Embedded Wireless Controller and Standard WLC in the same network

[Taiga2022]

Hey guys, 

I want to know whether I can deploy embedded wireless controller and 2504 controller in the same network?

The APs under each controllers will be operating in different SSID.

Will there be any problems from operation wise if we deployed it?

If there are problems, I would like to get a go around solution also.

Thank you.

Sincerely,

[Flavio Miranda]

Hi

 I can see some problems but 

 For example, the AP when boot up try resolve a specifc URL trying to get the wlc management IP address. On this case, both wlc coud respond to it. 

 Another situation is when AP gets its IP address from dhcp server, you can also pass the wlc management IP address but which one you are going to send?

 You need to separate AP from one wlc in the same vlan and the other wlc in another vlan. 

 If the wlc will propagate different ssids, at least here will be easier. In case you put the same   ssid, different problems will come. 

[Taiga2022]

The WLC is the 2504 which is already EOS.

I will be using Catalyst 9k Series for EWC and new APs.

As far as I checked, since 2504 is not compatible with new 9k series, I don't think the APs will initiate to 2504.

For the IP, I will be using static for APs and EWC as well.

[Flavio Miranda]

But can create a mess in the network. They will send capwap request and will reveive capwap response. They try to join and realize that they cant. Then they will reboot and start over and over. 

 Not simple solution. Yes, you can do it manually but at each weird problem you dont know the reaon, this situaon will pop up as a possible reason. 

[MHM Cisco World]

from my point of view 
since each group of AP will join to specific WLC and use different SSID and there is no roaming then I don't see any issue. 
image that you have two vendor work in same place is same case.

[Taiga2022]

I see. I can propose the solution then. 

Having old devices in the network makes harder for the design wise.

Thank you.

One more question, 

Let's say If I use 2 Autonomous APs, is it possible for me to make them roam the same SSID? 

If so, can I know the configuration advice? 

[JPavonM]

@Taiga2022 for seamless roaming between autonomous APs, no they do not support OKC but is the client who remember the credentials and reauthenticate every time it moves between different autonomous APs.

You can check this post from @Nicolas Darchis (https://community.cisco.com/t5/wireless/pkc-or-okc/m-p/1587847#M183107)

[Nicolas Darchis]

if you are talking about old school IOS APs in autonomous mode (that's really not recent stuff anymore), I would forget about supporting fast roaming (i.e. not renegotiating keys when roaming), but regular roaming (With a reauthentication) will work just fine.

Your 2504/EWC setup can work but it's a source of trouble. When booting the EWC AP, it might be tempted to join the 2504. Even if it can't because the 2504 does not have the software image for it, the AP will still send many join request to it and that will delay that AP becoming the embedded controller. EWC was designed to NOT have any WLC in the subnet. To be honest, I would test it if I were you. You can for sure make it work, but you may encounter issue in case of power failure and all devices rebooting depending on boot order and things like that.

[Taiga2022]

Is there any way to prevent the EWC AP to not send CAPWAP Request to the 2504? 

[Nicolas Darchis]

to prevent it ? no

you could block it with an ACL on the port of the 2504 or the EWC port although.

[Taiga2022]

For the ACL thing,

Could you provide example configuration on GUI or maybe CLI?

and do I also need to add ACLs on newer model APs as well?

[Nicolas Darchis]

no i can't. The ACL to be placed is to be placed onthe switchport of the switch where EWC or 2504 are connected. And blocking CAPWAP ports should be enough. A lot of it depends on your setup/subnets/type of devices you have.

[MHM Cisco World]

friend How AP know the IP of WLC ? 
we will config DHCP to send EWC IP or WLC IP according to AP Op43.
this make EWC AP know the IP of EWC only and send join to it only.

for other AP they will get IP of WLC and only send join to it .

If I am wrong please correct me.

https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/97066-dhcp-option-43-00.html

[Rich R]

If they're on the same vlan they will get the same option 43 from DHCP.

Remember AP behaviour, even when configured with static IP, they will often use DHCP discovery which can cause problems even if you configure static IPs.  They will also use broadcast discovery so will discover both old WLC and new EWC on the same vlan.  They will try to join all the WLC they discover.

The only 100% safe solution is to have them on separate vlans - the docs specifically say NOT SUPPORTED having them on the same vlan.

The solutions Nicholas suggested might help mitigate the problems you create by doing this but you're just making it more complicated and risking introducing other side effects and problems.  Keep it simple and keep them separate.