If you are geeky, crazy or just curious to try out first generation of Cisco products, new Catalyst 9800 Wireless LAN Controller, this guide might be useful to you 🙂

Jokes aside, C9800 feels like a solid product that is quickly gaining trust of wifi pros and gains traction in the enterprises.

It is a spiritual successor to Cisco AireOS WLCs that sits on the well known IOS-XE that everyone knows and loves :] Thankfully, it has nothing to do with Converged Access, that also was IOS-XE based.

C9800 code was re-written from scratch and offers almost full features parity with its AireOS counterpart.

It’s quite flexible too, meaning you can install it in a private cloud (VMware etc.) public cloud or use it as an on-prem appliance sitting on a switch or a standalone box. All versions offer exact same functionality (with some obvious limitations, like no central data switching when used in public cloud), so you really just need to decide what’s easiest for you to deploy and integrate and think about scale.

I thought that creating an with easy-to-follow ESXi installation steps guide would be a great start!

First of all, here is my lab environment:

And installation steps below:

1. Download the WLC image

• At the time of updating this post Gibraltar-16.11.1c(ED) is the latest TAC recommended version

2. Prepare VMware networking

• C9800-CL requires 3 interfaces – make sure to have all the required VLANs / subnets ready!
  • OOB Mgmt. – not used in Cloud (VM) WLC version, but must be assigned to a vSwitch to bring the interface up
  • Mgmt. – used to manage the WLC and for APs registration. We’re using ESXi 6.0 here, so we have to enable either all 4095 VLANs (trunk) or just one specific VLAN (access). In newer ESXi versions it is possible to allow just selected VLANs on the VMware Distributed Switch trunk. So here we’ll allow all VLANs.
  • HA (L2) – used for HA/SSO and must be configured even when used in a standalone deployment
    • It is important to put C9800 interface that we intend to use as a Redundancy Port L2 HA inter-vWLC link into a seperate, unused VLAN! Note that ‘LAB-VM-L2-HA’ Port Group sits in VLAN 666. Only my two vWLCs’ HA RP ports will be put into that group.

3. Spin the OVA file

• Choose the right size (I used smallest – 1k APs)

4. Map WLC interfaces to VM networking

• WLC Gigabit 1 -> OOB
• WLC Gigabit 2 -> Mgmt.
• WLC Gigabit 3 -> HA between WLC VMs

5. Set correct security parameters on the WLC Trunk interface

• Promiscuous mode must be set to accept, otherwise tagged traffic won’t flow correctly! This step is easy to miss but it’s very important – WLC won’t pass traffic without ticking it 🙂 The C9800 uses multiple MAC address on the same VM, e.g. may be used by the SVI for wireless management (if bridge for centralised clients) or other SVI’s for loopback, etc., all of which will use different MAC address other that the one assigned to the vNIC of the VM.
• Forged Transmits must also be set to accept, as having Forged Transmits set to reject will result in no connectivity due to host verifying the source MAC address which is transmitted by guest OS to match with the MAC address of the VM adapter. As this won’t match for C9800 instance, the ESXi host would drop the packet.

6. Boot the WLC using Virtual Console

The system will install, reboot, check if bootloader upgrade is needed, apply the config (empty at this point), etc. After few minutes, we should be presented with a familiar CLI.

7. Terminate the configuration wizard

• Would you like to enter the initial configuration dialog? [yes/no]: no
• Would you like to terminate autoinstall? [yes]: yes

8. Set a host name

• WLC> en
• WLC# conf t
• WLC(config)# hostname LAB-C9800CL

9. Add login credentials

• LAB-C9800CL(config)# username admin privilege 15 secret <secret>

10. Configure the VLAN for wireless management interface

• LAB-C9800CL(config)# vlan 11
• LAB-C9800CL(config-vlan)# name wireless_management

11. Configure the SVI for wireless management interface

• LAB-C9800CL(config)# interface vlan 11
• LAB-C9800CL(config-if)# ip address 10.10.11.35 255.255.255.0
• LAB-C9800CL(config-if)# no shut

