Optimized Roaming vs Client Roaming

[jmajerick]

Cisco 7510 WLC - Having an issue at one site where device has to get a poor signal before hopping to the next access points.  This is on the 2.4GHz band and all speeds below 11Mbps have been disabled.

My question is for someone to explain the difference between Optimized roaming and Client roaming.  Also, which is the preferred method?

Thank you!

[Ric Beeching]

In general the decision to roam is up to the client and most devices have their own proprietary algorithms that decide when to do this. Apple devices are notorious for "sticking" to a single AP even if its signal is weak and there is a stronger signal from another AP.

You can manipulate devices and persuade them to move earlier through a couple of different methods but at the end of the day it is still the client making that decision to move.

Optimised roaming via 802.11k works IF your devices support it so that would be something to check. It may just be a driver update for your devices but other times they may just not support it.

This is quite useful for a more in depth explanation:

http://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/5700/software/release/ios_xe_33/11rkw_DeploymentGuide/b_802point11rkw_deployment_guide_cisco_ios_xe_release33/b_802point11rkw_deployment_guide_cisco_ios_xe_release33_chapter_010.html

Other ways would be disabling lower rates as you already have done or lowering the power on the 2.4GHz radio. This will lower your cell size and essentially force your devices to roam as the cell edge becomes unsustainable for the higher rates you've specified.

For preferred method there isn't one as each situation is unique (sorry bit of a cop out there) so i comes down to finding the right balance for your devices in use.

Cheers,

Ric

[WiFi Trainers]

Hello,

There are two primary differences between optimized roaming and client roaming:

Optimized roaming is something that is enforced on the AP. For ex if we say that "Optimized Roaming Data Rate Threshold" is set to 24 Mbps, then the client cannot connect unless it has an RSSI value which is good enough to maintain a 24 Mbps connection. An existing connection is also dropped if this threshold is reached. The second point is that this enforcement is done for all types of clients.

Client roaming on the other hand works with only CCX (cisco compatible extension) clients. Apple clients for ex will not support this. This is not enforced by the AP. Meaning it is upto a CCX enabled client to roam to a new AP when its signal strength drops below the RSSI threshold. If the client continues to stay connected the AP will not drop it.

Now regarding what to enable:

Optimized roaming needs to be deployed only when you know you have a very well deployed network with correct overlapping coverage. Otherwise you will start seeing client drops.

Client roaming can be enabled and will not cause any negative impact. It is just not understood by all types of clients.

Hope this helps.

Best Regards,

www.wifitrainers.com

Learn from the Best To be the Best!

Change the way you look at wireless client connectivity forever by registering to watch this free webinar and also stand a chance to win our Wireless starter kit worth $8000 for free!!

[Blazej Pawlak]

On Wlc software 8.2.164 we have encountered an issue where cisco optimize roaming (wireless -> advance > optimize roaming) caused disconnection during Skype or WebEx calls (Basically with real time traffic introduced to data exchange ). This was cause with clients that used Intel N 7265 NIC cards we still did not receive replay from TAC but just a precaution when you see out of reason disconnection check your settings.

[Scott Fella]

Curious to see what TAC has to say since they will review your configuration. I don’t have any or no anyone whom is using that feature. Was there an issue prior that made you decide you needed that feature?  Typically with voice/video, you don’t want to introduce features that disassociate or suppresses client from connecting.