Load Balancing Configuration Guidelines 153
MAC Address-Table Move Update Configuration Guidelines 153
Default Flex Links and MAC Address-Table Move Update Configuration 153
How to Configure Flex Links and the MAC Address-Table Move Update Feature 154
Configuring Flex Links 154
Configuring a Preemption Scheme for a Pair of Flex Links 155
Configuring VLAN Load Balancing on Flex Links 157
Configuring MAC Address-Table Move Update 158
Configuring a Switch to Obtain and Process MAC Address-Table Move Update
Messages 159
Monitoring Flex Links and the MAC Address-Table Move Update 160
Configuration Examples for Flex Links 161
Configuring Flex Links: Examples 161
Configuring VLAN Load Balancing on Flex Links: Examples 161
Configuring the MAC Address-Table Move Update: Examples 163
Configuring Multicast Fast Convergence with Flex Links Failover: Examples 163
Additional References for Flex Links and MAC Address-Table Move Update 165
Feature Information for Flex Links and MAC Address-Table Move Update 166
CHAPTER 8 Configuring UniDirectional Link Detection 167
Finding Feature Information 167
Restrictions for Configuring UDLD 167
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 ix
Contents

Information About UDLD 168
Modes of Operation 168
Normal Mode 168
Aggressive Mode 168
Methods to Detect Unidirectional Links 169
Neighbor Database Maintenance 169
Event-Driven Detection and Echoing 169
UDLD Reset Options 170
Default UDLD Configuration 170
How to Configure UDLD 171
Enabling UDLD Globally 171
Enabling UDLD on an Interface 172
Monitoring and Maintaining UDLD 173
Additional References for UDLD 174
Feature Information for UDLD 175
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
xOL-29424-01
Contents

Preface
•Document Conventions, page xi
•Related Documentation, page xiii
•Obtaining Documentation and Submitting a Service Request, page xiii
Document Conventions
This document uses the following conventions:
DescriptionConvention
Both the ^symbol and Ctrl represent the Control (Ctrl) key on a keyboard. For
example, the key combination ^D or Ctrl-D means that you hold down the Control
key while you press the D key. (Keys are indicated in capital letters but are not
case sensitive.)
^ or Ctrl
Commands and keywords and user-entered text appear in bold font.bold font
Document titles, new or emphasized terms, and arguments for which you supply
values are in italic font.
Italic font
Terminal sessions and information the system displays appear in courier font.Courier font
Bold Courier font indicates text that the user must enter.Bold Courier font
Elements in square brackets are optional.[x]
An ellipsis (three consecutive nonbolded periods without spaces) after a syntax
element indicates that the element can be repeated.
...
A vertical line, called a pipe, indicates a choice within a set of keywords or
arguments.
|
Optional alternative keywords are grouped in brackets and separated by vertical
bars.
[x | y]
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 xi

DescriptionConvention
Required alternative keywords are grouped in braces and separated by vertical
bars.
{x | y}
Nested set of square brackets or braces indicate optional or required choices
within optional or required elements. Braces and a vertical bar within square
brackets indicate a required choice within an optional element.
[x {y | z}]
A nonquoted set of characters. Do not use quotation marks around the string or
the string will include the quotation marks.
string
Nonprinting characters such as passwords are in angle brackets.< >
Default responses to system prompts are in square brackets.[ ]
An exclamation point (!) or a pound sign (#) at the beginning of a line of code
indicates a comment line.
!, #
Reader Alert Conventions
This document may use the following conventions for reader alerts:
Means reader take note. Notes contain helpful suggestions or references to material not covered in the
manual.
Note
Means the following information will help you solve a problem.
Tip
Means reader be careful. In this situation, you might do something that could result in equipment damage
or loss of data.
Caution
Means the described action saves time. You can save time by performing the action described in the
paragraph.
Timesaver
Means reader be warned. In this situation, you might perform an action that could result in bodily
injury.
Warning
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
xii OL-29424-01
Preface
Document Conventions

Related Documentation
Before installing or upgrading the switch, refer to the switch release notes.Note
•Catalyst 2960-XR Switch documentation, located at:
http://www.cisco.com/go/cat2960xr_docs
•Cisco SFP and SFP+ modules documentation, including compatibility matrixes, located at:
http://www.cisco.com/en/US/products/hw/modules/ps5455/tsd_products_support_series_home.html
•Cisco Validated Designs documents, located at:
http://www.cisco.com/go/designzone
Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, submitting a service request, and gathering additional information,
see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco
technical documentation, at:
http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html
Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed
and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free
service and Cisco currently supports RSS version 2.0.
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 xiii
Preface
Related Documentation

Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
xiv OL-29424-01
Preface
Obtaining Documentation and Submitting a Service Request

CHAPTER 1
Using the Command-Line Interface
•Information About Using the Command-Line Interface, page 1
•How to Use the CLI to Configure Features, page 5
Information About Using the Command-Line Interface
Command Modes
The Cisco IOS user interface is divided into many different modes. The commands available to you depend
on which mode you are currently in. Enter a question mark (?) at the system prompt to obtain a list of commands
available for each command mode.
You can start a CLI session through a console connection, through Telnet, a SSH, or by using the browser.
When you start a session, you begin in user mode, often called user EXEC mode. Only a limited subset of
the commands are available in user EXEC mode. For example, most of the user EXEC commands are one-time
commands, such as show commands, which show the current configuration status, and clear commands,
which clear counters or interfaces. The user EXEC commands are not saved when the switch reboots.
To have access to all commands, you must enter privileged EXEC mode. Normally, you must enter a password
to enter privileged EXEC mode. From this mode, you can enter any privileged EXEC command or enter
global configuration mode.
Using the configuration modes (global, interface, and line), you can make changes to the running configuration.
If you save the configuration, these commands are stored and used when the switch reboots. To access the
various configuration modes, you must start at global configuration mode. From global configuration mode,
you can enter interface configuration mode and line configuration mode.
This table describes the main command modes, how to access each one, the prompt you see in that mode, and
how to exit the mode.
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 1

Table 1: Command Mode Summary
About This ModeExit MethodPromptAccess MethodMode
Use this mode to
•Change
terminal
settings.
•Perform basic
tests.
•Display
system
information.
Enter logout or
quit.
Switch>
Begin a session
using Telnet, SSH,
or console.
User EXEC
Use this mode to
verify commands
that you have
entered. Use a
password to protect
access to this mode.
Enter disable to
exit.
Switch#
While in user EXEC
mode, enter the
enable command.
Privileged EXEC
Use this mode to
configure
parameters that
apply to the entire
switch.
To exit to privileged
EXEC mode, enter
exit or end, or press
Ctrl-Z.
Switch(config)#
While in privileged
EXEC mode, enter
the configure
command.
Global
configuration
Use this mode to
configure VLAN
parameters. When
VTP mode is
transparent, you can
create
extended-range
VLANs (VLAN IDs
greater than 1005)
and save
configurations in the
switch startup
configuration file.
To exit to global
configuration mode,
enter the exit
command.
To return to
privileged EXEC
mode, press Ctrl-Z
or enter end.
Switch(config-vlan)#
While in global
configuration mode,
enter the vlan
vlan-id command.
VLAN
configuration
Use this mode to
configure
parameters for the
Ethernet ports.
To exit to global
configuration mode,
enter exit.
To return to
privileged EXEC
mode, press Ctrl-Z
or enter end.
Switch(config-if)#
While in global
configuration mode,
enter the interface
command (with a
specific interface).
Interface
configuration
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
2OL-29424-01
Using the Command-Line Interface
Command Modes

About This ModeExit MethodPromptAccess MethodMode
Line configuration Use this mode to
configure
parameters for the
terminal line.
To exit to global
configuration mode,
enter exit.
To return to
privileged EXEC
mode, press Ctrl-Z
or enter end.
Switch(config-line)#
While in global
configuration mode,
specify a line with
the line vty or line
console command.
Using the Help System
You can enter a question mark (?) at the system prompt to display a list of commands available for each
command mode. You can also obtain a list of associated keywords and arguments for any command.
SUMMARY STEPS
1. help
2. abbreviated-command-entry ?
3. abbreviated-command-entry <Tab>
4. ?
5. command ?
6. command keyword ?
DETAILED STEPS
PurposeCommand or Action
Obtains a brief description of the help system in any
command mode.
help
Example:
Switch# help
Step 1
Obtains a list of commands that begin with a particular
character string.
abbreviated-command-entry ?
Example:
Switch# di?
dir disable disconnect
Step 2
Completes a partial command name.
abbreviated-command-entry <Tab>
Example:
Switch# sh conf<tab>
Switch# show configuration
Step 3
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 3
Using the Command-Line Interface
Using the Help System

