Wireless Quality of Service

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

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

So from the table above, you can see differences in applying a QoS between wired and wireless networks. Both of them have the same marking procedure with 802.1p or dedicated 3 bits for QoS on MAC Layer in IP packet. There is also even more used a QoS mechanism called IP TOS (Type of Service) or DSCP with 6 bits differentiated service code point (DSCP) and 2 bits Explicit Congestion Notification field. For wired networks QoS can be applied on both upstream and downstream traffic. On wireless networks QoS can be applied for downstream traffic, but in upstream direction only on some devices.

Call admission control is a preventive Congestion Control Procedure which ensures sufficient bandwidth for some specified types of data like voice and video. On wired networks you can have full admission control, while on wireless you have only limited options.

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