topic Re: WLC 9800-CL - help with correct interface/SVI configuration in Wireless

WLC 9800-CL - help with correct interface/SVI configuration

fabioairoldi — Fri, 26 Apr 2024 06:38:55 GMT

Hello all,

we are currently transitioning to a virtual 9800-CL WLC, hosted on a VMWare node on premise. The WLC and the FlexConnect APs are working correctly but I am experiencing a weird behavior with the interfaces.

The APs are on VLAN 1 - 192.168.2.x/24

The WLC has only the eth #2 connected

right now it's a trunk with VLAN 1 (native) and 30

on the ESXI side, the WLC is connected to a vSwitch on a trunk port

and the physical adapter vmnic2 is connected to a cisco switch on a trunk (native 1) port.

Now, from my perspective, the VLAN 30 is completely superfluous. I reach the WLC with the 192.168.2.95 IP, the APs connect through 192.168.2.95, etc...

so I was going to delete VLAN 30 from the config. However, as soon as I disable the VLAN 30, I lose connectivity to the WLC, even from the 192.168.2.95 interface. I have to log in from the esxi console and re-enable it.

What am I missing here? Could it be something simple like VLAN 1 being tagged on some trunks and not some others (I think everything is right, but I could check further), or is there a deeper reason for a second IP?

thank in advance

Re: WLC 9800-CL - help with correct interface/SVI configuration

Mark Elsen — Fri, 26 Apr 2024 08:34:38 GMT

- Not sure if the overall networking topology is supported = have a checkup of the WLC 9800-CL configuration with the CLI command show tech wireless and feed the output to : Wireless Config Analyzer

Re: WLC 9800-CL - help with correct interface/SVI configuration

fabioairoldi — Fri, 26 Apr 2024 09:32:47 GMT

Thank you, the Analyzer tool is helpful, however it's not that the current config has issues, it's that I am experiencing an unexplicable (for me) behaviour when changing it. I was hoping for some tips in analyzing the overall network topology I showed in the original post to see if there's issues.

Re: WLC 9800-CL - help with correct interface/SVI configuration

Mark Elsen — Fri, 26 Apr 2024 09:47:44 GMT

- Make sure that WirelessAnalyzer does not report any red flags on the overall wlc-checkresults , because if there are , these for sure must be corrected

- I noticed The WLC has only the eth #2 connected
Normally this is not how it is done , even for the virtual controller , 3 effective interfaces are needed , SP , WMI and redundancy port being connected through the hypervisor VM settings ,

Re: WLC 9800-CL - help with correct interface/SVI configuration

fabioairoldi — Fri, 26 Apr 2024 10:09:45 GMT

and the 3 effective interfaces should be 3 different ports, they can't be 3 VLANs on the same trunk port?

Re: WLC 9800-CL - help with correct interface/SVI configuration

Mark Elsen — Fri, 26 Apr 2024 10:20:02 GMT

- Correct , because even the 9800-CL , expects these 3 to be available (unless for remote cloud deployments but then the overall starting deployment is different too)

Re: WLC 9800-CL - help with correct interface/SVI configuration

Rich R — Fri, 26 Apr 2024 14:14:54 GMT

Check that you followed every single step of the 9800-CL VMWare deployment guide very carefully - go through it again step by step.

Also refer to https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/technical-reference/c9800-best-practices.html#C9800CLconsiderations without those settings it will not work.

Your screenshot doesn't show any of the WLC port VLAN config on the ESX - only the top level which is labelled VLAN ID: 4095!

It's a general rule in networking (with very few exceptions) that you should never use VLAN 1 - think about using a non-default VLAN for your setup.

Re: WLC 9800-CL - help with correct interface/SVI configuration

fabioairoldi — Fri, 03 May 2024 07:43:09 GMT

I am aware VLAN 1 shouldn't be used, but this is a situation where you inherit a massive infrastructure with legacy flaws and have to work around it. Changing the management VLAN for every networking device sounds like a nightmare I am not ready to face honestly.

What kind of further information is needed? I am sifting through the config guides and best practices but so far I can't see where I went wrong.

Re: WLC 9800-CL - help with correct interface/SVI configuration

Rich R — Fri, 03 May 2024 08:24:29 GMT

I mentioned VLAN 1 as advice in the last paragraph - not a solution to the problem - although it sometimes can be related to the problem. Did you see what I said above that?

Re: WLC 9800-CL - help with correct interface/SVI configuration

fabioairoldi — Fri, 03 May 2024 09:23:58 GMT

Yeah, absolutely, I am currently reviewing the various setup steps in the guide and best practices - I also feel that some steps would be easier if I wasn't forced to use default VLAN 1, that's why I posted that.

I'll get back to the thread if there's something I can't wrap my head around in the config, thanks for now!

Re: WLC 9800-CL - help with correct interface/SVI configuration

Mark Elsen — Fri, 03 May 2024 09:29:12 GMT

>...if I wasn't forced to use default VLAN 1, that's why I posted that.
- That shouldn't be needed at all , get the VLAN which you want and keep using WirelessAnalyzer with the CLI command show tech wireless and feed the output to : Wireless Config Analyzer

For all configurating attempts = just go for it = This is so good