This article is posted based on the recommendation suggested to one of customer in Macau. Even site specific environment should be considered ( for ex. country code ) and customized configuration need to be applied, but generally, same configuration recommended to other customer who are using Identifi solution with the version 9.21.
Recommendations for Wi-Fi Performance Improvements
1. Disable Legacy 802.11b support on 2.4GHz radios
Target: All Indoor APs
Remove 802.11b on 2.4GHz radio to avoid slowing down AP performance, as below
· Radio 1 configured only for 802.11a/n/ac for 5GHz
· Radio 2 configured only for 802.11g/n for 2.4GHz
2. Achieving High Throughput with 11n and 11ac Wireless APs
Target: All Indoor APs
a) Guard Interval
Short - Longer guard periods reduce the channel efficiency. 802.11n-compliant APs provide reduced guard periods, thereby increase the throughput.
b) Aggregate MPDUs
Enabled – Aggregate MPDU provides a significant improvement in throughput.
c) ADDBA Support
Enabled – ADDBA provides acknowledgement of a group of frames instead of a single frame. ADDBA Support must be enabled if Aggregate MPDU is enable.
d) LDPC
Enabled - LDPC increases the reliability of the transmission resulting in a 2dB increased performance compared to traditional 11n coding.
e) Min Basic Rate
6 Mbps - 2.4 GHz radio, 12 Mbps - 5 GHz radio
f) Protection Mode – Auto
g) Protection Type – CTS only
h) DTIM Period – 2
i) Beacon Period – 100
3. Manually create and configure a channel plan for the 5GHz and 2.4GHz bands
Target: All Indoor APs
perform radio assessment and assign available channels and transmission power based on “Macau”.
5GHz radios should all be configured to operate on different channels and care should be taken to avoid reusing the same channel as any adjacent 5GHz radios.
2.4GHz channels should be assigned to leverage existing RF obstructions so that some channel reuse may be possible.
4. Auto Channel Selection (ACS)
Target: All APs
ACS should be “disabled.
5. Configure Dynamic Channel Select to run in ‘Monitor’ mode and set the thresholds
Target: All APs
a) DCS Noise Threshold [dBm] = -82 (low noise environment)
b) DCS Channel Occupancy Threshold = 65
c) DCS Update Period [Minutes] = 2
Further explanation as below:
DCS Noise Threshold [dBm] = -60 (high noise environment, low performance)
DCS Channel Occupancy Threshold = 50
DCS Update Period [Minutes] = 5
-60 means more noise than -82
(eg. “Signal -30, noise -82” means better signal than “Signal -30, noise -60”)
· It's recommended to use DCS active mode after-hours or at a time where there are minimal devices / clients are on the network
· Best practice is to turn DCS mode to Off after AP's choose their channels
· From 9.21.05 the ability to set DCS to "none" was removed, the choice is now Monitor or Active mode
6. Auto Tx Power Ctrl ATPC
Target: All APs
ATPC = Disable
7. Enable Guest Wi-Fi to use 5GHz Radio
Target: All Indoor APs
Change Galalxy_Macau_WiFi to use 5GHz Radio (instead of just using 2.4GHz radio today) to improve data throughput for 5GHz capable end devices.
8. Radio Preference for Guest Connections to use 5 GHz
Target: All Indoor APs
Enable Band Steering to use 5 GHz for guest traffic.
Radio 1 (5GHz): 60 Strict Limit: No
Radio 2 (2.4GHz): 60 Strict Limit: No
For example, below settings is more aggressive to apply a 70/30 ratio by allowing 18 connections for 2.4GHz Load Balancing.
Radio 1 (5GHz): 60 Strict Limit: No
Radio 2 (2.4GHz): 18 Strict Limit: No
9. Change AP Properties “Country of Operations” and “Channel Plan”
Target: By Areas or APs on needed basis
Select the Country of operation within the specified Regulatory Domain for AP, this determines the available channel list and the maximum transmitting power for the country in which the AP is deployed.
