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Best Practice Access Points and WLC Migration

fiestas.cesar
Level 1
Level 1

Hello Experts,

 

I have a client that currently have 2 5520's with several older access points 3500/3700's. We are going to be replacing them with 3800 series/1562's access points.

We understand that we cannot upgrade the WLC at once because we would loose or have issues with the 3500's series access points if we were to take the WLC's to a higher version.

These WLC's serve thousands of users hence we want to have an smooth access point replacement. As such what would be the recommended process, oh I forgot to mention, we have new 5520's that we want to use for this purpose, meaning to host the new access points and infrastructure.

I guess what we are trying to achieve is to have the WLAN's working as usual while we replace the 3500/3700 series access points phase by phase.

Should we move all the exisiting (older) access points to the new WLC's THEN replace first the 3500's access points with the 3800's and then upgrade the WLC's to a higher code?  or? 

Because we could keep some access points in the older 5520's and some in the new 5520's as long as the mobility groups are the same then the devices wont have issues with roaming, etc

I will appreciate your comments on what would be the best approach thanks!

 

 

7 Replies 7

David Ritter
Level 4
Level 4

UM,  8.5.140.0 code supports both 3500 and 3700 ap's as well as 3800 and 1560's

I currently support that combination myself.

I suspect the problems you will experience will be insuffient POE to the 3800's.  I had to use 2800's in some locations.

The 3800's require a full 30w at the end of the run so if it only gets 28.5 due to poe line loss it will not energize.  The 2800's only need 26.1w

David,

 

Thanks for your response, indeed we are aware of the poe+ requirement of the 3800's AP so i think we got that part covered, we are actually using 3850's switches to support these AP's.

Leo Laohoo
Hall of Fame
Hall of Fame
Leave the old APs connected to the old controller.
Stand up the new controller and provision the new APs to connect to the new controller. it doesn't mean the AP will be installed. Just allow it to download the firmware and allow you to configure different AP-specific settings (like Name, Location, AP Group, etc.).
Once this is done, replace the APs one by one.

Leo,

 

Thanks for your response, although I am not sure what is the benefit of doing this?

As mentioned before my client have an existing pair of 5520's and he also has an extra pair of 5520's that he wants to replace with.

On the existing production pair of 5520's he has few hundreds 3502's and 3702's. He has also purchase few hundreds of 3802's that he will use to replace the 3502's and the 3702's.

 

The idea is to minize the impact on the WLAN while replacing/adding access points. One thought was to standup the new pair of 5520's to allow the new 3802's to register and configured while having the old pair of 5520s to continue working, but for example wouldnt this affect a client that is register to a 3502 in the old pair of 5520's and suddendly moves or roams to a 3802 that is register to the new pair of 5520's? Thanks

 

Ok, let's turn this around: Is the site 24 x 7 operation?

Leo,

 

Correct this is 24x7 site P1. 

Ok, for hospitals ... Upgrading an AP, like-for-like, is taking one down and slapping the fresh one in.
2800/3800 boots up in about 5 minutes. Add join time to a controller of about 90 seconds.
(Downloading the firmware is not included in the equation because I advocate pre-provisioning the APs before undertaking the swap-out.)
Now, how many people will be taking the down the AP simultaneously? I presume one.
So this means that if a site or a floor has very adequate wireless coverage, then swapping out the APs one-by-one won't really cause a significant impact. When it comes to roaming, unless the medical staff are connected to their phone ALL THE TIME and doing voice/video calls, I still don't see any difference about "zero impact".
It can be done. If an AP goes down, the wireless clients will either find the next nearest AP from the same floor or the floors above/below.
At the end of the day, if the wireless clients' wireless NIC drivers are up-to-date, then the roaming "algorithm" is significantly improved. It is those wireless clients that are still "locked down" to Windows XP or Vista or 8 (and cannot be upgraded) that will be a significant risk. And if this is present, then my advice is to push the CoWs to a corner and connect them to the network with a patch cable until the APs are upgraded to a degree that they will be able to "roam" to the new APs.
I hope this makes some sense.
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