Tuesday, January 6, 2015

Cisco Wireless Access Point 5GHz Transmit Power Reference

UPDATE: 05-Oct-2015

Thanks to Tim Dennehy, CWNE #94 (@JustDoWiFi), for loaning me a Cisco 3502 and 3602, the list has been updated with these two additional Access Points.

Here is the link to the updated PDF Document.

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George Stefanick aka @wirelesssguru, who runs my80211.com, posted a blog here on the different transmit power levels in the 5 GHz band for the various channels on Cisco Wireless Access Points.  There were several comments, with one looking for a reference list.  This post will hopefully fill that void for the Cisco Wireless Access Points available to me at that time.

In compiling the list, each available Wireless Access Point was connected to a Cisco 2504 Controller, running 7.6.100.0.  As a result of seeing variable output powers within the UNII-3 band for the Cisco 1242, each channel on each Wireless Access Point was configured and had a Client successfully Associate prior to confirming the transmit power settings for that specific channel.

The following configuration steps were taken:
  • Disable the 802.11a radio on the applicable Cisco Wireless Access Point
  • Change the 802.11a channel
  • Enable the 802.11a radio on the applicable Cisco Wireless Access Point
  • Display the 5 GHz Cisco Wireless Access Point configuration
The following commands were run:
  • > config 802.11a disable <APName>
  • > config 802.11a channel ap <APName> <channel#>
  • > config 802.11a enable <APName>
  • > show ap config 802.11a <APName>
Below are tables of the consolidated results for the following Cisco Wireless Access Points:
  • Cisco 1131
  • Cisco 1242
  • Cisco 1142
  • Cisco 2602
  • Cisco 3502
  • Cisco 3602
  • Cisco 3702


Cisco 1131
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 60, 64100, 104, 108, 112, 116, 132, 136, 140149, 153, 157, 161
Power Level
115 dBm17 dBm17 dBm17 dBm
214 dBm15 dBm15 dBm15 dBm
311 dBm14 dBm14 dBm14 dBm
48 dBm11 dBm11 dBm11 dBm
55 dBm8 dBm8 dBm8 dBm
62 dBm5 dBm5 dBm5 dBm
7-1 dBm2 dBm2 dBm2 dBm
8-1 dBm-1 dBm-1 dBm


Cisco 1242
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 6064100, 104, 108, 112, 116, 132, 136, 140149, 153157161
Power Level
111 dBm17 dBm11 dBm17 dBm17 dBm14 dBm11 dBm
28 dBm15 dBm8 dBm15 dBm15 dBm11 dBm8 dBm
35 dBm14 dBm5 dBm14 dBm14 dBm8 dBm5 dBm
42 dBm11 dBm2 dBm11 dBm11 dBm5 dBm2 dBm
5-1 dBm8 dBm-1 dBm8 dBm8 dBm2 dBm-1 dBm
65 dBm5 dBm5 dBm-1 dBm
72 dBm2 dBm2 dBm
8-1 dBm-1 dBm-1 dBm


Cisco 1142
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 60, 64100, 104, 108, 112, 116, 132, 136, 140149, 153, 157, 161, 165
Power Level
114 dBm17 dBm17 dBm17 dBm
211 dBm14 dBm14 dBm14 dBm
38 dBm11 dBm11 dBm11 dBm
45 dBm8 dBm8 dBm8 dBm
52 dBm5 dBm5 dBm5 dBm
6-1 dBm2 dBm2 dBm2 dBm
7-1 dBm-1 dBm-1 dBm


Cisco 2602
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 60, 64100, 104, 108, 112, 116, 132, 136, 140149, 153, 157, 161, 165
Power Level
114 dBm17 dBm17 dBm23 dBm
211 dBm14 dBm14 dBm20 dBm
38 dBm11 dBm11 dBm17 dBm
45 dBm8 dBm8 dBm14 dBm
55 dBm5 dBm11 dBm
68 dBm
75 dBm


