topic Re: WLC Catalyst 9800L HA question in Wireless

WLC Catalyst 9800L HA question

jjtech — Sun, 03 Dec 2023 08:41:32 GMT

Hi,

I am replacing an old WLC with 2 new Cisco Catalyst 9800L Wireless Lan Controllers with HA.

I have 2 questions please that I need your experts input on:

Before doing the HA redundancy configuration (RP+RMI), what configuration specific to the standby WLC should I do on it only? Hostname, Management IP, SSH access, needed VLANs? Will everything else be taken from from the Active WLC?
What should be done from the access points perspective to make sure they will actually use the backup WLC in case of failure? I will be using option 43 on the DHCP server to make sure the APs know where to register. Should I specify only the wireless management interface IP address of the Active WLC in option 43 ? Will this IP be assumed by the backup WLC in case of failure?

I know these may be basic questions, however I am new to the High Availability setup with Cisco WLC, and I couldn't find the needed details in the Cisco documentation.

Thanks,

Re: WLC Catalyst 9800L HA question

MHM Cisco World — Sun, 03 Dec 2023 08:52:02 GMT

Before doing the HA redundancy configuration (RP+RMI), what configuration specific to the standby WLC should I do on it only? Hostname, Management IP, SSH access, needed VLANs? Will everything else be taken from from the Active WLC? Yes correct' only these config need other config is done in active later and bulk sync to standy
What should be done from the access points perspective to make sure they will actually use the backup WLC in case of failure? I will be using option 43 on the DHCP server to make sure the APs know where to register. Should I specify only the wireless management interface IP address of the Active WLC in option 43 ? Will this IP be assumed by the backup WLC in case of failure? No need anything from AP' the AP see only one wlc IP and use it' when active failed this IP is move from active (old) to standby (new active).

MHM

Re: WLC Catalyst 9800L HA question

balaji.bandi — Sun, 03 Dec 2023 09:36:08 GMT

Most of the configuration required on Main WLC only, Standby need only basic config, so most configuration sync from Primary

have you checked below :

https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/213915-configure-catalyst-9800-wireless-control.html

Re: WLC Catalyst 9800L HA question

jjtech — Sun, 03 Dec 2023 12:26:09 GMT

Thank you for the reply.

So for option 43 I use the IP address of the wireless management interface on the Active WLC ? I mean there are no dedicated separate virtual IP (similarly to the virtual IP used in the HSRP concept for example) ?

Re: WLC Catalyst 9800L HA question

jjtech — Sun, 03 Dec 2023 12:24:51 GMT

Thank you Balaji, the article is helpful, but they didn't give much details about the access point side of the configuration.

Re: WLC Catalyst 9800L HA question

MHM Cisco World — Sun, 03 Dec 2023 12:37:12 GMT

No op43 will be only IP of active wlc.

wlc HA dont like hsrp which use VIP of hsrp group as GW in dhcp.

MHM

Re: WLC Catalyst 9800L HA question

balaji.bandi — Sun, 03 Dec 2023 12:48:20 GMT

You mean access point onboarding : Cisco have each section that is for HA setup.,

there are many documents available - how you can join the AP to WLC and deploy other parameters :

example guide below :

https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-4/deployment-guide/c9800-webui-dg.pdf

good blog :

https://mrncciew.com/category/ap-registration/

Re: WLC Catalyst 9800L HA question

Mark Elsen — Sun, 03 Dec 2023 13:11:33 GMT

- FYI : https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/213915-configure-catalyst-9800-wireless-control.html
For further consistency checks after intended configuration is finished use CLI command show tech wireless (on the primary) and feed the output into : Wireless Config Analyzer

Re: WLC Catalyst 9800L HA question

Mark Elsen — Sun, 03 Dec 2023 13:13:16 GMT

>....What should be done from the access points perspective to make sure they will actually use the backup WLC in case of failure?
Nothing , once the HA is operational , all of that is automatic

Re: WLC Catalyst 9800L HA question

Rich R — Sun, 03 Dec 2023 23:02:49 GMT

It operates like a switch stack or cluster - so the HA-SSO pair only has the one single name and IP address which you use.

Re: WLC Catalyst 9800L HA question

Rich R — Sun, 03 Dec 2023 23:03:36 GMT

From the access point point-of-view it looks like a single WLC.

Re: WLC Catalyst 9800L HA question

Ambuj M — Sun, 03 Dec 2023 23:39:02 GMT

Correct.