Default beacon/dtim settings

[Trent Hurt]

What are folks thoughts regarding increasing the beacon interval as well as the dtim interval on a very large byod data ssid? I know the dtim increases for voice but I'm interested in upping those settings on regular data ssid.

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[thefranmanatt]

are you able to sniff traffic? 

You may free up some air time disabling those probe suppressing hacks.

Do you have a WCS/NCS/CPI?

What code are you running?

Read over that HD guide George posted.  It is a good.  Aruba and Aerohive have HD guides worth reviewing also.

FYI,  10-20 seconds after the screen goes black on iphones/ipads they pretty much shut down the wifi.  When they are on you would real want them connected so they aren' probing EVERY channel (even the off ones like 2,3,4,5,7,8,9,10), this really slows down their probing.  Ever AP that hears the probe replies,  If you have 6 aps on channel 1 and they hear the probe they'll all reply.  The newer ios version probe at 6mbps.

Kills off the lower rates like 6,9,12, and maybe 18.  Add more 5GHz only APs.

CCNP - Wireless
CWNA and CWAP

[Trent Hurt]

are you able to sniff traffic?
Yes, I said that in earlier post. What are you asking?

You may free up some air time disabling those probe suppressing hacks.

????

Do you have a WCS/NCS/CPI?
PI

What code are you running?
7.4
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[thefranmanatt]

If you can sniff the traffic you may want to look at the "QBSS" to see change utilization.  Also you can check the beacon to make sure they are getting spit out even 102.4ms.  The AP has to content to send it out, so if it the medium is busy you'll see delayed beacons.  Though after so many delayed beacons will give itself better chances to access the medium (I forget the details)

Disable load balancing and band select. those are hacks.

In CPI you can run channel utilization reports. This will help you see airtime use

In 7.2 they added a way to limit users per radio.  I'd set the 2.4GHz fairly low.  This will help move dual band client over to 5GHz.  It does run the risk of 2.4GHz users not getting access. In 7.4 you can enable AVC and watch traffic patterns.  Give proiaty to the important class stuff and BE the unimportant stuff like facebook etc.

You may want to set up two SSIDs, a fast and a slow.  Make the fast SSID 5GHz only.  Users that can see it join it instead of getting on the 2.4 radios.  Also I'd make the 5GHz 40MHz, this will allow clients that support it use less airtime.  Make sure you select your 5GHz channels to match a large % of what you clients support.  If only 10% of your clients support unii-2 extended... well don't enable those channels.

CCNP - Wireless
CWNA and CWAP

[George Stefanick]

+5 Kevin

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[George Stefanick]

Although I agree with Kevin on most of his comments to pull every last piece of bandwidth (fine tuning) but very rarely comes down to this for most folks in my experience. Not everyone nerd knob like we do ;)

Stick to the very basics first. Small cells, shape rf with direction antennas (this is a big one here and may cause you to swap out aps), low power. These 3 items right here will have a big impact on clients. I'm thinking you might be using integrated antennas or omnis today. If so, you will see a day and night difference when you swap antennas and place the aps properly.

The big issue here is how clients react and designing for them. The above limits their ability to think for themselves and takes some of their poor decision making process out of the equation. The less aps they see (or lower power ones) the better.

Good experience is a ahead my friend! Not a lot of folks get this kind of exposure enjoy the ride!

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[George Stefanick]

Really N E r d K N o b is a bad word ! ??

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[Scott Fella]

George is funny:) Heck, I tweak those every time at all my clients and it varies depending on what the environment looks like. Your worse off leaving the defaults.

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[mmangat]

Hello,

The Beacon Interval specifies the duration between beacon packets.   Access Points broadcast Beacons or Traffic Indication Messages (TIM) in  order to synchronize wireless networks.   The default setting of 100  should be ideal for most situations.  In a "noisy" environment - one  with much interference - decreasing the Beacon Interval may improve  network performance.  In very remote locations (with few wireless nodes)  this value may be increased.

DTIM Interval

This setting determines how often the Access Point's Beacon (TIM)  contains a delivery traffic indication message (DTIM). The DTIM tells  client devices in power-save mode that a packet is waiting for them. The  default setting causes client devices using power-save mode to wake up.  To conserve battery power in client devices using power-save mode,  increase the Data Beacon Rate (DTIM) setting.  However, setting the DTIM  too high may cause a wireless client to lose its network connection.

The DTIM is a multiple of the Beacon (TIM).  So if the DTIM was set to  3, a DTIM message would be sent with every third Beacon.

[George Stefanick]

Wonder if these Cisco guys are real or drones with auto reply with subject definitions ..



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[Amjad Abdullah]

LoL. They are real

but they copy and paste.

Rating useful replies is more useful than saying "Thank you"