How Controller assign chnnaels to APs

Faisal Shabbir — Mon, 05 Jul 2021 10:36:43 GMT

Dear All,

could you please answer that how a Cisco controller assigns/decide different channels to more than one access point to avid any interference , suppose there are three APs on same location and how controller knows that all APs are on same location and how it will decide that all three will be assigned different 1,6 and 11 channels assuming that we are using 2.4GHZ

Read THIS.

Leo Laohoo — Tue, 21 Jul 2015 09:49:17 GMT

Read THIS.

i would appreciate if someone

Faisal Shabbir — Tue, 21 Jul 2015 10:15:32 GMT

i would appreciate if someone could answer me in few lines rather refering to a document Thanks

If someone has done the work

nathanielscriven — Tue, 21 Jul 2015 14:01:20 GMT

If someone has done the work of finding the document for you, the least you can do is say thank you then read it.

purpose of writing a post

Faisal Shabbir — Wed, 22 Jul 2015 04:33:23 GMT

purpose of writing a post here is to get the expert advise from professionals . googling a resource and sharing it here is not a big deal.

WLC examines a variety of

Venkatesh Attuluri — Wed, 22 Jul 2015 13:25:01 GMT

WLC examines a variety of real-time RF characteristics for channel assignments like Access point received energy,Noise,802.11 Interference,Utilization,Load,Signal Strength. If other wireless networks are present, the controller shifts the usage of channels to complement the other networks

As Leo mentioned read RRM.BUT

ajc — Fri, 24 Jul 2015 16:16:15 GMT

As Leo mentioned read RRM.

BUT, you need minimum 3 neighbour AP's so the RRM mechanism is actually applied by the WLC.

Two adjacent access points on

mohanak — Thu, 30 Jul 2015 10:12:32 GMT

Two adjacent access points on the same channel can cause either signal contention or signal collision. In a collision, data is not received by the access point. This functionality can become a problem, for example, when someone reading e-mail in a café affects the performance of the access point in a neighboring business. Even though these are completely separate networks, someone sending traffic to the café on channel 1 can disrupt communication in an enterprise using the same channel. Controllers can dynamically allocate access point channel assignments to avoid conflict and to increase capacity and performance. Channels are "reused" to avoid wasting scarce RF resources. In other words, channel 1 is allocated to a different access point far from the café, which is more effective than not using channel 1 altogether.

The controller's dynamic channel assignment (DCA) capabilities are also useful in minimizing adjacent channel interference between access points. For example, two overlapping channels in the 802.11b/g band, such as 1 and 2, cannot both simultaneously use 11/54 Mbps. By effectively reassigning channels, the controller keeps adjacent channels separated.

The controller examines a variety of real-time RF characteristics to efficiently handle channel assignments as follows:

•Access point received energy—The received signal strength measured between each access point and its nearby neighboring access points. Channels are optimized for the highest network capacity.

•Noise—Noise can limit signal quality at the client and access point. An increase in noise reduces the effective cell size and degrades user experience. By optimizing channels to avoid noise sources, the controller can optimize coverage while maintaining system capacity. If a channel is unusable due to excessive noise, that channel can be avoided.

•802.11 Interference—Interference is any 802.11 traffic that is not part of your wireless LAN, including rogue access points and neighboring wireless networks. Lightweight access points constantly scan all channels looking for sources of interference. If the amount of 802.11 interference exceeds a predefined configurable threshold (the default is 10 percent), the access point sends an alert to the controller. Using the RRM algorithms, the controller may then dynamically rearrange channel assignments to increase system performance in the presence of the interference. Such an adjustment could result in adjacent lightweight access points being on the same channel, but this setup is preferable to having the access points remain on a channel that is unusable due to an interfering foreign access point.

In addition, if other wireless networks are present, the controller shifts the usage of channels to complement the other networks. For example, if one network is on channel 6, an adjacent wireless LAN is assigned to channel 1 or 11. This arrangement increases the capacity of the network by limiting the sharing of frequencies. If a channel has virtually no capacity remaining, the controller may choose to avoid this channel. In very dense deployments in which all nonoverlapping channels are occupied, the controller does its best, but you must consider RF density when setting expectations.

•Utilization—When utilization monitoring is enabled, capacity calculations can consider that some access points are deployed in ways that carry more traffic than other access points (for example, a lobby versus an engineering area). The controller can then assign channels to improve the access point with the worst performance reported.

•Load—The load is taken into account when changing the channel structure to minimize the impact on clients currently in the wireless LAN. This metric keeps track of every access point's transmitted and received packet counts to determine how busy the access points are. New clients avoid an overloaded access point and associate to a new access point. This parameter is disabled by default.

The controller combines this RF characteristic information with RRM algorithms to make system-wide decisions. Conflicting demands are resolved using soft-decision metrics that guarantee the best choice for minimizing network interference. The end result is optimal channel configuration in a three-dimensional space, where access points on the floor above and below play a major factor in an overall wireless LAN configuration.

http://www.cisco.com/c/en/us/td/docs/wireless/controller/7-0/configuration/guide/c70/c70rrm.html#wp1104434

topic WLC examines a variety of in Wireless

How Controller assign chnnaels to APs

Read THIS.

i would appreciate if someone

If someone has done the work

purpose of writing a post

WLC examines a variety of

As Leo mentioned read RRM.BUT

Two adjacent access points on