WIFI性能测试一 --- wifi的ATF功能

WIFI性能测试一 --- wifi的ATF功能

最近解决公司wifi产品经常断线和连接不稳定时，查阅了一些资料，现总结记录如下：

1. wifi的ATF功能

参考链接： http://www.wificert.org/air-time-fairness/

文中已cisco的路由器进行了配置简介，详情请看连接。

Some days ago, I had the opportunity to play with a beta release (8.1.1.80) It’s a beta for the coming 8.1 MR1 release (planned Aug. 2015). The software was installed on a 5508 controller.

In this release, a new feature is brought into the Wireless game for QoS (on the Wireless side). The method is called Air Time Fairness (ATF).

With wireless networking, the transmission medium is via radio waves that transmit data at varying rates. Instead of regulating egress bandwidth, it could makes more sense to regulate the amount of airtime needed to transmit frames. Air Time Fairness (ATF) is a form of wireless QoS that regulates downlink airtime. (Note. only Downlink)

Before a frame is transmitted, the ATF budget for that SSID is checked to ensure that there is sufficient airtime budget to transmit the frame. Each SSID can be thought of as having a token (1 token = 1 microsecond of airtime). If the token bucket contains enough airtime to transmit the frame, it is transmitted. Otherwise, the frame can either be dropped or deferred. Deferring a frame means that the frame is not admitted into the Access Category Queue (ACQ). Instead, it remains in the Client Priority Queue (CPQ) and may be transmitted at a later time.

understand how it works.

Nice to know:

•     ATF takes place on the access points. The wireless controller is used simply to configure the feature and display results.
•     ATF policies are applied only in the downlink direction (AP to client).
•     ATF policies are applied only on wireless data frames
•     ATF is configured per-SSID, each SSID is granted equal airtime.
•     ATF can be enabled/disabled on an individual AP
•     ATF will be supported on the 1700,2700,3700,3600,3500,1260,2600,1570 AP
•     ATF will work on AP in local and FlexConnect mode.
•     ATF will be configured to either drop or defer frames that exceed airtime policies.
•     If the frame is deferred, it will be buffered and transmit at some point in the future when the offending SSID has a sufficient airtime budget. Of course, there is a limit as to how many frames can be buffered. If this limit is crossed, frames will be dropped regardless.
•     ATF can be globally enabled/disabled

更新中……