Wireless Quality of Service

Wireless Quality of Service is essential for Wireless IP telephony. QoS guarantee priority of voice traffic over regular data traffic. QoS is essential for both type of IP telephony, wired and wireless.

Quality of Service is much more difficult to achieve on wireless then on wired networks. The reason for that is wireless shared medium. In this table you could compare differences in QoS for these 2 types of medium:

QoS characteristics for wired networks	QoS characteristics for wireless networks
User dedicated access (ethernet)	Shared access to bandwidth
Packets marked with 802.1p, IP TOS or DSCP	Packets marked with 802.1p, IP TOS or DSCP
QoS can be applied to upstream or downstream traffic	QoS can be applied to downstream traffic, and some devices on upstream
Full call admission control	Limited call admission control

802.1p provides mechanism for implementation of QoS on MAC layer (Layer 2). It is connected with VLANs (802.1q).
TOS is similar to 802.1p, but it is on Layer 3.
DSCP (Differentiated Services Code Point) use same field as TOS, but this 8 bit field is changed to have much more different markings.



If you are network professional my hot recommendation is book - Multimedia Wireless Networks: Technologies, Standards and Qos. It describes QoS in wireless networks for wireless multimedia applications.

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