5508 to 5760 w/3850. Migrating from CUWN to Converged access.

Question

Hi!
I have a 5508 WLC managing APs in local and flexconnect mode in the current environment. 
There's a plan to migrate to converged access using 5760 WLC w/HA as MC, 3850 as MA and keep the 5508 as N+1 controller enabling new mobility. 
It will look like this:
1 MC 5760 w/HA
10 3850 as MA
1 5508 as N+1 (managing flexconnect APs and backup if the 5760 pair fails)
The questions I have:
1. After enabling new mobility in the 5508.
Will I still be able to use flexconnect mode for the remote locations? I know the 5760 doesn't support flexconnect mode, but I'm not sure if the flexconnect feature is not supported in a converged access deployment.
2. Will I be able to manage and configure everything in the 5760 (MC) and the WLC will push the configurations, WLANS, settings, etc to the 3850s (MA)? Or do I also need to configure WLANS, etc on each individual 3850?
3. Current license count in the 5508 is at 350 APs.
The new deployment will have 10 3850s with 5 AP licenses per switch and the 5760 will come with 25 AP licenses. That's a total 75 AP licenses. 
I would need to purchase 225 additional licenses on the 5760 to make a total of 350 AP licenses.
Will I be able to move the switches' AP licenses to the 5760 to make 350 AP licenses? 
The plan is to keep the 5508 as a staging controller to move the APs in the event of a FW upgrade in the 5760.

Answer 1

First of all 5760 & 5508 AP firmware are not same. So failing over between these two WLC will be same as doing AP fail over between two 5508 having different software version. (ie AP has to download the image & reboot every time). Also I would suggest you to start this migration step by step as you need to be familiar with this converged access setup (how it works & troubleshoot issues). I would setup 5760 & move one building AP to this CA & monitor it for 2-3 months & them move on.
Here are the answer to other queries you have.
1. After enabling new mobility in the 5508.
Will I still be able to use flexconnect mode for the remote locations? I know the 5760 doesn't support flexconnect mode, but I'm not sure if the flexconnect feature is not supported in a converged access deployment.
Yes, 5508 support FlexConnect irrespective of "new mobility" feature enable or not. Here is how you configure new mobility & peer a 5760 to a 5508. You need to have 7.6.x or 8.x code on your 5508 to do this.
http://mrncciew.com/2014/05/06/configuring-new-mobility/
2. Will I be able to manage and configure everything in the 5760 (MC) and the WLC will push the configurations, WLANS, settings, etc to the 3850s (MA)? Or do I also need to configure WLANS, etc on each individual 3850?
I do not think you can do this yet, Cisco will make this happen in future. So you have to configure each & every MA identically. If you have prime, then IOS-XE 3.7.x onward it support template configuration. But IOS-XE 3.7 is recently released,so cannot guaranteed the stability. (I am using 3.6.1E in my production). Below post will give you some starting point on this configuration
http://mrncciew.com/2013/12/14/3850ma-with-5760mc/
3. Current license count in the 5508 is at 350 APs.
The new deployment will have 10 3850s with 5 AP licenses per switch and the 5760 will come with 25 AP licenses. That's a total 75 AP licenses.
I would need to purchase 225 additional licenses on the 5760 to make a total of 350 AP licenses.
Will I be able to move the switches' AP licenses to the 5760 to make 350 AP licenses?
In the CA setup, licence only required at MC, not in MAs.It is right to use license model & Cisco trust what you configure is what you purchase (no license key/serial number like in 5508/2504/etc). Refer this for some detail
http://mrncciew.com/2013/12/12/getting-started-with-5760/
Like said earlier, start in small scale & get familiar with new setup, my blog may give some other useful posts on this converged access.
Let us know if you have further queries on this & happy to help
HTH
Rasika
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