User`s guide

Chapter 6 Wireless Configuration

NWA3550 User’s Guide

You should activate ATC on the ZyXEL Device if your wireless network includes networking

devices that do not support WMM QoS, or if you want to prioritize traffic but do not want to

configure WMM QoS settings.

6.3.3 ATC+WMM

The ZyXEL Device can use a mapping mechanism to use both ATC and WMM QoS. The

ATC+WMM function prioritizes all packets transmitted onto the wireless network using

WMM QoS, and prioritizes all packets transmitted onto the wired network using ATC. See

Section 8.2.2 on page 118 for details of how to configure ATC+WMM.

Use the ATC+WMM function if you want to do the following:

• enable WMM QoS on your wireless network and automatically assign a WMM priority to

packets that do not already have one (see Section 6.3.3.1 on page 88).

• automatically prioritize all packets going from your wireless network to the wired network

(see Section 6.3.3.2 on page 88).

6.3.3.1 ATC+WMM from LAN to WLAN

ATC+WMM from LAN (the wired Local Area Network) to WLAN (the Wireless Local Area

Network) allows WMM prioritization of packets that do not already have WMM QoS

priorities assigned. The ZyXEL Device automatically classifies data packets using ATC and

then assigns WMM priorities based on that ATC classification.

The following table shows how priorities are assigned for packets coming from the LAN to the

WLAN.

6.3.3.2 ATC+WMM from WLAN to LAN

ATC+WMM from WLAN to LAN automatically prioritizes (assigns an ATC value to) all

packets coming from the WLAN. Packets are assigned an ATC value based on their WMM

value, not their size.

The following table shows how priorities are assigned for packets coming from the WLAN to

the LAN when using ATC+WMM.

Table 16 ATC + WMM Priority Assignment (LAN to WLAN)

PACKET SIZE (BYTES) ATC VALUE WMM VALUE

1 ~ 250 ATC_High WMM_VIDEO

250 ~ 1100 ATC_Medium WMM_BEST_EFFORT

1100 + ATC_Low WMM_BACKGROUND

Table 17 ATC + WMM Priority Assignment (WLAN to LAN)

WMM VALUE ATC VALUE

WMM_VOICE ATC_High

WMM_VIDEO ATC_High

WMM_BEST_EFFORT ATC_Medium

WMM_BACKGROUND ATC_Low

NONE ATC_Medium