ZyXEL Communications NWA-1100 User Manual

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 Chapter 6 Wireless Settings Screen
ZyXEL NWA-1100 User’s Guide
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See the tables describing the fields in the Access Point and Bridge operating modes for 
descriptions of the fields in this screen.
6.5  Technical Reference
This section provides technical background information about the topics covered in this 
chapter. Refer to 
 for further readings on Wireless LAN.
6.5.1  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 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 ZyXEL Device uses WMM QoS to prioritize traffic streams according to the IEEE 802.1q 
or DSCP information in each packet’s header. The ZyXEL Device 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).
6.5.2  Spanning Tree Protocol (STP)
STP detects and breaks network loops and provides backup links between switches, bridges or 
routers. It allows a bridge to interact with other STP-compliant bridges in your network to 
ensure that only one route exists between any two stations on the network.
6.5.2.1  Rapid STP
The ZyXEL Device uses IEEE 802.1w RSTP (Rapid Spanning Tree Protocol) that allow faster 
convergence of the spanning tree (while also being backwards compatible with STP-only 
aware bridges). Using RSTP topology change information does not have to propagate to the 
root bridge and unwanted learned addresses are flushed from the filtering database. In RSTP, 
the port states are Discarding, Learning, and Forwarding.
6.5.2.2  STP Terminology
The root bridge is the base of the spanning tree; it is the bridge with the lowest identifier value 
(MAC address).