Setting Up Overlapping Signals to Ensure Continuous Connectivity With Rf Scanning Devices
Radio Resource Management
Information About Radio Resource Management
The Radio Resource Management (RRM) software that is embedded in the device acts as a built-in Radio Frequency (RF) engineer to consistently provide real-time RF management of your wireless network. RRM enables devices to continually monitor their associated lightweight access points for the following information:
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Traffic load—The total bandwidth used for transmitting and receiving traffic. It enables wireless LAN managers to track and plan network growth ahead of client demand.
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Interference—The amount of traffic coming from other 802.11 sources.
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Noise—The amount of non-802.11 traffic that is interfering with the currently assigned channel.
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Coverage—The Received Signal Strength (RSSI) and signal-to-noise ratio (SNR) for all connected clients.
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Other —The number of nearby access points.
RRM performs these functions:
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Radio resource monitoring
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Power control transmission
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Dynamic channel assignment
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Coverage hole detection and correction
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RF grouping
Note | RRM grouping does not occur when an AP operates in a static channel that is not in the DCA channel list. The Neighbor Discovery Protocol (NDP) is sent only on DCA channels; therefore, when a radio operates on a non-DCA channel, it does not receive NDP on the channel. |
Radio Resource Monitoring
RRM automatically detects and configures new devices and lightweight access points as they are added to the network. It then automatically adjusts the associated and nearby lightweight access points to optimize coverage and capacity.
Lightweight access points can scan all the valid channels for the country of operation as well as for channels available in other locations. The access points in local mode go offchannel for a period not greater than 70 ms to monitor these channels for noise and interference. Packets collected during this time are analyzed to detect rogue access points, rogue clients, ad-hoc clients, and interfering access points.
Note | In the presence of voice traffic or other critical traffic (in the last 100 ms), access points can defer off-channel measurements. The access points also defer off-channel measurements based on the WLAN scan priority configurations. |
Each access point spends only 0.2 percent of its time off channel. This activity is distributed across all the access points so that adjacent access points are not scanning at the same time, which could adversely affect wireless LAN performance.
Information About RF Groups
An RF group is a logical collection of controllers that coordinate to perform RRM in a globally optimized manner to perform network calculations on a per-radio basis. Separate RF groups exist for 2.4-GHz and 5-GHz networks. Clustering Cisco Catalyst 9800 Series Wireless Controller into a single RF group enables the RRM algorithms to scale beyond the capabilities of a single Cisco Catalyst 9800 Series Wireless Controller .
An RF group is created based on the following parameters:
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User-configured RF network name.
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Neighbor discovery performed at the radio level.
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Country list configured on the controller.
RF grouping runs between controllers .
Lightweight access points periodically send out neighbor messages over the air. Access points using the same RF group name validate messages from each other.
When access points on different controllers hear validated neighbor messages at a signal strength of –80 dBm or stronger, the controllers dynamically form an RF neighborhood in auto mode. In static mode, the leader is manually selected and the members are added to the RF Group.
Note | RF groups and mobility groups are similar, in that, they both define clusters of controllers , but they are different in terms of their use. An RF group facilitates scalable, system-wide dynamic RF management, while a mobility group facilitates scalable, system-wide mobility and controller redundancy. |
RF Group Leader
RF Group Leader can be configured in two ways as follows:
Note | RF Group Leader is chosen on the basis of the controller with the greatest AP capacity (platform limit.) If multiple controllers have the same capacity, the leader is the one with the highest management IP address. |
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Auto Mode: In this mode, the members of an RF group elect an RF group leader to maintain a primary power and channel scheme for the group. The RF grouping algorithm dynamically chooses the RF group leader and ensures that an RF group leader is always present. Group leader assignments can and do change (for instance, if the current RF group leader becomes inoperable or RF group members experience major changes).
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Static Mode: In this mode, a user selects a controller as an RF group leader manually. In this mode, the leader and the members are manually configured and fixed. If the members are unable to join the RF group, the reason is indicated. The leader tries to establish a connection with a member every minute if the member has not joined in the previous attempt.
The RF group leader analyzes real-time radio data collected by the system, calculates the power and channel assignments, and sends them to each of the controllers in the RF group. The RRM algorithms ensure system-wide stability, and restrain channel and power scheme changes to the appropriate local RF neighborhoods.
Note | When a controller becomes both leader and member for a specific radio, you get to view the IPv4 and IPv6 address as part of the group leader. When a Controller A becomes a member and Controller B becomes a leader, the Controller A displays either IPv4 or IPv6 address of Controller B using the address it is connected. So, if both leader and member are not the same, you get to view only one IPv4 or IPv6 address as a group leader in the member. |
If Dynamic Channel Assignment (DCA) needs to use the worst-performing radio as the single criterion for adopting a new channel plan, it can result in pinning or cascading problems.
