Technical Reference; Wmm Qos; Spanning Tree Protocol (Stp); Rapid Stp - ZyXEL Communications 802.11b/g Wireless Access Point NWA-1100 User Manual

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

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).
ZyXEL NWA-1100 User's Guide
Appendix E on page 153
Chapter 6 Wireless Settings Screen
for further readings on Wireless LAN.
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