Wireless Access

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Re: 2.4GHz - High average channel busy

Beisdes what Collin and i telling you

 

I would like to know if your enviroment is a high density envirtoment

 

If it is you should consider

 

1-Turn on Airtime fairness if you havent

2-Take a look on how many users are connnected per band on one AP( let say if you using internal applications and you got like 50 users on one band you surely willl have issues in that AP)

3-If its possible use VLan poolin with small vlans of /24, try not passing of 10 vlan pools mapped to 1 SSID

4-Make sure you please get rid of that many SSIds,  Bealive you will be able to work with 2 or 3 SSIDs if you use 802.1x and derived roles... if you already using 802.1x and not using derived roles consider using it so you can get rid of that many SSIDs.

5-Consider doing Link aggregation between the controller and the Switch you are plugging it, this will help you to have fail over and also if you got HIGH traffic to evade bottle necks

6-Be sure you are connecting ALL the APS to ports of 1000 and also that they syncronized on speed of 1000( you can see that by cli and well you can also see that by lookin at the ap, if the enet power led is not green, and is like orange, then its connected at 100 and you will have a bottle neck there.

7-Turn on like Collin told you filter broadcast and multicast

8-Block Chatty protocols if you can, like bonjour, on the wireless ports.

 

 

This is asumming you got all in the same site and you dont have multisites, which then ill need to know to give more recommendations

 

Cheers

Carlos

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Project engineer
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Trusted Contributor I

Re: 2.4GHz - High average channel busy

cjoseph,

 

My only concern about turning an AP into airm monitor mode is that I'll lose the 5GHz radio as well, right?  An AP can't be in AM mode for one band and serve clients in the other band, right?

 


@NightShade1 wrote:

Beisdes what Collin and i telling you

 

I would like to know if your enviroment is a high density envirtoment

 

If it is you should consider

 

1-Turn on Airtime fairness if you havent

2-Take a look on how many users are connnected per band on one AP( let say if you using internal applications and you got like 50 users on one band you surely willl have issues in that AP)

3-If its possible use VLan poolin with small vlans of /24, try not passing of 10 vlan pools mapped to 1 SSID

4-Make sure you please get rid of that many SSIds,  Bealive you will be able to work with 2 or 3 SSIDs if you use 802.1x and derived roles... if you already using 802.1x and not using derived roles consider using it so you can get rid of that many SSIDs.

5-Consider doing Link aggregation between the controller and the Switch you are plugging it, this will help you to have fail over and also if you got HIGH traffic to evade bottle necks

6-Be sure you are connecting ALL the APS to ports of 1000 and also that they syncronized on speed of 1000( you can see that by cli and well you can also see that by lookin at the ap, if the enet power led is not green, and is like orange, then its connected at 100 and you will have a bottle neck there.

7-Turn on like Collin told you filter broadcast and multicast

8-Block Chatty protocols if you can, like bonjour, on the wireless ports.

 

 

This is asumming you got all in the same site and you dont have multisites, which then ill need to know to give more recommendations

 

Cheers

Carlos


1. Is enabled.  Set to fair access.

2. It's about a 50/50 split.  However, 3/4 of total sessions calculated for a week are on 5GHz.

 

3. I've thought about using VLAN pools, but wasn't sure what the benefit would be. I will definitely consider doing this.

 

4. I ran another test today and disabled 3 SSIDs that are hardly in use.  I noticed a HUGE decrease in utilization on 2.4GHz.  We're working on a ClearPass implementation and I plan to get rid of the 3 extra SSIDs when we go live.

 

5. I don't believe we're saturating this link, but still a good suggestions.

 

7. Filter Bc/Mc is already enabled.

 

I think getting rid of the extra SSIDs is going to be one of the best things we can do to decrease 2.4GHz utilization, as testing has confirmed. I appreciate all of the suggestions you guys have made!

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Re: 2.4GHz - High average channel busy

Good to hear its better now :)

 

I have seem many places having 4, 5 even 6 SSIDs... and its terrible..

 

Anyways about the  mode aware  arm feature you can turn it on just on 2.4ghz band if you want...

Go to ap group-->RF managment-->802.11g radio-->Adaptative Radio managment  and you can check the feature.... just on the 2.4ghz...

 

I would say that if you want to be really sure it does not impact your clients you can always test it on weekends :)  and see how it goes,  Remenber it does it automaically, you can do it manually like Collin Suggested.  :)

 

 

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Project engineer
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Re: 2.4GHz - High average channel busy

ah yeah you never told me how many users you got per AP...

Iill give you some tips

 

Recommended if you just using wireless for  websurfing and light stuff inside the company, for each radio you should not pass more than 30 user, it is recommeded... Yes you can always have more  but remenber that in wireless this is a half duplex and wireless is CSMA...

So dont think that all the laptops are transmitting at the same time... just one its transmitting... Just imaging that big line of devices wainting for their turn?

That being said also remenber that 300Mbps in one band is not really that is more  150 Mbps once overheads are extracted) 

You have to take many things in consideration!

 

 

 

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Project engineer
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Trusted Contributor I

Re: 2.4GHz - High average channel busy

Ah sorry about that.  At the most we may have around 15 users per AP.

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Re: 2.4GHz - High average channel busy

You should not have issue for that part then :)

 

There are many things you can do to tune up your wireless :)

 

Anyways let see how it goes without those 3 extra SSIDs :)

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Project engineer
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Aruba Employee

Re: 2.4GHz - High average channel busy

For each SSID we have to transmitt a beacon and we send these at the lowest configured rate by default.

So four / five SSID's is 4/5 beacons at 1mbs every 100ms.

+ you then have background traffic and again have to transmitt mcast/bcast at the lowest configured rate (by default - lots of config options available)

 

I personally would get a Wi-Fi packet capture to see what is being transmitted in the Air, it might be as simple as increasing the lowest rate to 6mbs or something like enabling broadcast-filter.

 

 

 

View solution in original post

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Trusted Contributor I

Re: 2.4GHz - High average channel busy

Giles was spot on.  After removing 802.11b data rates, channel utilization is now on average below 20% utlization for all APs.  HUGE improvement!

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Occasional Contributor I

Re: 2.4GHz - High average channel busy

This outlines the issue we are seeing on campus. Just curious if anyone knows off the top of their head if the wired ports on a 93H will still function if the ap is in AM mode?
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