The main cause of both pinning and cascading is that any potential channel plan changes are controlled by the RF circumstances of the worst-performing radio. The DCA algorithm does not do this; instead, it does the following:
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Multiple local searches: The DCA search algorithm performs multiple local searches initiated by different radios in the same DCA run rather than performing a single global search that is driven by a single radio. This change addresses both pinning and cascading, while maintaining the desired flexibility and adaptability of DCA and without jeopardizing stability.
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Multiple Channel Plan Change Initiators (CPCIs): Previously, the single worst radio was the sole initiator of a channel plan change. Now each radio in an RF group is evaluated and prioritized as a potential initiator. Intelligent randomization of the resulting list ensures that every radio is eventually evaluated, which eliminates the potential for pinning.
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Limiting the propagation of channel plan changes (Localization): For each CPCI radio, the DCA algorithm performs a local search for a better channel plan, but only the CPCI radio itself and its one-hop neighboring access points are actually allowed to change their current transmit channels. The impact of an access point triggering a channel plan change is felt only to within two RF hops from that access point, and the actual channel plan changes are confined to within a one-hop RF neighborhood. Because this limitation applies across all CPCI radios, cascading cannot occur.
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Non-RSSI-based cumulative cost metric: A cumulative cost metric measures how well an entire region, neighborhood, or network performs with respect to a given channel plan. The individual cost metrics of all the access points in that area are considered in order to provide an overall understanding of the channel plan's quality. These metrics ensure that the improvement or deterioration of each single radio is factored into any channel plan change. The objective is to prevent channel plan changes in which a single radio improves, but at the expense of multiple other radios experiencing a considerable performance decline.
The RRM algorithms run at a specified updated interval, which is 600 seconds by default. Between update intervals, the RF group leader sends keepalive messages to each of the RF group members and collects real-time RF data.
Note | Several monitoring intervals are also available. See the Configuring RRM section for details. |
RF Grouping Failure Reason Codes
RF Grouping failure reason codes and their explanations are listed below:
| Reason Code | Description |
|---|---|
| 1 | Maximum number (20) of controllers are already present in the group. |
| 2 | If the following conditions are met:
|
| 3 | Group ID do not match. |
| 4 | Request does not include source type. |
| 5 | Group spilt message to all member while group is being reformed. |
| 6 | Auto leader is joining a static leader, during the process deletes all the members. |
| 9 | Grouping mode is turned off. |
| 11 | Country code does not match. |
| 12 | Controller is up in hierarchy compared to sender of join command (static mode). Requestor is up in hierarchy (auto mode). |
| 13 | Controller is configured as static leader and receives join request from another static leader. |
| 14 | Controller is already a member of static group and receives a join request from another static leader. |
| 15 | Controller is a static leader and receives join request from non-static member. |
| 16 | Join request is not intended to the controller. Controller name and IP do not match. |
| 18 | RF domain do not match. |
| 19 | Controller received a Hello packet at incorrect state. |
| 20 | Controller has already joined Auto leader, now gets a join request from static leader. |
| 21 | Group mode change. Domain name change from CLI. Static member is removed from CLI. |
| 22 | Max switch size (350) is reached |
Additional Reference
Radio Resource Management White Paper: https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_RRM_White_Paper/b_RRM_White_Paper_chapter_011.html
RF Group Name
A controller is configured in an RF group name, which is sent to all the access points joined to the controller and used by the access points as the shared secret for generating the hashed MIC in the neighbor messages. To create an RF group, you configure all of the controllers to be included in the group with the same RF group name.
If there is any possibility that an access point joined to a controller might hear RF transmissions from an access point on a different controller , you should configure the controller with the same RF group name. If RF transmissions between access points can be heard, then system-wide RRM is recommended to avoid 802.11 interference and contention as much as possible.
Secure RF Groups
Secure RF groups enable to encrypt and secure RF grouping and RRM message exchanges over DTLS tunnel. During the DTLS handshake controllers authenticate each other with wireless management trust-point certificate.
Note | If a controller has to be part of secure RF-group, that controller must be part of the same mobility group. |
Transmit Power Control
The device dynamically controls access point transmit power based on the real-time wireless LAN conditions.