Change from existing country “Taiwan” to “Macau” by individual area/APs, on needed basis, this increases 4 x 2.4GHz channels instead of 3 x 2.4GHz channels, however the Max. Tx power reduced from 20dbm to 15dbm.
AP Properties -> Country -> Macau
· By default the Tx power for Macau is 3dBm (2.4GHz) less than “Taiwan”, screen capture or record current power settings of all AP Profile(s), change country code to “Macau”.
· Review 2.4G "Radio2 attenuation" options to adjust/increase the Max Tx Power to maintain the same Tx power as before, or new setting according to Extreme’s recommendation.
- Radio Max. Tx power: 15 dBm (per Extreme AP country compliance setting for Macau)
Note: If Auto Tx Power Ctrl (ATPC) is disabled, the selected value or the largest value in the compliance table will be the power level used by the radio, whichever is smaller.
- Radio Min. Tx power: 3 dbm less than Max. Tx power. (default setting is “0”)
· Change country code setting will result in AP reboot.
Change 2.4GHz Radio 2 from existing 3 channel plan (1-6-11) to 4 channel plan (1-5-9-13) for Macau.
· 4 Channel Plan — ACS will scan 1, 5, 9, and 13 in most parts of the world including Macau.
10. Wireless QOS
Target: All Indoor APs
a) WMM
Enabled – for AP to accept WMM capable client associations, and will classify and prioritize the outbound traffic for all WMM clients. WMM clients will also classify and prioritize the inbound traffic, subset of 802.11e.
b) Turbo Voice
Disabled - traffic classified to be Voice (VO) AC and belongs to that VNS is transmitted by the AP via a queue called Turbo Voice (TVO) instead of the normal Voice (VO) queue. The TVO queue is tailored in terms of contention parameters and number of retries to maximize voice quality and voice capacity, for Legacy.
c) U-APSD
Disabled — Unscheduled Automatic Power Save Delivery feature works in conjunction with WMM and/or 802.11e, and it is automatically disabled if both WMM and 802.11e are disabled, for Legacy.
d) Flexible Client Access
Enabled & 100% Airtime – Air Time Fairless for high Speed devices over Legacy devices.
11. Optional - Force 5GHz capable device to select 5GHz Radio (Radio 1)
Target: For select area on needed basis or case by case.
Existing AP Properties are as below:
· Radio 1 configured for 802.11a/n/ac for 5GHz
· Radio 2 configured for 802.11g/n for 2.4GHz
802.11n is enabled on both radios 2.4GHz and 5GHz, to force 802.11n clients to choose 5GHz instead of 2.4GHz, remove 802.11n from Radio 2 such that all 5GHz capable end devices (802.11a/n/ac) will always select 5GHz Radio (hence forced) instead of connect to 2.4GHz radio.
12. Optional –Tuning Maximum Tx power for 2.4GHz and 5GHz Radio
Target: For select area on needed basis or case by case.
Other than radio settings for 2.4GHz and 5GHz devices for Radio 1 and Radio 2. Tweaking the power in some circumstances can also influence end devices to prefer and associate to radios operating in the 5GHz band.
Configure the 5GHz radios to Tx at the highest power levels permitted by the regulatory domain in use, and then configure the 2.4GHz radios to operate at 2 dBm less than the lowest 5GHz radios Tx power setting.
13. Dynamic Channel Selection (DCS)
DCS is typically not used or recommended for High Density areas. Areas that do leverage DCS may still require some manual intervention and these areas should be monitored to ensure that the operational channels in use are optimized.
This article details the DCS feature and includes some specific recommendations for leveraging DCS. Due to the dynamic and variable nature of the RF spectrums under consideration, as well as the different types of areas that the WiFi infrastructure covers, tuning the DCS attribute values will be required.
AP radios may change channels under the following circumstances:
- DCS is set to active and channel crosses the configured noise or utilization thresholds.
b) Radar is detected when operating on a DFS channel.
c) User selects another channel or manually triggers auto channel selection.
