Campus lan and Wireless lan solution Design Guide

 
Cisco EWC wireless design model 
Figure 31. 
The Cisco EWC platform provides the following benefits: 
● 
High availability with active and standby controllers running simultaneously on two Cisco Catalyst 9100 
Series APs (configuration synchronization, not HA SSO) 
● 
Software maintenance updates (SMUs) providing hot patching of the controller, AP device packs, and AP 
service packs supported, like standalone controllers 
● 
Cisco DNA Center support for Plug and Play, Automation, and Assurance, including Intelligent Capture 
(similar to other deployment models) 
● 
Advanced RF features such as Flexible Radio Assignment (FRA) and Cisco CleanAir technology (similar to 
other deployment models) 
● 
Automatic configuration of wireless best practices from more than 10 years of experience with large and 
medium-scale implementations 
If the following are true, you should consider deploying the EWC at the site: 
● 
Single site or multisite enterprise locations with up to 100 APs and 2,000 clients per site for Cisco 
Catalyst 9120AX or 9130AX Series running EWC; or up to 50 APs and 1,000 clients per site for Cisco 
Catalyst 9115AX and 9117AX Series running EWC. 
● 
Guest Anchor is not required (currently not supported on the EWC). 
● 
Layer 2 roaming only, without mobility groups. 
Note: 
Cisco 802.11ac Wave 2 APs can join a Cisco EWC network and service clients, but Cisco 802.11ac 
Wave 2 APs cannot run the EWC function. 

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Design Options: Campus Wireless LAN 
AP site tag considerations 
Cisco Catalyst 9800 Series wireless LAN controllers have a multi-process architecture. Multiple wireless 
network controller processes (WNCd) run within a single Cisco Catalyst 9800 platform. The number of WNCd 
instances varies from platform to platform. 
APs (and wireless clients) are load balanced across the WNCd instances for better scale and performance. In 
recent software releases, APs are load balanced across the WNCd instances based upon the site tag applied to 
the AP. If the default site tag is used, APs are load balanced across the WNCd instances in a round robin 
fashion.
Roaming and fast roaming work across site tags. However, 802.11k assisted roaming, 802.11v BSS transition, 
coverage hole detection (CHD), and other proximity based features are managed within individual WNCd 
instances. Therefore, a best practice design recommendation is to configure custom site tags, and not use the 
default site tag. For best performance, use a custom site tag to group APs within a roaming domain. Also, a 
best practice is to limit the maximum number of APs per site tag to 400 APs. 
The following are recommendations based on specific deployments: 
● 
If the deployment has a building with more than 400 APs, consider splitting the building into two parts 
from site tag perspective. Each part should have its own custom site tag with less than 400 APs.