What is the meaning of slow in roam type 802.11i?

[id404]

What is the meaning of slow in roam type 802.11i?

[marce1000]

  - Presumably this denotes the opposite of 802.11r (FT)  (not fast roaming)

 M.

[Flavio Miranda]

Hi

 This suppose to be a problem. Even if Fast roaming enable I've seen it before. 

 The Fast roaming by the way is sligh faster only. 

 This log is trying to say that you may have a problem. It can be high interference,  high channel utilization, slow clients etc. 

 But, in my opinion,  make sense worrry about it if you have users complains. Because this can easily be a falsa positive. 

 The WLC also show how long the roaming is taking in miliseconds. 

[MHM Cisco World]

are the roaming happened between same AP model ?
if not please list both AP model 

[Rasika Nayanajith]

"slow roam" mean that client has to go through the full authentication process, every time the client moves from one AP to another. See the below diagram, when the client moves from AP1-> AP2 ->AP3, it has to go through full authentication as PMK is not cached at new APs. But when client roam-back to previously associated APs, then it can use cached PMK

When you implement the Key Caching method (eg OKC), it will be a fast roam for subsequent roaming (except first association to the network). See the below diagram. In this case, WLC shared the PMK with AP2 & AP3, so they can straight go to 4-way handshake without deriving PMK through full 802.1X frame exchange.

802.11r (Fast Transition) is a standard-based method to implement fast roaming, Refer below if you are interested to see details

https://mrncciew.com/2020/12/10/fast-roaming-lessons/ 

HTH

Rasika

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[DMAC1000]

Rasika,

    I love your documentation.  I was wondering if you have a good way to see what clients are capable of as far as roaming protocols?  For example, I have ascom phones in my environment and I am worried that turning on OKC or 802.11r would potentially cause more issues on the network for those clients.

[Rasika Nayanajith]

Hi DMAC1000,

Client devices roaming support to be checked with its vendor documentation. It is a good idea to check that and get some validation before enabling 11r. Most of smartphones, tablets, laptops support 11r nowadays and should not have any problem with those devices.

Cisco WLCs point of view 9800 will do OKC by default (AireOS WLCs are doing SKC or PMK caching). Standards point of view use of 11r is the recomendatin.
HTH
Rasika
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[Leo Laohoo]

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@DMAC1000 wrote:
I have ascom phones in my environment and I am worried that turning on OKC or 802.11r would potentially cause more issues on the network for those clients.

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What is the exact model of ASCOM phones and what firmware?

I have a fleet of i62 and we are slowly transitioning to i63.

[DMAC1000]

I62 and we have about 1000 that were slowly trying to move to i63. If youve had any experience with FT on them let me know. I dont remember the version.

Thanks
Dave

[Leo Laohoo]

I do not have remote access to our WLC during the weekend so I will check the specifics. 

If I remembered correctly, the i62 is "dumber" than the i63, so our i62 joins an SSID with PSK.  However, the i63 has some improvements and it joins a "normal" corporate SSID with Dot1X.

[DMAC1000]

Were doing 802.1x peap with i62s

[Leo Laohoo]

Does your i62 connect to 2.4 Ghz or 5.0 Ghz? 

If primarily on 5.0 Ghz what channels are allowed?

[DMAC1000]

2.4Ghz.. my other fear of putting them on 5 was the channel support.

[Leo Laohoo]

8 useable channels (5 Ghz) vs 3 useable channels (2.4 Ghz).

Funnily enough, we were the first to lobby ASCOM to release an InterOp guide for 5.0 Ghz when "everyone else is happily using 2.4 Ghz".   (Granted, our local ASCOM reseller were as useless as an anvil in a parachute even though one of their partner makes a living killing with AP placement designs.)

[DMAC1000]

Yes i put in a support ticket on Thursday. Here i am on saturday. It was just a request for this FT information. How hard can it be to answer a spec question over email.