DCS allows a Wireless AP to monitor congestion and noise levels on the channel on which the Wireless AP is currently operating. DCS may be disabled or may be in one of two operational modes:
Monitor — When DCS is enabled in monitor mode and traffic or noise levels exceed the configured DCS thresholds, an alarm is triggered and an information log is generated. The
DCS monitor alarm is used for evaluating the RF environment of your deployed Wireless APs.
Periodic DCS alarms may be due to transient events and may not require any action. Persistent alarms from the same AP radios should trigger some manual action based on the threshold that is being crossed.
Active — When DCS is enabled in active mode and traffic or noise levels exceed the configured DCS thresholds, an alarm is triggered and an information log is generated. In addition, the Wireless AP ceases operating on the current channel and ACS is employed to select an alternate channel for the Wireless AP to operate on.
Note that it can take up to 30-seconds for ACS to determine the best, new channel.
DCS has three configurable options – two threshold values and an update period.
DCS Noise Threshold - value (in dBm) above which the AP will begin a search for another channel for this radio.
DCS Channel Occupancy Threshold - value (in %) that is synonymous with the channel congestion described previously. Above this value the AP will start to look for another channel for this radio.
DCS Update Period - time (range 1 to 5 minutes, default 5 minutes) between the AP evaluating the average noise and average congestion numbers to determine whether an action should be taken based upon the thresholds that have been defined.
DCS Channel Noise
As part of its fundamental operation, the AP measures the amount of ‘noise’ present on its operating channel. This is done separately for the 2.4 GHz and 5 GHz radios within the unit. Noise is a measure of signal created from the sum of all the interfering signal sources and unwanted signals within a measurement system. Noise value can vary substantially from one site/installation to the next.
DCS Channel Congestion
One of the most important measurements in DCS is that of channel congestion. Measured as a percent, this value is a quantity that expresses how much airtime on the current channel is occupied by 802.11 traffic originating and destined to OTHER AP-s or UNSUCCESSFUL communications. In other words how much air time is consumed by other AP-s and their clients, and by transmission collision.
DCS Deployment recommendations
Noise and congestion metrics will be unique to each site, and will even vary between areas. The best methodology for establishing the ‘best’ threshold values is to determine the normal or typical thresholds associated with a particular environment. However, this may not be simple or practical. In lieu of that approach suggested, starting threshold values would be:
Dynamic Channel Selection = Monitor
DCS Noise Threshold [dBm] = -82
DCS Channel Occupancy Threshold = 65
DCS Update Period [Minutes] = 2
Alarm logs should be reviewed to establish if specific areas normally and typically cross these thresholds, and values may be adjusted accordingly. While in Monitor Mode these values may also be modified or tuned to help establish baseline values without impacting the operational network.
Below recommendations are also from Extreme website.
1. Click AP tab At top of Controller GUI
2. Click Bulk Configuration tab in the Left column
3. Click AP Multi Edit Settings in the Left column
4. Select the desired AP Model in the center window, or manually highlight AP's holding Shift or CTRL key
5. Select "Active Mode" under each Dynamic Channel Sel.
Change "DCS Noise Threshold" to value of -60
Change "DCS Chl. Occupancy Th." to 50
Change "DCS Update Period [minutes]" to 5
6. Click Save to make the entry permanent
7. Allow the APs to negotiate the channels they wish to use (wait 10-15 minutes)
8. Perform second multi-edit and Select "OFF" under Dynamic Channel Sel. *see notes
9. Click Save to make the entry permanent
· It's best to use DCS active mode after-hours or at a time where there are minimal devices / clients are on the network
· Best practice is to turn DCS mode to Off after AP's choose their channels
· From 9.21.05 the ability to set DCS to "none" was removed, the choice is now Monitor or Active mode
14. 5GHz Channel List and Channel Planning
Channel Width
In general, very high density deployments or non-DFS deployments should use 20 MHz channels.
In lower density environments or environments where DFS channels can be used 40 MHz may be preferred.
In well designed DFS-friendly environments 80 MHz channels could be an option.
160 MHz channels are really not a viable option outside of SOHO deployments.
Channel Planning
Each AP should use a channel that is not used by any of its neighbor APs.
