Access Points

Reply
Occasional Contributor II
Posts: 31
Registered: ‎06-24-2009

Aruba AP125 configure for N

Hi folks! I am having a little bit of a dilemma! I installed a number AP125's in two buildings and configure these AP's 125 to operate in "N" mode. One of the issues is at a short distance away I connect to g-ht, but at transmission rate 11mbs. The antenna connectivity is in the 90% range if you run and rft test profile antenna-connectivity. Using netstumbler, I can see the SNR rate hover around 50-60dB, but every twenty seconds or so the signal drops off and comes back. I copied and pasted part of the configuration below since the entire config will be over the text limit. Any help or advice is welcomed......

Maintenance Mode Disabled Disabled ap system-profile "default"
Radio enable Enabled Enabled rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Mode ap-mode ap-mode rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
High throughput enable (radio) Enabled Enabled rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Channel 1+ N/A rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Beacon Period 100 msec 100 msec rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Transmit Power 30 dBm 30 dBm rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Advertise TPC Capability Enabled Enabled rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Spectrum load balancing Disabled Disabled rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Spectrum Load Balancing domain N/A N/A rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
RX Sensitivity Tuning Based Channel Reuse disable disable rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
RX Sensitivity Threshold 0 -dBm 0 -dBm rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Non 802.11 Interference Immunity Level-2 N/A rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Enable CSA Enabled Enabled rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
CSA Count 4 4 rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Management Frame Throttle interval 1 sec 1 sec rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Management Frame Throttle Limit 20 20 rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Protection for 802.11b Clients Enabled N/A rf dot11g-radio-profile "test-n" / rf dot11a-radio-profile "test-n"
Assignment single-band single-band rf arm-profile "test-n"
Allowed bands for 40MHz channels All All rf arm-profile "test-n"
Client Aware Enabled Enabled rf arm-profile "test-n"
Max Tx Power 30 dBm 30 dBm rf arm-profile "test-n"
Min Tx Power 15 dBm 15 dBm rf arm-profile "test-n"
Multi Band Scan Disabled Disabled rf arm-profile "test-n"
Rogue AP Aware Disabled Disabled rf arm-profile "test-n"
Scan Interval 10 sec 10 sec rf arm-profile "test-n"
Active Scan Disabled Disabled rf arm-profile "test-n"
Scanning Enabled Enabled rf arm-profile "test-n"
Scan Time 110 msec 110 msec rf arm-profile "test-n"
Power Save Aware Scan Disabled Disabled rf arm-profile "test-n"
Ideal Coverage Index 10 10 rf arm-profile "test-n"
Acceptable Coverage Index 4 4 rf arm-profile "test-n"
Free Channel Index 25 25 rf arm-profile "test-n"
Backoff Time 240 sec 240 sec rf arm-profile "test-n"
Error Rate Threshold 50 % 50 % rf arm-profile "test-n"
Error Rate Wait Time 30 sec 30 sec rf arm-profile "test-n"
Noise Threshold 75 -dBm 75 -dBm rf arm-profile "test-n"
Noise Wait Time 120 sec 120 sec rf arm-profile "test-n"
Minimum Scan Time 8 sec 8 sec rf arm-profile "test-n"
Load aware Scan Threshold 1250000 Bps 1250000 Bps rf arm-profile "test-n"
Mode Aware Arm Disabled Disabled rf arm-profile "test-n"
40 MHz intolerance Enabled Enabled rf ht-radio-profile "test-n"
Honor 40 MHz intolerance Enabled Enabled rf ht-radio-profile "test-n"
Legacy station workaround Enabled Enabled rf ht-radio-profile "test-n"
SSID enable Enabled Enabled wlan ssid-profile "test"
ESSID test test wlan ssid-profile "test"
Encryption wpa-aes wpa2-aes wpa-aes wpa2-aes wlan ssid-profile "test"
DTIM Interval 1 beacon periods 1 beacon periods wlan ssid-profile "test"
Basic Rates 1 2 11 12 24 48 54 6 12 24 54 wlan ssid-profile "test"
Transmit Rates 1 2 5 6 9 11 12 18 24 36 48 54 6 9 12 18 24 36 48 54 wlan ssid-profile "test"
Station Ageout Time 1000 sec 1000 sec wlan ssid-profile "test"
Max Transmit Attempts 8 8 wlan ssid-profile "test"
RTS Threshold 2333 bytes 2333 bytes wlan ssid-profile "test"
Short Preamble Enabled N/A wlan ssid-profile "test"
Max Associations 64 64 wlan ssid-profile "test"
Wireless Multimedia (WMM) Enabled Enabled wlan ssid-profile "test"
Wireless Multimedia U-APSD (WMM-UAPSD) Powersave Enabled Enabled wlan ssid-profile "test"
WMM TSPEC Min Inactivity Interval 0 msec 0 msec
Occasional Contributor II
Posts: 31
Registered: ‎06-24-2009

