The quality of WLAN service

This week our Special Focus takes a look at wireless LAN quality of service.

Our author (jcox@nww.com) says some wireless voice-over-IP (VoIP) vendors have created a simple, and proprietary, scheme to give some types of traffic, in this case voice, priority on a WLAN. That’s critical for voice because without it, the quality of the call erodes quickly.

An IEEE task group, 802.11e, is finalizing working on a QoS standard that will let nets set a range of priorities for different kinds of packets and, more importantly, control the time intervals between transmitted packets. The IEEE 802.11e task group is nearing the end of its work on a QoS standard for WLANs. It could gain final approval at the March 2004 IEEE plenary meeting, It’s this ability to schedule traffic flows that is critical in transforming WLANs from a best effort network to a guaranteed delivery environment.

The basic idea behind WLAN QoS is to handle traffic streams differently, based on what kind of packets they are, such as voice or data or video. Technically, class-of-service features categorize the traffic, and QoS features set the priorities for delivery.  QoS capability will also let net execs like manage WLAN bandwidth, which is a scarce resource that’s quickly consumed by voice and multi-media applications, or just big file transfers.

Some vendors, such as SpectraLink and Symbol Technologies, have introduced their own QoS features in the form of technique that lets their hardware products, both access points and client devices such as wireless VoIP phones, give voice traffic priority on the net. A number of WLAN equipment vendors, including Proxim and Trapeze Networks, have licensed the SpectraLink protocol to support wireless voice applications.

There other work being done too.  For more on this topic see: https://www.nwfusion.com/news/2003/1208specialfocus.html