Solved: Can I choose 40 MHz channels for 5.2 GHz and 20 MHz for 2.4 GHz simultaneously? - Page 2

keithsauer507 · ‎07-03-2013

I have a 5508 WLC and 6 3500 LAP's at the main office, 2 at another office and 2 at yet another office.

I noticed that even when I specify 5.2 GHz on my wireless adapter (Intel Centrino Advanced-N 6230) It says the data rate is 144 Mbps. I want to try to get 300 Mbps out of it and I believe I have to enable 40 MHz wide channels in the 5.2 GHz range. Well I don't want to cause any network disruption to currently associated clients. Is this something I can do? What if a client adapter does not support 40 MHz wide channels? Can I keep 2.4 GHz at 20 MHz wide channels and then they would just connect to the 2.4 GHz freqency range?

Where would I go to change the channel width for 5.2 GHz only? Is it set globally or do I set it for each AP? I did see a radio button for 20 MHz or 40 MHz in this location: Wireless > 802.11a/n > RRM > DCA

Is this where I would make the settings change? If I do this would it bump clients off the network briefly? Do all 802.11n adapters with 5.2 GHz radios support 40 MHz channels?

Looking at the channel usage with a program called inSSIDer 3, there isn't anything going on in the 5 GHz band except for us.

Thanks for the help. Just looking to get the best possible network throughput as I've had some SMB based applications respond slowly or poorly when on wireless connections... even when the OS reports 144 Mbps.

Scott Fella · ‎07-05-2013

My iPhone 5 was able to connect. Had some trouble authenticating, but I did a "forget this network" and re-created it and it got online fine.

This is normal and I have to do this when I change WLAN configuration at times, especially if you had the SSID broadcasting and then you remove it or if you change the security.

I enabled band select, disabled the 802.11a, enabled 40 MHz and the extended UNII-2 channels, 802.11h channel announcement and channel quiet mode, CCX Location Measurement and then re-enabled the 802.11a network.

Be careful with band select as some devices will fail to associate to the AP... I have seen this so you just need to monitor. I don't typically set this because the client will still make the decision and my macbook pro will prefer the 2.4ghz. UNII-2 extended should be disabled since many devices don't suppor these channels yet. Clients that roam to an AP with these channels witll fail and it will seem like a coverage gap.

Not seeing any issues on the Intel or Dell wireless adapters out there so far.

Thanks,

Scott

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-Scott
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keithsauer507 · ‎07-05-2013

Thanks for the tips. Maybe next maint. window I will turn off the UNII-2 extended channels. I think there was a pop up when I enabled 40 MHz that eluded to the fact that I should enable extended channels, so that is why I did.

Anyway here is some jPerf results from my laptop to my desktop.

Gigabit LAN Laptop to Desktop

ID] Interval Transfer Bandwidth

[288] 0.0- 1.0 sec 28.4 MBytes 28.4 MBytes/sec

[288] 1.0- 2.0 sec 28.1 MBytes 28.1 MBytes/sec

[288] 2.0- 3.0 sec 27.9 MBytes 27.9 MBytes/sec

[288] 3.0- 4.0 sec 28.1 MBytes 28.1 MBytes/sec

[288] 4.0- 5.0 sec 27.9 MBytes 27.9 MBytes/sec

[288] 5.0- 6.0 sec 28.3 MBytes 28.3 MBytes/sec

[288] 6.0- 7.0 sec 28.1 MBytes 28.1 MBytes/sec

[288] 7.0- 8.0 sec 28.2 MBytes 28.2 MBytes/sec

[288] 8.0- 9.0 sec 28.7 MBytes 28.7 MBytes/sec

[288] 9.0-10.0 sec 28.9 MBytes 28.9 MBytes/sec

[288] 0.0-10.0 sec 282 MBytes 28.2 MBytes/sec

802.11n 5.2 GHz (Windows reporting 300mbps sync)

[ ID] Interval Transfer Bandwidth

[288] 0.0- 1.0 sec 6.62 MBytes 6.62 MBytes/sec

[288] 1.0- 2.0 sec 6.50 MBytes 6.50 MBytes/sec

[288] 2.0- 3.0 sec 4.73 MBytes 4.73 MBytes/sec

[288] 3.0- 4.0 sec 6.18 MBytes 6.18 MBytes/sec

[288] 4.0- 5.0 sec 4.84 MBytes 4.84 MBytes/sec

[288] 5.0- 6.0 sec 5.49 MBytes 5.49 MBytes/sec

[288] 6.0- 7.0 sec 6.09 MBytes 6.09 MBytes/sec

[288] 7.0- 8.0 sec 6.16 MBytes 6.16 MBytes/sec

[288] 8.0- 9.0 sec 6.14 MBytes 6.14 MBytes/sec

[288] 9.0-10.0 sec 6.71 MBytes 6.71 MBytes/sec

[288] 0.0-10.0 sec 59.5 MBytes 5.95 MBytes/sec

Laptop connected to 100mbps ethernet port.

[ ID] Interval Transfer Bandwidth

[296] 0.0- 1.0 sec 4.81 MBytes 4.81 MBytes/sec

[296] 1.0- 2.0 sec 4.67 MBytes 4.67 MBytes/sec

[296] 2.0- 3.0 sec 4.91 MBytes 4.91 MBytes/sec

[296] 3.0- 4.0 sec 5.13 MBytes 5.13 MBytes/sec

[296] 4.0- 5.0 sec 5.30 MBytes 5.30 MBytes/sec

[296] 5.0- 6.0 sec 5.13 MBytes 5.13 MBytes/sec

[296] 6.0- 7.0 sec 5.06 MBytes 5.06 MBytes/sec

[296] 7.0- 8.0 sec 4.51 MBytes 4.51 MBytes/sec

[296] 8.0- 9.0 sec 4.97 MBytes 4.97 MBytes/sec

[296] 9.0-10.0 sec 5.03 MBytes 5.03 MBytes/sec

[296] 0.0-10.0 sec 49.6 MBytes 4.95 MBytes/sec

So it is slightly faster than 100mbps ethernet. Wish I could get it closer to the gigabit lan speeds, but I guess we will have to wait for 802.11ac for that.

Scott Fella · ‎07-05-2013

You still need to look at over subscribing the gigabit port. The more users you have on that AP the less the throughput you may see.

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-Scott
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keithsauer507 · ‎07-05-2013

At our main site we have 6 AP's. (GigE LAN), 2 AP's at a remote site (10mb WAN) and 2 more at another remote site (30mb WAN). Cisco 5508 has 4 GigE ports trunked to 3750 gig switch.

Though the 40mhz channel did improve throughput. Better than I get at home with residential grade stuff at least.

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