topic Difficulties with 9800 initial configuration in Wireless

Difficulties with 9800 initial configuration

alee91 — Mon, 06 Nov 2023 18:33:44 GMT

I am new to configuring these 9800 controllers. I have experience with a 5200 series controller and I am aware that the firmware is different. I am in an ongoing battle with DHCP working but not as intended or not working. I am trying to configure the following:

Management VLAN - works as intended

AP Management VLAN - appears to work as intended

SSID1 - Works as intended

SSID2 - allows me to join but gives me an IP address from SSID's VLAN

DHCP Server: External (different subnet than the controller)

Our old controller functions fine and I am aware that I no longer need to utilize interfaces with IPs for the VLANs themselves. I am running into issues when it comes to whether the APs should be setup as Flex or local which then confuses me on the Central Switching, etc.

The APs live on their own VLAN and I have ran through the basic configuration steps as well as the advanced numerous times in an attempt to discover what I may have configured incorrectly. I'm sure that there is a load of information needed but I'm not sure where to start. Any help would be greatly appreciated!

Re: Difficulties with 9800 initial configuration

Mark Elsen — Tue, 07 Nov 2023 07:08:39 GMT

>... in an attempt to discover what I may have configured incorrectly.
- Use the CLI command show tech wireless and feed the output into : Wireless Config Analyzer

Re: Difficulties with 9800 initial configuration

alee91 — Tue, 07 Nov 2023 13:51:55 GMT

I have utilized this numerous times as well as the debug to see what the client issue is to no avail. It talks about DHCP settings which I have followed verbatim with no progress unfortunately.

Does it make sense to use FlexConnect for this or should I be using local? I assumed FlexConnect because the VLAN differs from the multiple VLAN/WLAN IDs that the AP will support. The switchports are configured to access. I've never needed to trunk them before but I'm wondering if the legacy practice needs to be abandoned in order to get this controller to function appropriately.

Re: Difficulties with 9800 initial configuration

Scott Fella — Tue, 07 Nov 2023 15:07:26 GMT

Few things to clarify...
SSID2 - allows me to join but gives me an IP address from SSID's VLAN - What does this mean? What SSID VLAN, from SSID1 or SSID2 or something totally different?

AP Management VLAN - appears to work as intended - This is either working or not. This is something you need to verify and make sure all the ads are on the correct vlan. However, this doesn't affect SSID DHCP.

Re: Difficulties with 9800 initial configuration

Scott Fella — Tue, 07 Nov 2023 15:09:13 GMT

You should also take a look at this convertor to at least give you some idea of what configuration can get carried over and what you will need to figure out.

https://community.cisco.com/t5/wireless/wlc-config-converter-aireos-ios-xe/td-p/2895495

Re: Difficulties with 9800 initial configuration

Mark Elsen — Tue, 07 Nov 2023 15:18:52 GMT

>...I have utilized this numerous times as well as the debug to see what the client issue is to no avail.
- Very strange, WirelessAnalyzer will for sure cover and report fatal errors ,
For 'best DHCP' check : https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9800-series-wireless-controllers/guide-c07-743627.html#DHCPbridgingandDHCPrelay

Flexconnect is used when you have APs at remote offices needing local switching. You will then need a trunk configuration for those APs allowing each WLAN/VLAN , when you only have local APs the switchports can be in access mode and will belong to the vlan used for CAPWAP ,

For client behavior you can use client debug according to : https://logadvisor.cisco.com/logadvisor/wireless/9800/9800ClientConnectivity
You can have client debugs analyzed with : https://cway.cisco.com/tools/WirelessDebugAnalyzer/

When your wireless environment is gradually on track checkout : https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/217738-monitor-catalyst-9800-kpis-key-performa.html#anc5
to observe client health ,

Re: Difficulties with 9800 initial configuration

Rich R — Tue, 07 Nov 2023 15:55:34 GMT

The choice of flexconnect local switching or central switching is nothing to do with old/new - it's all to do with your network design.

For example if your WLC is in a central location but the AP is in a distant office where the client will break out to the internet or office network locally then flexconnect local switching makes sense.

If your existing design is central switching and you wish to keep that unchanged then there's no reason to change it on 9800.

You should not need any DHCP config on the WLC. Simply attach SSID 1 to VLAN A in the wireless profile policy and likewise SSID 2 to VLAN B in wireless profile policy. The handling of client DHCP should be managed by the next hop router or switch on the respective VLANs.