AT-TQ2403 Management Software User's Guide

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Understanding Channel Management

When Channel Management is enabled, the AT-TQ2403 AP automatically assigns radio channels used by clustered access points to reduce mutual interference (or interference with other access points outside of its cluster). This maximizes Wi-Fi bandwidth and helps maintain the efficiency of communication over your wireless network.

(You must start channel management to get automatic channel assignments; it is disabled by default on a new AP. See “Stopping/Starting Automatic Channel Assignment”.)

How it Works in a Nutshell

At a specified interval (the default is 1 hour) or on demand (click Update), the Channel Manager maps APs to channel use and measures interference levels in the cluster. If significant channel interference is detected, the Channel Manager automatically re-assigns some or all of the APs to new channels per an efficiency algorithm (or automated channel plan).

For the Curious: More About Overlapping Channels

The radio frequency (RF) broadcast Channel defines the portion of the radio spectrum that the radio on the access point uses for transmitting and receiving. The range of available channels for an access point is determined by the IEEE 802.11 mode (also referred to as band) of the access point.

IEEE 802.11 b/g support consecutive channels (for example, U.S uses channels 1 through 11) inclusive, while IEEE 802.11a mode supports a larger set of non-consecutive channels.

Interference can occur when multiple access points within range of each other are broadcasting on the same or overlapping channels. The impact of this interference on network performance can intensify during busy times when a large amount of data and media traffic is competing for bandwidth.

The Channel Manager detects which bands (b/g or a) clustered APs are on, and uses a predetermined collection of channels that will not mutually interfere. For the "b/g" radio band, the classical set of non- interfering channels is 1, 6, and 11. Channels 1, 4, 8, 11 produce minimal overlap. A similar set of non-interfering channels is used for the "a" radio band, which includes all channels for that mode since they are not overlapping.

Example: A Network Before and After Channel Management

Without automated channel management, channel assignments to clustered APs might be made on consecutive channels, which would overlap and cause interference. For example, AP1 could be assigned to channel 6, AP2 to channel 6, and AP3 to channel 5 as shown in below figure. APs can broadcast on overlapping channels without automated channel management.

Figure 17: Before Channel Management Enable