Data Rates, Mandatory/Supported/Disabled?

[tom.hill]

Hi Guys,

I have recently had issues with clients disconnecting (made obvious by Outlook refusing to connect back up to Exchange after creating over 32 sessions) and also N clients not being able to connect at over 54Mbps or just not being able to achieve a stable connection... I'm just having a nose around my WCS and noticed that the data rates are set to:

802.11a/n > Parameters

6-24 Mbps Disabled

36 Mbps Mandatory

48+54 Supported

802.11ba/n > High Throughput(802.11n)

802.11n Network Status (ticked)

7-29 Mbps (unticked)

43-144 Mbps (ticked)

802.11b/g/n > Parameters

1-24 Mbps Disabled

36 Mbps Mandatory

48+54 Mbps Supported

802.11b/g/n > High Throughput(802.11n)

802.11n Network Status (ticked)

7-29 Mbps (unticked)

43-144 Mbps (ticked)

Is this a typical set up? It seems like it would make sense to support as many data rates as possible so clients step down instead of being disconnected? Not sure why N can't connect at higher speeds then 54Mbps though as the higher data rates are selected...

I wonder if anyone could shed some light on the disabled/mandatory/supported settings also, I found this description of the settings:

Mandatory—Clients must support this data rate in order to associate to an access point on the controller.

Supported—Any associated clients that support this data rate may communicate with the access point using that rate. However, the clients are not required to be able to use this rate in order to associate.

Disabled—The clients specify the data rates used for communication.

Mandatory and Supported options make sense, but the explanation of disabled confuses me! Can clients still connect up to a data rate that has been disabled?

Network consists of:

11 1252AG AP's (software version v7, IOS 12.4)

1 4402 WLC (v7)

1 WCS (v7)

1 ACS (v5)

1 Bluesocket Controller (for guest access)

Thanks for reading.

Tom

[Surendra BG]

Hi,

To get the N Speeds, make sure that we have the below conditions..

1>> Open auth with no encryption with all MCS rated enabled with WMM enabled.

2>> WPA2 Auth (Either ENterprise or PSK) with AES as the Encryption (TKIP = N Not supported) , with All MCS rated enabled with WMM enabled.

And make sure you leave the datarates for default.. Higher the MANDATORY , The clients should support the mandatory to get the connectivity.. since you have disabled the lower rates!!

I guess the client connectivity what ur facing is kinda expected with the below settings that yo have configured... when there is light fluctuations, the client will disconect.. make sure you have default setting on the Datarates and see if that helps..

Regards

Surendra

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[tom.hill]

Hi Surendra,

Many thanks for your reply.

I have WPA and WPA2 enabled both with AES and TKIP, do I have to expressily disable WPA and TKIP to get the faster 802.11n speeds? Or just ensure that the clients are connecting using WPA2 and AES to take advantage of the faster speeds?

I have WMM 'Allowed' is this enough or does it need to be 'Required'?

What are the default data rate settings? All set as 'Supported'?

I must be missing a default settings button somewhere!

Tom

[tom.hill]

I think I might have found a problem, I'm powering the AP's using PoE, and although I can't see any warnings etc on the WCS, on the WLC directly I read:

PoE Status:     Medium Power (15.4 W)

Which doesnt sound too bad however after a bit of a Google:

http://www.cisco.com/en/US/docs/wireless/controller/5.2/configuration/guide/c52lwap.html

•20.0 W (Full Power)—This mode is equivalent to using a power injector or an AC/DC adapter.

•16.8 W—Both transmitters are used but at reduced power. Legacy data rates are not affected, but the M0 to M15 data rates are reduced in the 2.4-GHz band. Throughput should be minimally impacted because all data rates are still enabled. The range is affected because of the lower transmit power. All receivers remain enabled.

•15.4 W—Only a single transmitter is enabled. Legacy data rates and M0 to M7 rates are minimally affected. M8 to M15 rates are disabled because they require both transmitters. Throughput is better than that received with legacy access points but less than the 20 and 16.8 W power modes.

•11.0 W (Low Power)—The access point runs, but both radios are disabled.

Looks like i'm going to be plugging my power injectors back in!

Tom