PurposeCommand or Action
Lists all commands available for a particular command
mode.
?
Example:
Switch> ?
Step 4
Lists the associated keywords for a command.
command ?
Example:
Switch> show ?
Step 5
Lists the associated arguments for a keyword.
command keyword ?
Example:
Switch(config)# cdp holdtime ?
<10-255> Length of time (in sec) that receiver
Step 6
must keep this packet
Understanding Abbreviated Commands
You need to enter only enough characters for the switch to recognize the command as unique.
This example shows how to enter the show configuration privileged EXEC command in an abbreviated form:
Switch# show conf
No and default Forms of Commands
Almost every configuration command also has a no form. In general, use the no form to disable a feature or
function or reverse the action of a command. For example, the no shutdown interface configuration command
reverses the shutdown of an interface. Use the command without the keyword no to reenable a disabled feature
or to enable a feature that is disabled by default.
Configuration commands can also have a default form. The default form of a command returns the command
setting to its default. Most commands are disabled by default, so the default form is the same as the no form.
However, some commands are enabled by default and have variables set to certain default values. In these
cases, the default command enables the command and sets variables to their default values.
CLI Error Messages
This table lists some error messages that you might encounter while using the CLI to configure your switch.
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
4OL-29424-01
Using the Command-Line Interface
Understanding Abbreviated Commands

Table 2: Common CLI Error Messages
How to Get HelpMeaningError Message
Reenter the command followed by
a question mark (?) without any
space between the command and
the question mark.
The possible keywords that you can
enter with the command appear.
You did not enter enough
characters for your switch to
recognize the command.
% Ambiguous command: "show
con"
Reenter the command followed by
a question mark (?) with a space
between the command and the
question mark.
The possible keywords that you can
enter with the command appear.
You did not enter all of the
keywords or values required by this
command.
% Incomplete command.
Enter a question mark (?) to display
all of the commands that are
available in this command mode.
The possible keywords that you can
enter with the command appear.
You entered the command
incorrectly. The caret (^) marks the
point of the error.
% Invalid input detected at
‘^’marker.
Configuration Logging
You can log and view changes to the switch configuration. You can use the Configuration Change Logging
and Notification feature to track changes on a per-session and per-user basis. The logger tracks each
configuration command that is applied, the user who entered the command, the time that the command was
entered, and the parser return code for the command. This feature includes a mechanism for asynchronous
notification to registered applications whenever the configuration changes. You can choose to have the
notifications sent to the syslog.
Only CLI or HTTP changes are logged.Note
How to Use the CLI to Configure Features
Configuring the Command History
The software provides a history or record of commands that you have entered. The command history feature
is particularly useful for recalling long or complex commands or entries, including access lists. You can
customize this feature to suit your needs.
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
OL-29424-01 5
Using the Command-Line Interface
Configuration Logging

Changing the Command History Buffer Size
By default, the switch records ten command lines in its history buffer. You can alter this number for a current
terminal session or for all sessions on a particular line. This procedure is optional.
SUMMARY STEPS
1. terminal history [size number-of-lines]
DETAILED STEPS
PurposeCommand or Action
Changes the number of command lines that the switch records during
the current terminal session in privileged EXEC mode. You can
configure the size from 0 through 256.
terminal history [size number-of-lines]
Example:
Switch# terminal history size 200
Step 1
Recalling Commands
To recall commands from the history buffer, perform one of the actions listed in this table. These actions are
optional.
The arrow keys function only on ANSI-compatible terminals such as VT100s.Note
SUMMARY STEPS
1. Ctrl-P or use the up arrow key
2. Ctrl-N or use the down arrow key
3. show history
DETAILED STEPS
PurposeCommand or Action
Recalls commands in the history buffer, beginning with the most recent command.
Repeat the key sequence to recall successively older commands.
Ctrl-P or use the up arrow key
Step 1
Returns to more recent commands in the history buffer after recalling commands
with Ctrl-P or the up arrow key. Repeat the key sequence to recall successively
more recent commands.
Ctrl-N or use the down arrow key
Step 2
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
6OL-29424-01
Using the Command-Line Interface
Configuring the Command History