Release Notes for Cisco Catalyst 9800 Series Wireless Controller (17.9.4a)

Overview of Cisco IOS XE 17.9.4a

The Cisco Catalyst 9800 Series Wireless Controller software version 17.9.4a serves as the base code for deploying specific Software Maintenance Updates (SMU) and AP Service Packs (APSP). Maintaining the correct base version is critical for system stability and the successful application of patches.

Understanding Patch Types

Cisco provides two primary methods for addressing software issues on the Catalyst 9800 platform:

• APSP (AP Service Pack): Designed to resolve issues specific to Access Points. Installing an APSP does not require a controller reload. Once the update is applied, Access Points will automatically update their images and perform a staggered reboot to minimize network disruption.
• SMU (Software Maintenance Update): These are patches for the Wireless Controller itself. They are categorized into COLD/RELOAD SMUs, which require a controller reboot, and HOT/HITLESS SMUs, which provide seamless patching without requiring a reload.

Installation and Maintenance

Before installing any patch, verify that the APSP or SMU is compatible with your specific hardware model. APSPs may be targeted at specific AP models or applicable to all COS-based Access Points. Always consult the official deployment guides for detailed installation procedures to ensure network integrity.

Important Considerations and Disclaimer

The SMUs and APSPs provided for this release are classified as Temporary Software Modules. While they have undergone testing and are suitable for production environments to mitigate specific software issues, they are intended as interim solutions. Customers are strongly encouraged to migrate to the next official Maintenance Release (CCO release) once it becomes available, as these future releases will have the fixes permanently integrated. This software is fully supported by the Cisco Technical Assistance Center (TAC).

Resolved Caveats

This release addresses several critical issues, including kernel panics, connectivity problems, and hardware-specific errors. Notable fixes include:

• Resolution of kernel crashes and panic states on various AP models including the 9105, 9120, 9130, and 1815 series.
• Fixes for bad block monitoring on C9105AXW units.
• Correction of temperature reading errors on 9136I-ROW Access Points.
• Resolution of EAP-TLS packet processing issues on 2800 series flex APs.
• Fixes for unexpected disjoins from the controller and DTLS establishment failures.
• Correction of QoS data frame transmission issues related to radar detection flags.