Cisco AP541N Dual-band Single-radio Access Point Administration ...

4WirelessConfiguring Quality of Service (QoS)Table 24FieldQoS Parameters (Continued)DescriptionStation EDCA ParametersQueueAIFS(Inter-Frame Space)cwMin(MinimumContention Window)Queues are defined for different types of data transmittedfrom station-to-AP:Data 0 (Voice)—Highest priority queue, minimum delay.Time-sensitive data such as VoIP and streaming media areautomatically sent to this queue.Data 1(Video)—Highest priority queue, minimum delay.Time-sensitive video data is automatically sent to thisqueue.Data 2 (Best Effort)—Medium priority queue, mediumthroughput and delay. Most traditional IP data is sent to thisqueue.Data 3 (Background)—Lowest priority queue, highthroughput. Bulk data that requires maximum throughputand is not time-sensitive is sent to this queue (FTP data, forexample).The Arbitration Inter-Frame Spacing (AIFS) specifies await time for data frames. The wait time is measured inslots. Valid values for AIFS are 1 through 255.This parameter is used by the algorithm that determinesthe initial random wait time for data transmission during aperiod of contention for access point resources. The valuespecified here in the Minimum Contention Window is theupper limit from which the initial random backoff wait timewill be determined. The first random number generated willbe a number between 0 and the number specified here. Ifthe timer expires before the data frame is sent, a retrycounter is incremented and the random backoff value isdoubled. Doubling will continue until the size of the randombackoff value reaches the number defined in the MaximumContention Window.101 Cisco AP 541N Dual-band Single-radio Access Point Quick Start Guide