How to Read Cisco Wireless Controller Specifications
Start with the specifications that decide which controller fits: how many access points and clients it manages, by default and with a license, its throughput, and the Wi-Fi 6, 6E and 7 access points it runs. Then check uplinks, high availability, power and licensing.
01
Access Point and Client Capacity
The number of access points and clients one controller manages. The C9800-L-C-K9 and C9800-L-F-K9 manage 250 access points and 5,000 clients, or 500 and 10,000 with the perpetual LIC-C9800L-PERF Performance license. Every other model has one fixed limit, from 500 access points on the CW9800L to 6,000 on the C9800-80-K9, CW9800H1 and CW9800H2.
When comparing modelsSize for the access point and client count after growth at about 80% of the maximum, and size one unit of a high-availability pair, not both. Beyond 250 access points, price a Performance license for both units of a C9800-L-C-K9 or C9800-L-F-K9 pair against a CW9800L pair, which needs none.
02
Throughput (Controller Performance)
Maximum throughput is the highest traffic rate Cisco publishes for a controller, from 5 Gbps on the C9800-L-C-K9 and C9800-L-F-K9 to 100 Gbps on the CW9800H1 and CW9800H2. With the Performance license, the C9800-L-C-K9 and C9800-L-F-K9 reach 10 Gbps, measured with 1374-byte packets.
When comparing modelsCompare it with the client traffic that passes through the controller, not with access point link rates. With IMIX traffic the C9800-L-C-K9 and C9800-L-F-K9 stay at 5 Gbps even with the license, so buy the Performance license for access point and client scale, not for throughput.
03
Wi-Fi 6, 6E and 7 Support
A controller has no radios: the access points it manages set the Wi-Fi standard and the 2.4, 5 and 6 GHz bands. All eight controllers here run Wi-Fi 5 Wave 2, Wi-Fi 6/6E and Wi-Fi 7 access points. 6 GHz access points need Cisco IOS XE 17.7.1 or later, and Wi-Fi 7 access points 17.15.2.
When comparing modelsWhen comparing models, check the release, not only the model: every model here supports Wi-Fi 7 access points from Cisco IOS XE 17.15.2, and the CW9800L from its first release, 17.18.2. Each access point model has its own minimum release.
04
Wi-Fi 7 Channels and Security
Wi-Fi 7 access points add Multi-Link Operation, which turns on with 802.11be, and 320 MHz channels, which exist only in the 6 GHz band. Dynamic channel assignment stops at 160 MHz by default, so 320 MHz is enabled in the 6 GHz RF profile.
When comparing modelsPlan Wi-Fi 7 WLANs with WPA3: from Cisco IOS XE 17.15.3, a WLAN that does not meet the Wi-Fi 7 requirements runs as 802.11ax. Cisco documents no difference between these controllers for channel width, DFS or band selection, so these features do not decide the model.
05
Uplink Ports and Optics
Uplink ports connect the controller to the switch and carry traffic between access points and the controller, client traffic and in-band management. The port type decides which optics or cables fit and must be budgeted.
When comparing modelsMatch port speed and type to the switch. The CW9800M and CW9800H1 add 25G SFP28 ports and the CW9800H2 40G QSFP ports. The CW9800L has two 1/10G SFP+ ports and no RJ-45 data ports; the C9800-L-C-K9 is the copper option, with two 1/2.5/5/10G RJ-45 ports.
06
High Availability
Stateful switchover (SSO) runs two controllers as one active-standby pair with configuration and access point and client state in sync, so clients do not reconnect after a failure. N+1 redundancy instead has access points join a secondary controller when the primary is unreachable.
When comparing modelsBuild an SSO pair from two units of the same Product ID and software release; Cisco does not pair a C9800-L-C-K9 with a C9800-L-F-K9. The redundancy port takes 1/10G SFP optics on the CW9800M, CW9800H1 and CW9800H2, and 1G SFP optics on the C9800-40-K9 and C9800-80-K9.
07
Power Supplies and Rack Space
The C9800-L-C-K9, C9800-L-F-K9 and CW9800L are half-width one-rack-unit controllers powered by a 110 W external adapter. The C9800-40-K9, CW9800M, CW9800H1 and CW9800H2 take one rack unit with power supply modules, and the C9800-80-K9 takes two.
When comparing modelsCheck what ships in the box. The C9800-80-K9, CW9800H1 and CW9800H2 ship with two AC or DC supplies; the C9800-40-K9 and CW9800M ship with one AC supply, so order a second for redundancy. The CW9800L adds redundancy only with the CW9800L-RPS= kit, and the C9800-L-C-K9 and C9800-L-F-K9 have none.
08
Licensing
No license is needed to boot a Catalyst 9800 or CW9800 controller, but each access point that joins needs a Cisco DNA or Cisco Networking subscription.
When comparing modelsBudget access point subscriptions separately from the controller. The Performance license for the C9800-L-C-K9 and C9800-L-F-K9 is a separate perpetual license that only raises their scale, and both units of a high-availability pair need it.
