AP joining process (1.b) -- What is Discovery mechanism - 1?

Hello everyone.

In this post, I will introduce that what discovery mechanism is. Well, this is a long story. It is hard to explain in one post. I will separate it into several different posts. They are

1.b.1 :  basic concept
1.b.2 :  discovery by broadcast
1.b.3:   discovery by Static configuration
1.b.4:   discovery by DHCP and others

OK, Let us go to the basic concept of discovery mechanism. There are two steps in AP->WLC discovery mechanism

/Step 1/
Assign one IP address on AP.

/Step 2/
Find out WLC by using Capwap discovery request and Capwap discover response



// How to assign one IP address on AP//
Basically, there are also two ways, like your PC, one is assigning one static IP.  The other is assigning through DHCP server.


///  Assigning the static IP on AP  ///
You can use the following commands on AP

AP# capwap ap ip address 172.33.68.191 255.255.255.0
AP# capwap ap ip default-gateway 172.33.68.254

You can use the following command to confirm your setting

AP#show capwap ip config                                           
LWAPP Static IP Configuration
IP Address         172.33.68.191    
IP netmask         255.255.255.0    
Default Gateway    172.33.68.254  
Primary Controller 172.33.68.10



/// Assigning IP address from DHCP server ///

** Topology **
AP  ----   SW3750   ----   SWCat6K  ----   WLC5508
                                   
I make dhcp pool on SWCat6k
=====
ip dhcp excluded-address 172.33.67.1 172.33.67.220

ip dhcp pool vlan367
   network 172.33.67.0 255.255.255.0
   default-router 172.33.67.254 
=====

On SW3750, I use interface Gi3/0/4 to connect AP,
=====
interface GigabitEthernet3/0/4
 switchport access vlan 367
 switchport mode access
 spanning-tree portfast
====

And I make packet capture on SWCat6k to see how it work.

As you can see from the picture, DHCP server gives 172.33.67.231to AP in DHCP four-way handshake.
Of course, you can use "show capwap ip config" to check it.



// How to use  Capwap discovery request and response to find out WLC.  //
I will explain that in the next three posts,


See you next time and Good luck !!