Cisco C9800-40-K9 Catalyst 9800-40 Fixed Wireless Controller

C9800-40-K9 Fixed-Interface Deployment Profile

C9800-40-K9 is the one-rack-unit Catalyst 9800-40 physical wireless controller for midsize and large deployments. Cisco publishes a maximum of 2,000 access points, 32,000 clients and 40 Gbps throughput. Four front-panel data ports operate at 10G or 1G; there is no 9800-80 modular uplink bay on this PID.

Fixed uplink design

Map client traffic, CAPWAP, in-band management and northbound connectivity across the four supported SFP+/SFP interfaces. Validate the exact Cisco optics and link mode, because 10/100-Mbps operation is not supported on those ports. Keep the separate management and redundancy links out of the production-throughput calculation.

Power and physical installation

The 9800-40 uses AC power and supports an optional redundant hot-swappable AC supply. Cisco specifies a 1RU form factor and maximum power consumption of 381W. The installation record should include rack depth, power-feed diversity, spare-supply status, console access and both redundancy-port media choices.

2,000-AP failure-domain gate

Size the design from real AP inventory, client concurrency, FlexConnect sites, RF/policy tags and traffic rather than using the platform maximum as a target. For 1:1 SSO or N+1 operation, test stateful failover, AP rejoin, client continuity and aggregate traffic with one controller unavailable. A proposal requiring 9800-80 scale or modular high-speed uplinks is not an equivalent 9800-40 deployment.

Subscription and migration record

Each AP joining a Catalyst 9800 requires the appropriate Cisco DNA subscription. Cisco's lifecycle notice names CW9800M as the replacement product for C9800-40-K9, with end of sale on December 31, 2025 and last support on December 31, 2030. Preserve IOS XE compatibility, Smart Account ownership and AP-license evidence, then compare the successor's interfaces and supported release before migration.

Official sources: Cisco Catalyst 9800-40 data sheet and Cisco C9800 lifecycle and migration notice.