Aruba AP125 configure for N

This is one of the buildings and the secondary channel (g-HT) doesn't change even when the AP's see each other...

Jones.3.2 Jones Dorm 192.168.14.185 0 AP:HT:1+/17.5/33 0 AP:HT:44+/20/23 125 A 1m:42s
Jones.4.1 Jones Dorm 192.168.14.186 0 AP:HT:1+/20.5/33 0 AP:HT:157+/19/36 125 A 1m:7s
Jones.4.2 Jones Dorm 192.168.14.187 0 AP:HT:1+/20.5/33 0 AP:HT:36+/20/23 125 A 1m:43s
Jones.1.1 Jones Dorm 192.168.14.180 0 AP:HT:6-/20.5/33 0 AP:HT:36+/20/23 125 A 1m:23s
Jones.1.2 Jones Dorm 192.168.14.181 0 AP:HT:1+/20.5/33 0 AP:HT:157+/19/36 125 A 1m:43s
Jones.2.1 Jones Dorm 192.168.14.182 0 AP:HT:1+/20.5/33 0 AP:HT:48-/20/23 125 A 1m:23s
Jones.2.2 Jones Dorm 192.168.14.183 0 AP:HT:1+/20.5/33 0 AP:HT:149+/19/36 125 A 1m:44s
Jones.3.1 Jones Dorm 192.168.14.184 0 AP:HT:1+/20.5/33 0 AP:HT:153-/19/36 125 A 1m:8s
Guru Elite
Posts: 21,257
Registered: ‎03-29-2007

Allowed Channels for 40mhz operation

Your allowed bands for 40mhz operation in your ARM (Adaptive Radio Management profile) should be only A-only. If you are bonding channels together on 2.4ghz band, where there are only 3 non-overlapping channels, you are practically guaranteeing that you will see the type of interference where you can only transmit at lower rates due to collisions. You can still get very good performance if you are NOT bonding in the 2.4ghz spectrum.

Take it off.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 31
Registered: ‎06-24-2009

Allowed Channels for 40mhz operation

Many Thanks cjoseph!! I turned off g-HT and let arm do its thing overnight. The one thing that still puzzles me is that the AP channels for band g, or at least the majority are in channel 1. Most of these AP's are in ear shot of one another.... Is there a way to manually set the channel on the g band?


