Cisco WLC 5520 with Access Point AP3802 : Configure CAPWAP Path MTU Discovery

Today I am going to talk about the CAPWAP path MTU discovery and in this article I am going to tell you how to configure the CAPWAP Path MTU Discovery.

What is CAPWAP and PMTU and how it works ?

Control and Provisioning of Wireless Access Points (CAPWAP) and Path Maximum Transmission Unit (PMTU). We will talk about how discovery takes place and how it adjusts accordingly when the network changes.

CAPWAP Access Point (AP) is physically installed in a remote office location needing to register to a Wireless LAN Controller (WLC) across the WAN that’s physically installed in a Data Center.

To add further, remote site is logically attached to the Data Center (DC) using VPN or a Generic Routing Encapsulation (GRE) tunnel and your WiFi client fails to authenticate using Extensible Authentication Protocol (EAP-TLS) method and you wonder why. 

With additional overhead introduced by the tunneling protocol, fragmentation can become an hindrance if the network doesn’t adjust accordingly.

Fig 1.1- CAPWAP Tunnel 

In the above mentioned topology, we connected Cisco Access point 3800 which is connected to Cisco Switch 3650 and then to Cisco 3750 and on the other side across the IP network we have the Cisco WLC controller 5520. Let's configure all these devices one by one below.

   Configuration on Cisco Catalyst 3650 Switch 

   

   Configuration on Cisco Catalyst 3750 Switch

   

   Configuration on Cisco Catalyst 3850 Switch

   

   Interface Summary on Wireless LAN Controller 5520   

We will discuss further on new Wireless technology WiFi 6 and the features. Wireless is now the next generation demanding technology as per the research done by various vendors.

Vendors like Cisco, Aerohive, Cambium Networks, Mist, Aruba, Meraki and Mojo is working to make more powerful WiFi 6 Access points and support MIMO with more feature sets.