Easy WLC Design Question

[Soporteco]

Hi.

Please advice this deployment:

Customer has two buildings SITE-A and SITE-B. They are connected by a L3 WAN Service Provider. APs in Site A have the WLC-A as primary, and APs in site B have the WLC-B as primary. 

Now the question is:  ( **Since both sites have different Vlans, we always need to use a local DHCP Server)

Can I configure APs in site A as local in WLC-A and configure these same APs as Flexconnect in WLC-B?. If WLC-A fails, APs-A are going to register to WLC-B but they have to use site-A Addresses, meaning they have to use DHCP Server A (Which is Flexconnect feature)

Is it possible to configure one access point as local in one WLC and then register it to another WLC and configure it as Flexconnect? so the AP will work as local in WLC-A, but when WLC-A fails it will work as Flexconnect with WLC-B?

Thanks!

[Rasika Nayanajith · Accepted solution]

Can I configure APs in site A as local in WLC-A and configure these same APs as Flexconnect in WLC-B?. If WLC-A fails, APs-A are going to register to WLC-B but they have to use site-A Addresses, meaning they have to use DHCP Server A (Which is Flexconnect feature)

NO, Not possible,

Once you change the AP mode, that AP can operate in that mode only.If you use "Local mode" in a failure situations client will get IP available from other sites.

If you use "FlexConnect" local switching mode then client will still get the local IPs, in the event of AP failover to secondary WLC.

HTH

Rasika

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[Soporteco]

Thanks a lot.

That means that all APs on both sides have to be in "flexconnect mode" even if they register to the local WLC, right?

[Scott Fella]

Soporteco,

Rasika is right and you would need to have the access point in FlexConnect mode.  There are other ways in which you can design this also.  For example, if site A is your HQ for example and site B is a remote site, you might look at placing both controllers at site A and making the access points in site A as local mode access points and FlexConnect on site B.  This is dependent on your design overall and how many access points are on each site.  I don't like to have may access points in a location using FlexConnect due to the number of access points that you can have in an AP Group and the lack of layer 3 roaming, which can be a design factor (subnet size).  There is also limitation to when you use FlexConnect vs local mode. 

What you also need to consider in your design is that you have one controller in both sites and you might go the FlexConnect route.  If you ever add another controller in each site for redundancy, then will you want to keep it as FlexConnect or not?  If not, then your design will change and you have to look at the impact of the design change. 

-Scott

[Soporteco]

Hi!!

One last question regarding this design:

We're going to configure all APs in Flexconnect mode on both sides. And also configure both controllers in the same mobility group. Nevertheless there are firewalls between the WLCs. What do we have to take into account? Which ports, protocols and IP addresses do we have to permit through these firewalls, in order to deploy this design?

I've read CAPWAP uses UDP 5246/5247 and LWAPP uses UDP 12222/12223. But we need to be certain about all the permissions we need in the FWs.

I would appreciate if someone could help us with this situation.

[Scott Fella]

Those ports are for AP join and depends if your using capwap 5246/5247 or lwapp 12222/12223.  For mobility you need UDP 16666.  Not sure what else you need, but here is a matrix of the ports used:

http://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/113344-cuwn-ppm.html#anc8

-Scott