Chapter 6 Wireless LAN

 

 

 

 

 

 

 

TERM

DESCRIPTION

 

Roaming

If you have two or more NWAs (or other wireless access points) on your wireless

 

 

network, you can enable this option so that wireless devices can change locations

 

 

without having to log in again. This is useful for devices, such as notebooks, that

 

 

move around a lot.

 

 

 

 

Antenna

An antenna couples Radio Frequency (RF) signals onto air. A transmitter within a

 

 

wireless device sends an RF signal to the antenna, which propagates the signal

 

 

through the air. The antenna also operates in reverse by capturing RF signals from

 

 

the air.

 

 

Positioning the antennas properly increases the range and coverage area of a wireless

 

 

LAN.

 

 

 

6.10.2 WMM QoS

WMM (Wi-Fi MultiMedia) QoS (Quality of Service) ensures quality of service in wireless networks. It controls WLAN transmission priority on packets to be transmitted over the wireless network.

WMM QoS prioritizes wireless traffic according to the delivery requirements of the individual and applications. WMM QoS is a part of the IEEE 802.11e QoS enhancement to certified Wi-Fi wireless networks.

On APs without WMM QoS, all traffic streams are given the same access priority to the wireless network. If the introduction of another traffic stream creates a data transmission demand that exceeds the current network capacity, then the new traffic stream reduces the throughput of the other traffic streams.

The NWA uses WMM QoS to prioritize traffic streams according to the IEEE 802.1q or DSCP information in each packet’s header. The NWA automatically determines the priority to use for an individual traffic stream. This prevents reductions in data transmission for applications that are sensitive to latency and jitter (variations in delay).

6.10.2.1 WMM QoS Priorities

The following table describes the WMM QoS priority levels that the NWA uses.

Table 25 WMM QoS Priorities

Priority Level

description

 

 

voice

Typically used for traffic that is especially sensitive to jitter. Use this priority to

(WMM_VOICE)

reduce latency for improved voice quality.

 

 

 

video

Typically used for traffic which has some tolerance for jitter but needs to be

(WMM_VIDEO)

prioritized over other data traffic.

 

 

 

best effort

Typically used for traffic from applications or devices that lack QoS capabilities. Use

(WMM_BESTEFFORT)

best effort priority for traffic that is less sensitive to latency, but is affected by long

delays, such as Internet surfing.

 

 

 

background

This is typically used for non-critical traffic such as bulk transfers and print jobs

(WMM_BACKGROUND)

that are allowed but that should not affect other applications and users. Use

background priority for applications that do not have strict latency and throughput

 

 

requirements.

 

 

 

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NWA1000 Series User’s Guide