Cisco WLC 3500 HA between Data Center

[lmanavalan]

Hi,

I have Two Cisco WLC 3500 installed at 2 different DC.

I need to configure Redundancy between the two WLC. Since the WLC are installed at 2 different DC the management IP of the two wlc are in different subnet.

Whats is best possible Redundancy mode i can use (SSO will be problem to span the vlan and RP port Accross DC).

How can i get redundancy between 2 WLC with management on different subnet.

Regards

Logesh

[Scott Fella]

You can’t. SSO requires that the management and RP is on the same subnet. Your design should be N+1. SSO will not work if your AP’s are in local mode as the dynamic interfaces also have to be on the same subnet.

[Leo Laohoo]

---

@lmanavalan wrote:

Since the WLC are installed at 2 different DC the management IP of the two wlc are in different subnet.

---

Best practice is to put the management IP address in the same subnet.  

What is the link between the two sites?  Is it dark fibre or an ISP link?

[lmanavalan]

Hi
The link between the DC is Dark Fibre and management IP range of both DC are different subnet range.
This WLC is the controller to all the AP installed at the HO. HO is connected to the 2 DC via a layer 3 link.
Thanks
Logesh

[lmanavalan]

Hi

How about configuring the 2 wlc as separate controllers. Under the all AP configure Primary and secondary controller on the AP preference.

Thanks

Regards

Logesh

[Leo Laohoo]

That can be done but this method is slower to HA SSO.

[patoberli]

This is what is called N+1 redundancy. It works, but the hand-over if the primary controller fails is slower. You also have to configure both controllers independently and always keep the same software release installed on both of them.

[Scott Fella]

That is how you should design it in your case. Just define the primary and secondary WLC in the AP’s high availability.

[lmanavalan]

Hi

Planning to use this Option.

And also since the APs are in HO (at different location) thinking of converting the APs from Local to Flexiconnect. The APs will get the IP from Local DHCP on the connetedcisco switch. Since the OSPF is configured so i believe AP can talk to WLC and form CAPLAP tunnel to communicate to the WLC.

Thanks

Logesh

[Scott Fella]

Just make sure you plan right. There is a limitation on how many AP’s in a FlexConnect Group (100). Also make note of features that are not available in FlexConnect mode vs local. Doesn’t affect many FlexConnect deployments but just make sure.

[lmanavalan]

Hi

Thanks for the reply.

Configuring the WLC and AP(Flexconnect) in different subnet and connecting then throgh the Layer 3 rotuing shouldn't be a problem right.

The reason why i want to get the WLC Redunduncy, AP mode and AP & WLC connecting correct is in furture their will be another wlc (managed by 3rd party) be installed and i might need to get the mobility group & anchor between the current one and future one. I want to get the base design right so i can make sure this design can be scalabe as required in furture rather than rebuiling it.

Regards

Logesh

[Scott Fella]

FlexConnect doesn’t support L3 roaming and that is why the AP’s should be in the same subnet and same FlexConnect Group. This was you have roaming supported. If you have more than 100 AP’s, then stop at an area or adjacent floor where you might not care much about roaming.