802.11g

802.11e

Sending a file over a network connection is a little like a Star Trek transporter system: You break the file down into a great many small packets of data, and transmit those packets individually to the other end of the connection. There, the packets are reassembled into the full file.

It doesn't matter what order the packets are sent in, nor that they arrive all at the same time or at the same rate or in the same order. It simply matters that they all arrive intact. If they're all present, the system can reassemble the packets into the complete file.

In sending other sorts of data over a network connection, things like the order that packets are sent and received and the rate at which they arrive do matter. Voice and streamed audio or video can be seriously distorted if packets turn up out of order, or if they 'bunch up' or 'space out' and do not arrive at a consistent rate. Nothing in the original 802.11 specification addressed what they call 'quality of service' (QoS) for data transmission, and that was the primary goal of IEEE task group 802.11e.

There are mechanisms for ensuring QoS in wired network, but for various arcane technical reasons these mechanisms cannot be used in 802.11 wireless networks. The 802.11e group is working on various enhancements to 802.11 to improve QoS, and the intent is that existing Wi-Fi gear will be able to take advantage of these improvements via firmware upgrades. The group is still working at this writing, with approval and publication not expected until sometime later in 2003.