VMware ESXi and vSphere Cluster Management

Configure Interface Descriptions in Cisco IOS

Learn how to add, verify, replace, remove, and save Cisco IOS interface descriptions for routers and switches.

What Is an Interface Description?

An interface description is administrative text associated with a Cisco IOS interface. It documents the interface's purpose, destination, connected device, circuit, location, or role.

Descriptions improve operational visibility. An engineer reviewing a configuration can quickly understand whether a port connects to a WAN provider, a remote office, a distribution switch, a server, or another network device.

An interface description is only documentation. It does not change packet forwarding, interface operation, routing, switching, or security behavior. It is also locally significant: the text is meaningful on the Cisco device where it is configured and is not automatically applied to the neighboring device.

Cisco IOS Modes Used for Descriptions

Cisco IOS is the operating system and command-line environment used by many Cisco routers and switches. Configuration commands are organized into modes.

Privileged EXEC mode is commonly identified by a # prompt. It provides access to monitoring commands and configuration-entry commands. Global configuration mode applies device-wide settings and commonly uses a (config)# prompt. Interface configuration mode applies settings to one selected interface and commonly uses a (config-if)# prompt.

Mode	Typical Prompt	How It Is Reached	Relevant Action
Privileged EXEC	`Router#`	Log in, or enter `enable` from user EXEC mode	Begin configuration and run verification commands
Global configuration	`Router(config)#`	Enter `configure terminal`	Select an interface
Interface configuration	`Router(config-if)#`	Enter an `interface` command	Enter `description`, `no description`, and other interface settings

Add an Interface Description

To add a description, identify the intended physical or logical interface, enter its configuration submode, and issue the description command followed by clear text.

Router> enable
Router# configure terminal
Router(config)# interface FastEthernet0/1
Router(config-if)# description WAN to London
Router(config-if)# end
Router#

In this example, FastEthernet0/1 is labeled as a WAN connection to the London location. The interface identifier must match the interface on the device being configured. Depending on the platform, valid identifiers may include FastEthernet, GigabitEthernet, TenGigabitEthernet, Serial, Port-channel, VLAN, or other interface types.

Use a Specific Label

A useful description can identify the connected endpoint, purpose, provider circuit, location, VLAN or uplink role, and owner when appropriate.

Element	Example Content	Operational Benefit
Connected endpoint	`To DIST-SW-01`	Shows which neighboring device is expected
Purpose or role	`Uplink to distribution`	Explains how the interface is used
Location	`WAN to London`	Identifies the remote site
Provider or circuit reference	`ISP-A circuit 48271`	Helps with provider coordination and troubleshooting
Owner	`Voice team handoff`	Identifies the responsible team when appropriate

Avoid vague labels such as link or server when more identifying information is available. Cisco IOS supports interface descriptions of up to 240 characters, but concise and consistent wording is usually easier to read.

Verify the Description

Use show running-config to inspect the active configuration. Locate the interface heading and read the description line beneath it.

Router# show running-config
!
interface FastEthernet0/1
 description WAN to London
 ip address 203.0.113.2 255.255.255.252
!

The line description WAN to London belongs to the FastEthernet0/1 stanza because it appears below that interface heading and before the next configuration section.

Interface-oriented show commands can also help operators review interface labels, but the main configuration check is to confirm the description in the running configuration.

Replace or Remove a Description

Replace an Existing Description

Entering a new description in the same interface configuration mode replaces the previous description. You do not need to remove the old text first.

Router# configure terminal
Router(config)# interface FastEthernet0/1
Router(config-if)# description WAN to London - ISP-A circuit 48271

This is useful when a provider circuit, remote site, connected device, or interface role changes.

Remove a Description

Use the negated command no description from interface configuration mode to remove the existing label.

Router(config)# interface FastEthernet0/1
Router(config-if)# no description

Where IOS command abbreviation is accepted, no desc is an abbreviated form:

Router(config-if)# no desc

To remove an obsolete label from the wrong interface, select that interface first and then issue the removal command.

Save the Configuration

The running-config is the active configuration currently used by the device. A description entered at the command line changes the running configuration immediately.

The startup-config is the saved configuration loaded after a device reload. If the description must survive a reboot, save the active configuration:

Router# copy running-config startup-config

Confirm the intended interface and description before saving. A description that is not copied to startup-config can disappear after a reload.

Command Reference

Task	Command	Required Configuration Mode	Expected Result
Enter privileged EXEC mode	`enable`	User EXEC	Displays the privileged EXEC prompt
Enter global configuration mode	`configure terminal`	Privileged EXEC	Displays the `(config)#` prompt
Select an interface	`interface FastEthernet0/1`	Global configuration	Displays the `(config-if)#` prompt for that interface
Add or replace a description	`description WAN to London`	Interface configuration	Creates or replaces the interface label
Verify the active configuration	`show running-config`	Privileged EXEC	Displays the current configuration, including interface stanzas
Remove a description	`no description`	Interface configuration	Deletes the interface description
Use the abbreviated removal form	`no desc`	Interface configuration	Removes the description where the abbreviation is accepted
Save the active configuration	`copy running-config startup-config`	Privileged EXEC	Stores the current configuration for use after a reload

Practical Examples

Document a Switch Uplink

Identify both the neighboring device and the connection role:

Switch# configure terminal
Switch(config)# interface GigabitEthernet1/0/24
Switch(config-if)# description Uplink to DIST-SW-01

Update a Changed Circuit

If an interface previously described an old provider or site, replace the label with current information:

Router# configure terminal
Router(config)# interface Serial0/0/0
Router(config-if)# description WAN to Manchester - ISP-B circuit 77104

Remove an Obsolete Label

Switch# configure terminal
Switch(config)# interface GigabitEthernet1/0/12
Switch(config-if)# no description

Troubleshooting

The Description Command Is Rejected

The most likely cause is that you are not in interface configuration mode. Enter global configuration mode, select the correct interface, and then enter the description:

Router# configure terminal
Router(config)# interface FastEthernet0/1
Router(config-if)# description WAN to London

The Description Is on the Wrong Port

An incorrect interface identifier may have been selected. Use show running-config to find the incorrect interface stanza. Enter the intended interface and configure the correct text there, then select the unintended interface and use no description to remove the incorrect label.

The Description Disappeared After a Reload

The running configuration was probably not saved. Reapply or confirm the description, then use:

Router# copy running-config startup-config

The Description Is Out of Date

A circuit, connected device, location, or interface role may have changed without an accompanying documentation update. Replace the old description with a current, specific label.

The Neighbor Does Not Display the Description

Descriptions are local administrative text. They are not a forwarding setting or a feature that automatically advertises the label to the neighboring router or switch. Configure documentation separately on each device when required.

Safe and Consistent Description Practices

Identify the connected endpoint whenever possible.
Include the purpose, such as WAN, uplink, management, voice, or server access.
Include a site, provider, circuit reference, VLAN role, or owner when it improves operations.
Use a naming convention consistently across routers and switches.
Keep descriptions accurate after moves, circuit changes, and device replacements.
Do not place passwords, shared secrets, private customer data, or other sensitive information in interface descriptions.

Exam note: The description command is entered in interface configuration mode. It documents an interface but does not enable, disable, route, switch, or secure traffic.

Summary

Configure an interface description by entering privileged EXEC mode, moving to global configuration mode, selecting the intended interface, and issuing description with meaningful text. Verify it with show running-config, replace it by entering a new description, or remove it with no description. Save the running configuration to startup-config when the label must remain after a reboot.