QoS

• WFA Defaults — Populates the WAP device and the Station EDCA parameters with Wi-Fi Alliance default values, which are best for general, mixed traffic.

• Optimized For Voice — Populates the WAP device and the Station EDCA parameters with values that are best for voice traffic.

• Custom — Enables you to choose custom EDCA parameters.

These four queues are defined for different types of data transmitted from WAP- to-station. If you choose a Custom template, the parameters that define the queues are configurable; otherwise, they are set to predefined values appropriate to your selection. The four queues are:

• Data 0 (Voice) — High priority queue, with minimum delay. Time-sensitive data such as VoIP and streaming media are automatically sent to this queue.

• Data 1 (Video) — High priority queue, with minimum delay. Time-sensitive video data is automatically sent to this queue.

• Data 2 (Best Effort) — Medium priority queue, with medium throughput and delay. Most traditional IP data is sent to this queue.

• Data 3 (Background) — Lowest priority queue, with high throughput. Bulk data that requires maximum throughput and is not time-sensitive is sent to this queue (FTP data, for example).

Wi-Fi MultiMedia (WMM)— This field is enabled by default. With WMM enabled, QoS prioritization and coordination of wireless medium access is on. With WMM enabled, QoS settings on the WAP device control downstream traffic flowing from the WAP device to client station (AP EDCA parameters) and the upstream traffic flowing from the station to the AP (station EDCA parameters).

Disabling WMM deactivates QoS control of station EDCA parameters on upstream traffic flowing from the station to the WAP device. With WMM disabled, you can still set some parameters on the downstream traffic flowing from the WAP device to the client station (AP EDCA parameters).

• Arbitration Inter-Frame Space (AIFS) — Wait time for the data frames. The wait time is measured in slots. Valid values for AIFS are 1 through 255.

• Minimum Contention Window — An input to the algorithm that determines the initial random backoff wait time (window) for a retry of a transmission failure.

  This value is the upper limit (in milliseconds) of a range from which the initial random backoff wait time is determined. The first random number generated is a number between 0 and the number specified here. If the first random backoff wait time expires before the data frame is sent, a retry counter is incremented and the random backoff value (window) is doubled. Doubling continues until the size of the random backoff value reaches the number defined in the Maximum Contention Window.

  Valid values are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1023. This value must be lower than the value for the Maximum Contention Window.

• Maximum Contention Window — The upper limit in milliseconds for the doubling of the random backoff value. This doubling continues until either the data frame is sent or the Maximum Contention Window size is reached.

  After the Maximum Contention Window size is reached, retries continue until a maximum number of retries allowed is reached.

  Valid values are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1023. This value must be higher than the value for the Minimum Contention Window.

• Maximum Burst — A WAP EDCA parameter that applies only to traffic flowing from the WAP to the client station.

  This value specifies (in milliseconds) the maximum burst length allowed for packet bursts on the wireless network. A packet burst is a collection of multiple frames transmitted without header information. The decreased overhead results in higher throughput and better performance. Valid values are 0.0 through 999.

• TXOP Limit (Station only) — The TXOP Limit is a station EDCA parameter that only applies to traffic flowing from the client station to the WAP device. The Transmission Opportunity (TXOP) is an interval of time, in milliseconds, when a WME client station has the right to initiate transmissions onto the wireless medium (WM) towards the WAP device. The TXOP Limit maximum value is 65535.

• No Acknowledgment — Check Enable to specify that the WAP device should not acknowledge frames with QosNoAck as the service class value.

• Unscheduled Automatic Power Save Delivery (APSD) — Check Enable to enable APSD. The APSD is recommended if VoIP phones access the network through the WAP device.