12. Configure management interface

Note: since G1 is OOB, G2 is Mgmt. And G3 is HA in this VM, we’ll first configure G2 to access management plane of the WLC. All SSIDs I’m planning to use will leverage FlexConnect Local Switching (dropping data plane directly onto the switch on the AP level), therefore we don’t need to allow any other VLANs than 11 on this trunk. Still, we might want to test Central Switching, so let’s allow Wireless Users VLAN 20 (configured in later blogs) too:

• LAB-C9800CL(config-if)# interface GigabitEthernet2
• LAB-C9800CL(config-if)# switchport mode trunk
• LAB-C9800CL(config-if)# switchport trunk allowed vlan 11,20
• LAB-C9800CL(config-if)# no shut

Note: depending on your vSwitch configuration, you might need to tag management traffic on the controller side by adding “switchport trunk native vlan 11” command into the config above.

13. Configure a default route (or a more specific route) to reach the device

• LAB-C9800CL(config)# ip route 0.0.0.0 0.0.0.0 10.10.11.1

At this point WLC9800 Mgmt. interface should be pingable 🙂

Note: you might need to shut / no shut int g2 and shut / no shut int vlan 11 for the SVI to come up!

14. Configure country code

Note: wireless network needs to be disabled first. Country code configuration forces GUI to skip the DAY 0 flow as the C9800 needs a country code to be operational. You can enter up to a maximum of 20 countries.

• LAB-C9800CL(config)# ap dot11 5ghz shutdown
  • Disabling the 802.11a network may strand mesh APs.
• Are you sure you want to continue? (y/n)[y]: y
• LAB-C9800CL(config)# ap dot11 24ghz shutdown
  • Disabling the 802.11b network may strand mesh APs.
• Are you sure you want to continue? (y/n)[y]: y
• LAB-C9800CL(config)# ap country GB
  • Changing country code could reset channel and RRM grouping configuration. If running in RRM One-Time mode, reassign channels after this command. Check customized APs for valid channel values after this command.
• Are you sure you want to continue? (y/n)[y]: y

Don’t forget to re-enable the radios 🙂

• LAB-C9800CL(config)# no ap dot11 5ghz shutdown
• LAB-C9800CL(config)# no ap dot11 24ghz shutdown

Finally, validate all is up and happy:

• LAB-C9800CL# show ap dot11 5ghz summary
• LAB-C9800CL# show ap dot11 24ghz summary

15. Create a certificate for the AP to join the virtual controller

Note: you must specify the interface for the wireless management, create certificate and verify certificate installation. If you skip the certificate/trustpoint configuration, APs will not be able to join. However, you can go to the GUI and configure it by importing the desired certificate.

• LAB-C9800CL(config)# wireless management interface vlan 11
• LAB-C9800CL(config)# exit
• LAB-C9800CL# wireless config vwlc-ssc key-size 2048 signature-algo sha256 password 0 <pwd>
• LAB-C9800CL# show wireless management trustpoint

At this point, it should be possible to access the WLC via GUI using HTTPS, IP set in step 9 and credentials set in step 7!

SSH will not work yet as the lines are not yet configured.

Credentials have already been set, so we can jump straight into the stuff that’s needed to make SSH work!

Domain name is needed for RSA key generation process.

We’ll also need to specify enable password to allow us to use privileged mode.

16. Configure access via SSH

• LAB-C9800CL(config)# enable secret <secret>
• LAB-C9800CL(config)# aaa new-model
• LAB-C9800CL(config)# ip domain-name <domain-name>
• LAB-C9800CL(config)# crypto key generate rsa general-keys modulus 1024
• LAB-C9800CL(config)# line vty 0 530
• LAB-C9800CL(config-line)# privilege level 15
• LAB-C9800CL(config-line)# transport input ssh

Voilà! We are now ready to register our first AP to the new, shiny and sexy WLC 😀 Well done!