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

Data Datagram Transport Layer Security

Updated: April 10, 2026

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Introduces 802.1X authentication, outlining its security functions, supported EAP methods, integration with Cisco devices, feature history, and requirements for AP credential provisioning and authentication processes on Wave 2 and Wi-Fi 6 APs.

A data Datagram Transport Layer Security (DTLS) is a security protocol that

  • encrypts CAPWAP data packets sent between an access point and a controller

  • uses separate UDP ports for control (5246) and data (5247) packets,

  • is a standards-track IETF protocol that can encrypt both control and data packets based on TLS, and

  • supports v1.2 as the latest version available.

Feature history for data DTLS

Feature name

Release information

Feature description

Data Datagram Transport Layer Security

Cisco IOS XE Gibraltar 16.7.1

The data Datagram Transport Layer Security (DTLS) is a standards-track IETF protocol that can encrypt both control and data packets based on TLS.

CAPWAP control and data packets

CAPWAP control packets are management packets that are exchanged between a controller and an AP. CAPWAP data packets encapsulate forwarded wireless frames.

If an AP does not support DTLS data encryption, DTLS is enabled only for the control plane, and a DTLS session for the data plane is not established.

DTLS handshake

If an AP supports Data DTLS

  • It enables data DTLS after receiving the new configuration from the controller

  • The AP performs a DTLS handshake on port 5247 and after successfully establishing the DTLS session, and

  • All the data traffic (from the access point to the controller and the controller to the access point) is encrypted.

Note

The throughput is affected for some APs that have data encryption enabled.

The controller does not perform a DTLS handshake immediately after processing client-hello with a cookie, if the following incorrect settings are configured:

  • ECDHE-ECDSA cipher in ap dtls-cipher and RSA-based certificate in “wireless management trustpoint”.

  • RSA cipher in ap dtls-cipher and EC-based certificate in “wireless management trustpoint”.

This is applicable when you move from CC > FIPS > non-FIPS mode.

Note

If the DHCP lease time of the AP is less and the DHCP pool is small, the AP join may fail or a failure in establishing the Data Datagram Transport Layer Security (DTLS) session may occur. In such scenarios, associate the AP with a named site-tag and increase the DHCP lease time for at least eight days.

Configure data DTLS (GUI)

Complete this task to enable DTLS data encryption for the APs on the controller.

Procedure

1.

Click Configuration > Tags and Profile > AP Join.
2.

Click Add to create a new AP Join Profile or click an existing profile to edit it.
3.

Click CAPWAP > Advanced.
4.

Check Enable Data Encryption check box to enable Datagram Transport Layer Security (DTLS) data encryption.

5.

Click Update & Apply to Device.

The DTLS data encryption for the APs on the controller is enabled.

Configure data DTLS (CLI)

Complete this task to enable DTLS data encryption for the access points on the controller.

Procedure

1.

Enter the global configuration mode.

Example:

Device# configure terminal
2.

Configure an AP profile and enter AP profile configuration mode.

Example:

Device(config)# ap profile ap-profile-name
Note

Use the default AP profile (default-ap-profile) or create a named AP profile, as shown in the example.
3.

Enable link encryption on your profile.

Example:

Device(config-ap-profile)# link-encryption

Answer Yes, when the system prompts you with this message: 

Enabling link-encryption will reboot the APs with link-encryption.
                        Are you sure you want to continue? (y/n)[y]:
Note

If you set stats-timer as zero (0) under the AP profile, then the AP will not send the link encryption statistics.
4.

Return to privileged EXEC mode.end

Example:

Device(config-ap-profile)# end
5.

(Optional) Display the DTLS session established for the AP that has joined this controller.

Example:

Device# show wireless dtls connections
6.

(Optional) Display the link encryption-related statistics (whether link encryption is enabled or disabled) counter received from the AP.

Example:

Device# show ap link-encryption

The DTLS data encryption for the access points on the controller is now enabled.

Device# configure terminal
Device(config)# ap profile ap-profile-name
Device(config-ap-profile)# link-encryption
Device(config-ap-profile)# end
Device# show wireless dtls connections
Device# show ap link-encryption