Jones.3.2 Jones Dorm 192.168.14.185 0
AP:6/20.5/33 0 AP:HT:44+/20/23 125 A
4m:56s
Jones.4.1 Jones Dorm 192.168.14.186 0
AP:6/20.5/33 0 AP:HT:157+/19/36 125 A
4m:36s
Jones.4.2 Jones Dorm 192.168.14.187 0
AP:1/20.5/33 0 AP:HT:36+/20/23 125 A
4m:57s
Jones.1.1 Jones Dorm 192.168.14.180 0
AP:1/20.5/33 0 AP:HT:36+/20/23 125 A
4m:21s
Jones.1.2 Jones Dorm 192.168.14.181 0
AP:1/20.5/33 0 AP:HT:157+/19/36 125 A
4m:58s
Jones.2.1 Jones Dorm 192.168.14.182 0
AP:1/20.5/33 0 AP:HT:48-/20/23 125 A
4m:21s
Jones.2.2 Jones Dorm 192.168.14.183 0
AP:1/20.5/33 0 AP:HT:149+/19/36 125 A
4m:56s
Jones.3.1 Jones Dorm 192.168.14.184 0
AP:1/20.5/33 0 AP:HT:153-/19/36 125 A
4m:36s
Guru Elite
Posts: 21,257
Registered: ‎03-29-2007

APS on different channels

Luca, that is most likely because there is congestion or interference on channel 11. There are only three choices and if there is a problem on channel 1, there are only two left and ARM has chosen the remaining two. You will not gain anything by manually overriding this. Are you still only able to associate at 11mb?


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

MVP
Posts: 501
Registered: ‎04-03-2007

Check ARM and see if it's making good decisions

If you are questioning why ARM has picked channel X instead of Y, investigate it:


  • Look at the AP's ARM RF summary


  • Sum up the numbers in the 'intf_idx' (Interference Index) column for the channel on which the AP is operating.
  • Do the same thing for another channel you feel could be a "better" option




  • Is the difference between the sums at or greater than the "Free Channel Index" configured in the profile? If not, then the AP is making a good decision.
  • If so, then you need to look into why the AP hasn't switched channels. Perhaps users on currently passing traffic and the AP is skipping any scanning and neglecting to change. You can watch the ARM scan times to see if it's skipping:





  • The worst thing that can happen is that you'll learn a lot more about how ARM works and is working. This is good, as blind trust almost always is a bad idea. :)

==========
Ryan Holland, ACDX #1 ACMX #1
The Ohio State University
Occasional Contributor II
Posts: 31
Registered: ‎06-24-2009

RF Summaries

Thanks Ryan!

Do you have an example of what is a good "intf_idx" vs. bad "intf_idx"? As I explorered ARM in several locations, there wasn't any consistency. The sums varied greatly.

Luca
Guru Elite
Posts: 21,257
Registered: ‎03-29-2007

Performance


Thanks Ryan!

Do you have an example of what is a good "intf_idx" vs. bad "intf_idx"? As I explorered ARM in several locations, there wasn't any consistency. The sums varied greatly.

Luca




Luca,

The most important thing is your performance. You do not have a great deal of choices for channels in the 2.4ghz band, and Aruba APs try to find the least congested channel with the fewest errors out of three (1,6,11), but sometimes there is very little choice. Aruba's ARM uses a statistical method to find the best channel and makes the adjustment just like Ryan says....constantly. If you statically configure those access points, every time there is a problem with performance, you will have to sample the environment and make changes times how many access points you have. Ultimately, you should only be concerned if you have performance issues..


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 31
Registered: ‎06-24-2009

Performance

I am experiencing some performance issues, but now believing it to be the concrete walls (6 - 8"s thick). There may be too much attenuation through the walls into the dorm rooms and with the AP's being in the hallways, ARM/RSSI, are making the adjustments to weak, because the AP's are in ear shot of each other.

Luca
Guru Elite
Posts: 21,257
Registered: ‎03-29-2007

Signal Strength

Luca,

The unwritten rule of thumb is that an access point will not penetrate more than one of those thick walls. Even if you can get signal into a common area in a dorm room it will not penetrate the second wall into a bedroom (everyone who deployed in these types of dorms, please chime in). Probably the best thing you can do is to deploy access points INSIDE the dorms and use the AP-120-WJ unit to protect them. You will then be able to place maybe a few APs outside the dorm rooms to provide minimal coverage. Attached is the AP-120-WJ protector for the AP125.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Search Airheads
Showing results for 
Search instead for 
Did you mean: