Table of Contents

1 WLAN RRM Configuration· 1-1

Overview· 1-1

Configuration Task list 1-1

Configuring Data Transmission Rates· 1-2

Configuring 802.11a/802.11b/802.11g Rates· 1-2

Configuring 802.11n Rates· 1-2

Configuring Power Constraint 1-3

Prerequisites· 1-3

Configuring Power Constraint 1-3

Configuring Only Non-802.11h Channels to Be Scanned· 1-4

Configuring Only Non-802.11h Channels to Be Scanned· 1-4

Enabling 802.11g Protection· 1-4

Displaying and Maintaining WLAN RRM·· 1-4

 

 

This chapter includes these sections:

l          Overview

l          Configuring Data Transmission Rates

l          Configuring Power Constraint

l          Configuring Only Non-802.11h Channels to Be Scanned

l          Enabling 802.11g Protection

l          Displaying and Maintaining WLAN RRM

Overview

Radio signals are susceptible to surrounding interference. Causes of radio signal attenuation in different directions are very complex. Therefore, we need to make careful plans before deploying a WLAN network. After WLAN deployment, the running parameters still need to be adjusted because the radio environment is always varying due to interference from mobile obstacles, micro-wave ovens and so on. To adapt to environment changes, radio resources such as working channels and transmit power should be dynamically adjusted. Such adjustments are complex and require experienced personnel to implement regularly, which brings high maintenance costs.

WLAN radio resource management (RRM) is a scalable radio resource management solution. Through information collection (APs collect radio environment information in real time), information analysis (The AC analyzes the collected information), decision-making (The AC makes radio resource adjustment configuration according to analysis results), and implementation (APs implement the configuration made by the AC for radio resource optimization), WLAN RRM delivers a real-time, intelligent, integrated radio resource management solution, which enables a WLAN network to quickly adapt to radio environment changes and keep staying in a healthy state.

Configuration Task list

Complete the following tasks to configure WLAN RRM:

Task	Remarks
Configuring Data Transmission Rates	Optional
Configuring Power Constraint	Optional
Configuring Only Non-802.11h Channels to Be Scanned	Optional
Enabling 802.11g Protection	Optional

 

Configuring Data Transmission Rates

Configuring 802.11a/802.11b/802.11g Rates

Follow these steps to configure 802.11a/802.11b/802.11g rates:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter WLAN RRM view	wlan rrm	—
Configure rates (in Mbps) for 802.11a	dot11a { disabled-rate | mandatory-rate | supported-rate } rate-value	Optional By default, mandatory rates are 6, 12, and 24; supported rates are 9, 18, 36, 48, and 54; no rates are disabled.
Configure rates for 802.11b	dot11b { disabled-rate | mandatory-rate | supported-rate } rate-value	Optional By default, mandatory rates are 1 and 2; supported rates are 5.5 and 11; no rates are disabled.
Configure rates for 802.11g	dot11g { disabled-rate | mandatory-rate | supported-rate } rate-value	Optional By default, mandatory rates are 1, 2, 5.5 and 11; supported rates are 6, 9, 12, 18, 24, 36, 48 and 54; no rates are disabled.

 

Configuring 802.11n Rates

Configuration of mandatory and supported 802.11n rates is achieved by specifying the maximum Modulation and Coding Scheme (MCS) index. The MCS data rate table shows relations between data rates, MCS indexes, and parameters that affect data rates. A sample MCS data rate table is shown in Table 1-1. For the whole table, see IEEE P802.11n D2.00.

Table 1-1 MCS data rate table

MCS index	Modulation	Data rate (Mbps)
		800ns GI	400ns GI
0	BPSK	6.5	7.2
1	QPSK	13.0	14.4
2	QPSK	19.5	21.7
3	16-QAM	26.0	28.9

 

For example, if you specify the maximum MCS index as 5 for mandatory rates, rates corresponding to MCS indexes 0 through 5 are configured as 802.11n mandatory rates.

Mandatory rates must be supported by the AP and the clients that want to associate with the AP.

Supported rates allow some clients that support both mandatory and supported rates to choose higher rates when communicating with the AP.

Follow these steps to configure 802.11n rates:

To do…	Use the command…		Remarks
Enter system view		system-view	—
Enter RRM view		wlan rrm	—
Specify the maximum MCS index for 802.11n mandatory rates		dot11n mandatory maximum-mcs index	Optional No maximum MCS index is specified for 802.11n mandatory rates by default.
Specify the maximum MCS index for 802.11n supported rates		dot11n support maximum-mcs index	Optional By default, the maximum MCS index for 802.11n supported rates is 76.

 

 

Configuring Power Constraint

Prerequisites

The radio is enabled and at least one service template is configured.

Configuring Power Constraint

Follow these steps to configure power constraint:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter WLAN RRM view	wlan rrm	—
Enable spectrum management for 802.11a radios	spectrum-management enable	Required By default, spectrum management is disabled.
Configure power constraint for all 11a radios	power-constraint power-constraint	Optional The default value for power constraint is 0 dBm.

 

Configuring Only Non-802.11h Channels to Be Scanned

Configuring Only Non-802.11h Channels to Be Scanned

Follow these steps to configure only non-802.11h channels to be scanned:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter WLAN RRM view	wlan rrm	—
Configure only non-802.11h channels to be scanned	autochannel-set avoid-dot11h	Optional By default, the auto-channel set involves all channels.

 

Enabling 802.11g Protection

When both 802.11b and 802.11g clients access a WLAN network, interference easily occurs and thus access rate is greatly degraded because they adopt different modulation modes. To enable both 802.11b and 802.11g clients to operate normally, 802.11g protection needs to be enabled for an 802.11g device to send RTS/CTS or CTS-to-self packets to 802.11b devices, which will defer access to the medium.

Either of the following cases can start 802.11g protection on an 802.11g AP.

1)        An 802.11b client associates with the 802.11g AP. In this case, 802.11g protection is always enabled.

2)        The 802.11g AP detects an overlapping 802.11b BSS or some 802.11b packets that are not destined to it. For this case, you can use the following command to enable 802.11g protection or disable it using the undo form of the command.

Follow these steps to enable 802.11g protection:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enter WLAN RRM view	wlan rrm	—
Enable 802.11g protection	dot11g protection enable	Optional Disabled by default.

 

 

Displaying and Maintaining WLAN RRM

To do…	Use the command…	Remarks
Display WLAN RRM configuration information	display wlan rrm	Available in any view