As a general rule, any AP whose coverage would overlap at a signal level of -85 dBm or higher.
Placing an AP near a neighboring AP that is on a directly adjacent channel should be avoided. In other words, a 36+ (40 MHz) channel should not be placed beside a 44+ channel. This is because the sidebands of adjacent channels at high transmit powers (or when placed very closely to each other) can cause interference. This can not always be avoided and will not always result in a performance impact, but is a good general practice to follow.
A Sample Channel Plan (based on US channels) is shown below
15. 2.4GHz 802.11b/g/n Channels
Channel Number
|
Lower Frequency
MHz
|
Center Frequency
MHz
|
Upper Frequency
MHz
|
1
|
2401
|
2412
|
2423
|
2
|
2404
|
2417
|
2428
|
3
|
2411
|
2422
|
2433
|
4
|
2416
|
2427
|
2438
|
5
|
2421
|
2432
|
2443
|
6
|
2426
|
2437
|
2448
|
7
|
2431
|
2442
|
2453
|
8
|
2436
|
2447
|
2458
|
9
|
2441
|
2452
|
2463
|
10
|
2451
|
2457
|
2468
|
11
|
2451
|
2462
|
2473
|
12
|
2456
|
2467
|
2478
|
13
|
2461
|
2472
|
2483
|
14
|
2473
|
2484
|
2495
|
16. 5GHz (802.11a/n/ac) Channels
Channel Number
|
Frequency MHz
|
Europe
(ETSI)
|
North America
(FCC)
|
36
|
5180
|
Indoors
|
✔
|
40
|
5200
|
Indoors
|
✔
|
44
|
5220
|
Indoors
|
✔
|
48
|
5240
|
Indoors
|
✔
|
52
|
5260
|
Indoors / DFS / TPC
|
DFS
|
56
|
5280
|
Indoors / DFS / TPC
|
DFS
|
60
|
5300
|
Indoors / DFS / TPC
|
DFS
|
64
|
5320
|
Indoors / DFS / TPC
|
DFS
|
100
|
5500
|
DFS / TPC
|
DFS
|
104
|
5520
|
DFS / TPC
|
DFS
|
108
|
5540
|
DFS / TPC
|
DFS
|
112
|
5560
|
DFS / TPC
|
DFS
|
116
|
5580
|
DFS / TPC
|
DFS
|
120
|
5600
|
DFS / TPC
|
No Access
|
124
|
5620
|
DFS / TPC
|
No Access
|
128
|
5640
|
DFS / TPC
|
No Access
|
132
|
5660
|
DFS / TPC
|
DFS
|
136
|
5680
|
DFS / TPC
|
DFS
|
140
|
5700
|
DFS / TPC
|
DFS
|
149
|
5745
|
SRD
|
✔
|
153
|
5765
|
SRD
|
✔
|
157
|
5785
|
SRD
|
✔
|
161
|
5805
|
SRD
|
✔
|
165
|
5825
|
SRD
|
✔
|
17. QOS
Extreme APs are capable of supporting 5 queues. The queues are implemented per radio.
Queue Name
|
Purpose
|
AC_VO
|
Voice
|
AC_VI
|
Video
|
AC_BK
|
Background
|
AC_BE
|
Best Effort
|
AC_TVO
|
Turbo Voice
|
Below recommendations are result from today’s meeting, please correct me if any concern:
1. Dynamic Channel Selection DCS: Monitor Mode (apply to all APs)
2. Auto Channel Selection ACS: Disable (apply to all APs)
3. Regulatory Country: Macau (change from existing country “Taiwan” to “Macau” by individual area/APs, on needed basis)
4. Auto Tx Power Ctrl ATPC: Disable (Apply to all APs)
5. Radio Max. Tx power: 15 dBm (per Extreme AP country compliance setting for Macau)
Note: If Auto Tx Power Ctrl (ATPC) is disabled, the selected value or the largest value in the compliance table will be the power level used by the radio, whichever is smaller.
6. Radio Min. Tx power: 3 dbm less than Max. Tx power. (default setting is “0”)
No comments:
Post a Comment