ZyXEL Communications PLA-450 - V3.60, Руководство пользователя

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Chapter 6 Wireless LAN
PLA450 User’s Guide
63
6.4.1 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 delivery requirements. 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 PLA450 uses WMM QoS to prioritize traffic streams according to the IEEE 802.1q tag or
DSCP information in each packet’s header. The PLA450 automatically determines the priority
to use for an individual traffic stream. This prevents reductions in data transmission for
applications that are sensitive to latency (delay) and jitter (variations in delay).
6.4.1.1 WMM QoS Priorities
The following table describes the WMM QoS priority levels that the PLA450 uses.
6.5 WPS Overview
WPS allows you to quickly set up a secure network with other WPS enabled devices, much
more easily than manually configuring wireless connections and security through a web
configurator.
Your PLA450 uses WPS to set up a secure connection with other WPS enabled wireless
devices in two ways. The first method uses a push-button, either physically located on the
housing of the wireless devices, or provided as a feature in the device’s software. See
Section
on page 27 for more information on using the WPS button on the PLA450. The second
method relies on the exchanging of PINs (Personal Identification Numbers) between wireless
devices. Both methods use the WPA(2) security standard, which uses a pre-shared key to
encrypt network traffic.
Table 11 WMM QoS Priorities
PRIORITY LEVEL DESCRIPTION
voice
(WMM_VOICE) Typically used for traffic that is especially sensitive to jitter. Use this priority
to reduce latency for improved voice quality.
video
(WMM_VIDEO) Typically used for traffic which has some tolerance for jitter but needs to be
prioritized over other data traffic.
best effort
(WMM_BEST_EFFORT) Typically used for traffic from applications or devices that lack QoS
capabilities. Use best effort priority for traffic that is less sensitive to latency,
but is affected by long delays, such as Internet surfing.
background
(WMM_BACKGROUND) This is typically used for non-critical traffic such as bulk transfers and print
jobs 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.