Campus lan and Wireless lan solution Design Guide

Cisco FlexConnect design model 
Cisco FlexConnect is a wireless solution primarily for deployments that consist of multiple small remote sites 
(branches) connected into a central site. Cisco FlexConnect provides a highly cost-effective solution, enabling 
organizations to configure and control remote-site APs from the headquarters through the WAN, without 
deploying a controller in each remote site.
Cisco APs operating in Cisco FlexConnect mode can switch client data traffic out their local wired interface and 
can use 802.1Q trunks in order to segment multiple WLANs. The trunk's native VLAN is used for all CAPWAP 
communication between the AP and the controller. This mode of operation is referred to as Cisco FlexConnect 
local switching and is the mode of operation described in this guide.
 
Cisco FlexConnect design model 
Figure 29. 
Cisco FlexConnect can also tunnel traffic back to the centralized controller, which can be used for wireless 
guest access. You can use a shared controller pair or a dedicated controller pair in order to deploy Cisco 
FlexConnect.
In a shared controller model, both local-mode and Cisco FlexConnect configured APs share a common 
controller. A shared controller architecture requires that the WLAN controller support both Cisco FlexConnect 
local switching and local mode. In this guide, the WLAN controllers that support both are the Cisco Catalyst 
9800-80, 9800-40, 9800-L Series appliances and the Cisco Catalyst 9800-CL for private cloud wireless 
controllers.
You may be able to use a shared deployment if you meet all the following requirements: 

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● 
You have an existing local-mode controller pair at the same site as your WAN aggregation. 
● 
The controller pair has enough additional capacity to support the Cisco FlexConnect APs. 
● 
The number of site tags with Cisco FlexConnect profiles required matches the capabilities of the 
controller pair. 
If you don't meet the requirements for a shared controller, you can deploy dedicated Cisco Catalyst 9800-80, 
9800-40, or 9800-L Series wireless controllers. The Cisco Catalyst 9800-CL virtual form factor, deployed in 
either a private cloud or public cloud is an alternative to an appliance, since wireless traffic is typically locally 
terminated in a Cisco FlexConnect deployment. The Cisco Catalyst 9800-CL deployed within a public cloud only 
supports Cisco FlexConnect with local termination. The Cisco Catalyst 9800-CL deployed within a private cloud 
supports local termination as well as centralized termination of wireless traffic, although at lower scale (up to 1.5 
Gbps) than a dedicated controller appliance.
For highest resiliency, deploy a pair of controllers in HA SSO configuration. Alternatively, you can deploy N+1 
high availability in order to provide cross-site resiliency if desired. With N+1 HA, APs are configured with a 
primary, secondary, and even a tertiary WLC, as desired. If connectivity to the primary WLC fails (the CAPWAP 
tunnel goes down), the AP establishes connectivity to the secondary WLC – potentially deployed at a different 
regional geographic location. 
If all of the following are true at a site, you should consider deploying Cisco FlexConnect at the site:
● 
The site LAN is a single access-layer switch or switch stack. 
● 
The site has fewer than 50 APs. 
● 
The site is one of many small remote sites connected to a central location 
● 
The site has a WAN latency less than 100ms round-trip to the shared controller.