What is the fastest & easiest way to configure multiple dynamic interfaces on a WLC. If you need to do it via GUI you need to go to Controllers > Interfaces section & define it. See below two screenshots.

Now we will see how we could achieve this using CLI. To make it easy think about how you create an interface (SVI) on a layer 3 switch for a DHCP clients subnet.We all configure it like this without much trouble.

vlan 80
name data1
!
interface Vlan80
 ip address 10.10.80.2 255.255.255.0
 ip helper-address 10.100.1.2

You can apply the same logic when defining interfaces on WLC. Remember these logical steps

1. Create an dynamic interface
2. Assign a corresponding vlan number to interface.
3. configure IP address, subnet mask & gateway
4. Specify the DHCP address (primary/secondary)
5. Assign a physical port (or Port channel if LAG is enabled)

Here is the corresponding CLI commands to do this on a WLC. If you want to define another dynamic interface you can simply copy this with IP/vlan changes.

config interface create data1 80 <-- data1 is the interface name
config interface vlan data1 80
config interface address dynamic-interface data1 10.10.80.10 255.255.255.0 10.10.80.2  
config interface dhcp dynamic-interface data1 primary 10.100.1.2 
config interface port data1 1 <-- WLC port 1 is connected to Switch
!
config interface create data2 90
config interface vlan data2 90
config interface address dynamic-interface data2 10.10.90.10 255.255.255.0 10.10.90.2  
config interface dhcp dynamic-interface data2 primary 10.100.1.2 
config interface port data2 1

If you ask to create 3 dynamic interfaces in each controller (3 or 4) it should not take more than 2-3 min via CLI. Can you do the same via GUI in a such short time frame ? I doubt  . Therefore get used to CLI for this sort of repetitive tasks in the exam to save your valuable time.

Now we will look at how to handle if they ask to do it with interface groups. They may not ask directly to configure interface groups, but if you see same SSID map to more than one dynamic interface/vlans or talk about VLAN Select feature you should know you have to create interface group to fulfill this task.

For this, first you have to create an interface group & then assign required dynamic interfaces to interface group. I will create an interface group called “data-int-group” & assign data1 & data2 dynamic interfaces to that. In GUI, you can do that under Controllers > Interface Group section. (see below two screenshots)

In CLI, you can do that by using following 3 lines.

config interface group create data-int-group "Int Group for Data Subnets"
config interface group interface add data-intgroup data1
config interface group interface add data-intgroup data2

Finally we will look at how we can map these interfaces or interface group to a WLAN. Again logic here is to define a WLAN first & then map an interface or interface group into WLAN. I have shown “data1” & “data-int-group” in the same screenshot below, but you can select only one of these in drop-down box menu. For the simplicity I have only enabled “Broadcast SSID” feature. Once you familiar with other advanced features of WLAN you can include them in to this CLI command set before enabling the WLAN.

In CLI you can achieve this with following 4 CLI commands. In this example I have defined two  basic WLANs (ID 4 & 5)  & map into two dynamic interfaces
(data1 & data2) created with SSID broadcast feature. If you want to map into interface group, you can type interface group name instead of interface name.

config wlan create 4 data1 data1  <- SSID & profile name data1
config wlan interface 4 data1
config wlan broadcast-ssid enable 4
config wlan enable 4
!
config wlan create 5 data2 data2  
config wlan interface 5 data2
config wlan broadcast-ssid enable 5
config wlan enable 5

Keep in mind there can be further complexities (AP groups, WLAN ID > 16, etc). My preference is do this basic repetitive tasks via CLI to save time & do more complex task (non-repetitive) via GUI.

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