Cisco 3502
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 60, 64100, 104, 108, 112, 116, 132, 136, 140149, 153, 157, 161, 165
Power Level
117 dBm17 dBm17 dBm17 dBm
214 dBm14 dBm14 dBm14 dBm
311 dBm11 dBm11 dBm11 dBm
48 dBm8 dBm8 dBm8 dBm
55 dBm5 dBm5 dBm5 dBm
62 dBm2 dBm2 dBm2 dBm
7


Cisco 3602
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 60, 64100, 104, 108, 112, 116, 132, 136, 140149, 153, 157, 161, 165
Power Level
114 dBm17 dBm17 dBm23 dBm
211 dBm14 dBm14 dBm20 dBm
38 dBm11 dBm11 dBm17 dBm
45 dBm8 dBm8 dBm14 dBm
52 dBm5 dBm5 dBm11 dBm
62 dBm2 dBm8 dBm
75 dBm
82 dBm


Cisco 3702
UNII-1 UNII-2 UNII-2e UNII-3
36, 40, 44, 4852, 56, 60, 64100, 104, 108, 112, 116, 132, 136, 140149, 153, 157, 161, 165
Power Level
115 dBm17 dBm17 dBm23 dBm
212 dBm14 dBm14 dBm20 dBm
39 dBm11 dBm11 dBm17 dBm
46 dBm8 dBm8 dBm14 dBm
53 dBm5 dBm5 dBm11 dBm
62 dBm2 dBm8 dBm
75 dBm
82 dBm

Wednesday, November 5, 2014

Get on up to the 5GHz side! - Change OSX WiFi over to an available 5GHz Channel or any other Channel

Traveling on the road a lot, it's typical to get a Hotel and see, well not the greatest of WiFi designs.  On this latest trip I got to my hotel room, popped open Metageek inSSIDer only to discover the unfortunate channel plan below.



My laptop, running OS X Mavericks, connected to Channel 9 with the stats listed below.



In seeing Channel 36 off all by its lonesome at a great signal strength, and without a bunch of other Access Points stomping all over it, there had to be a way to switch on over.

That's where the airport command comes in to play.  The airport command is located in the /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources directory in OSX Mavericks.

To get the available options for the airport command, navigate to the directory listed above and type './airport -h'.  Below are the available options:



To scan for the available networks, type './airport -s', from within the directory path listed above to see SSID, BSSID, RSSI, Channel, HT, Country Code and Security.  From the results listed below, you can see Channel 9 at -46 and Channel 36+1 at -56.  The better signal strength on Channel 9 (10 dB higher than Channel 36) is why the laptop joined Channel 9 versus Channel 36.



To switch on over to Channel 36, the following was performed using sudo in Terminal:
  1. Use the airport command to disassociate from the current Access Point
    • $ sudo ./airport -z
    • You will be disconnected from the WiFi Network as indicated by the WiFi Icon
  2. Use the airport command to set the desired channel, in my case 36:
    • $ sudo ./airport --channel=36
  3. Click on your WiFi Icon and select the desired SSID
NOTE: To enable the root user in OS X Mavericks, refer to the instructions in this Apple Support article.

You can confirm the WiFi channel, by pressing the OPTION/Alt key and clicking on the WiFi Icon.




Additionally, you could type './airport --getinfo' within the Terminal to list the current connection information.

Based on the connection information, you can see the results of changing to a lesser congested channel.

Other observations related to this change were the following:
  • Performing this action does not lock your WiFi card into the configured channel.  If the configured channel is not available, the normal scanning process will occur and your laptop will Associate to the WiFi network on another Channel.
  • When returning the location and the same Channel was still available, the laptop automatically connected back to the desired Channel.
  • If you do not connect back to the desired Channel, perform a scan to ensure the channel you think you are connecting to is still available.  For example, above Channel 36 was selected, however, in returning to the same location, Channel 36 was no longer available and changed to Channel 40.  The result was my WiFi connecting to a 2.4GHz Channel again due to the higher signal strength.  The commands listed above were re-run to connect to Channel 40.
To avoid having to type out that long directory name listed above, check out this article on creating aliases and adding them to your .profile file.

For additional information in adjusting network settings from the Terminal command line, check out this CNET article.