Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

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Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

UDP Lite

Updated: April 10, 2026

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Describes UDP Lite support, its purpose in IPv6 environments for controllers and APs, and important operational impacts and restrictions.

UDP Lite Support is an enhancement to the IPv6 functionality on controllers and APs

  • that enables support for the UDP Lite protocol, and

  • minimizes performance impact by restricting the checksum calculation coverage for the UDP Lite header to 8 bytes rather than requiring a complete payload checksum as standard UDP over IPv6 does.

This feature applies only to the IPv6 addresses of the controller and APs. IPv6 mandates a complete payload checksum for UDP.

Intermediate firewalls must allow UDP Lite protocol (protocol ID 136) packets when using the UDP Lite Support feature. Some firewalls might not provide the option to open specific ports on UDP Lite protocol. In these cases, the administrator must open all ports on UDP Lite.

Feature history

This table provides release and related information about the feature explained in this section.

This feature is also available in all the releases subsequent to the one in which they are introduced in, unless noted otherwise.

Table 1. Feature history for IPv6 CAPWAP UDP Lite support

Feature Name

Release Information

Feature Description

IPv6 CAPWAP UDP Lite support

Cisco IOS XE Cupertino 17.1.1s

From this release, the UDP Lite support feature is an enhancement to the existing IPv6 functionality to support the UDP Lite protocol.

Restrictions for UDP Lite support

  • Mobility IPv6 tunnels do not support the UDP Lite support feature.

Enable UDP lite support (CLI)

Enable UDP Lite, allowing APs to handle IPv6 CAPWAP data packets using commands.

Procedure

1.

Enter the global configuration mode.

Example:

Device# configure terminal
2.

Configure an AP profile and enter the AP profile configuration mode.

Example:

Device(config)# ap profile ap-profile
3.

Enable IPv6 CAPWAP UDP lite on the AP.

Example:

Device(config-ap-profile)# capwap udplite
Note

This message is displayed after the configuration:

This feature is supported only for IPv6 data packets, APs will be rebooted.
4.

Return to the privileged EXEC mode.

Example:

Device(config-ap-profile)# end

Alternatively, you can also press Ctrl-Z to exit global configuration mode.

Verify UDP lite support configuration

To verify the CAPWAP UDP Lite status, use this command:

Device# show ap profile name default-ap-profile detailed
                
CAPWAP UDP-Lite               : ENABLED
Lawful-Interception           : ENABLED
LI timer                    : 60
AWIPS                         : DISABLED
AWIPS Forensic                : Unknown
Client RSSI Statistics
Reporting                   : ENABLED
Reporting Interval          : 30 seconds