The Transmit Power Control (TPC) algorithm increases and decreases an access point's power in response to changes in the RF environment. In most instances, TPC seeks to lower an access point's power to reduce interference, but in the case of a sudden change in the RF coverage, for example, if an access point fails or becomes disabled, TPC can also increase power on the surrounding access points. This feature is different from coverage hole detection, which is primarily concerned with clients. TPC provides enough RF power to achieve the required coverage levels while avoiding channel interference between access points. We recommend that you select TPCv1; TPCv2 option is deprecated. With TPCv1, you can select the channel aware mode; we recommend that you select this option for 5 GHz, and leave it unchecked for 2.4 GHz.
Overriding the TPC Algorithm with Minimum and Maximum Transmit Power Settings
The TPC algorithm balances RF power in many diverse RF environments. However, it is possible that automatic power control will not be able to resolve some scenarios in which an adequate RF design was not possible to implement due to architectural restrictions or site restrictions, for example, when all the access points must be mounted in a central hallway, placing the access points close together, but requiring coverage to the edge of the building.
In these scenarios, you can configure maximum and minimum transmit power limits to override TPC recommendations. The maximum and minimum TPC power settings apply to all the access points through RF profiles in a RF network.
To set the Maximum Power Level Assignment and Minimum Power Level Assignment, enter the maximum and minimum transmit power used by RRM in the fields in the Tx Power Control window. The range for these parameters is -10 to 30 dBm. The minimum value cannot be greater than the maximum value; the maximum value cannot be less than the minimum value.
If you configure a maximum transmit power, RRM does not allow any access point attached to the controller, to exceed this transmit power level (whether the power is set by RRM TPC or by coverage hole detection). For example, if you configure a maximum transmit power of 11 dBm, no access point will transmit above 11 dBm, unless the access point is configured manually.
Cisco APs support power level changes in 3 dB granularity. TPC Min and Max power settings allow for values in 1 dB increments. The resulting power level will be rounded to the nearest value supported in the allowed powers entry for the AP model and the current serving channel.
Each AP model has its own set of power levels localized for its regulatory country and region. Moreover, the power levels for the same AP model will vary based on the band and channel it is set to. For more information on Allowed Power Level vs. Actual power(in dBm), use the show ap name <name> config slot <0|1|2|3> command to view the specific number of power levels, the range of power levels allowed, and the current power level setting on the AP.
Dynamic Channel Assignment
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 an e-mail in a café affects the performance of the access point in a neighboring business. Even though these are separate networks, someone sending traffic to the café on channel 1 can disrupt communication in an enterprise using the same channel. Devices can dynamically allocate access point channel assignments to avoid conflict and 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 device '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 simultaneously use 11 or 54 Mbps. By effectively reassigning channels, the device keeps adjacent channels that are separated.
Note | We recommend that you use only nonoverlapping channels (1, 6, 11, and so on). |
Note | Channel change does not require you to shut down the radio. |
The device examines a variety of real-time RF characteristics to efficiently handle channel assignments as follows:
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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.
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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 device can optimize coverage while maintaining system capacity. If a channel is unusable due to excessive noise, that channel can be avoided.
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802.11 interference: Interference is any 802.11 traffic that is not a part of your wireless LAN, including rogue access points and neighboring wireless networks. Lightweight access points constantly scan all the 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 device . Using the RRM algorithms, the device 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 device 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 device may choose to avoid this channel. In huge deployments in which all nonoverlapping channels are occupied, the device does its best, but you must consider RF density when setting expectations.
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Load and 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 device can then assign channels to improve the access point that has performed the worst. The load is taken into account when changing the channel structure to minimize the impact on the clients that are 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 Load and utilization parameter is disabled by default.
The device 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.
Note | DCA supports only 20-MHz channels in 2.4-GHz band. |
Note | In a Dynamic Frequency Selection (DFS) enabled AP environment, ensure that you enable the UNII2 channels option under the DCA channel to allow 100-MHz separation for the dual 5-GHz radios. |
The RRM startup mode is invoked in the following conditions:
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In a single- device environment, the RRM startup mode is invoked after the device is upgraded and rebooted.
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In a multiple- device environment, the RRM startup mode is invoked after an RF Group leader is elected.
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You can trigger the RRM startup mode from the CLI.
The RRM startup mode runs for 100 minutes (10 iterations at 10-minute intervals). The duration of the RRM startup mode is independent of the DCA interval, sensitivity, and network size. The startup mode consists of 10 DCA runs with high sensitivity (making channel changes easy and sensitive to the environment) to converge to a steady-state channel plan. After the startup mode is finished, DCA continues to run at the specified interval and sensitivity.
Note | DCA algorithm interval is set to 1 hour, but DCA algorithm always runs in default interval of 10 min, channel allocation occurs at 10-min intervals for the first 10 cycles, and channel changes occur as per the DCA algorithm every 10 min. After that the DCA algorithm goes back to the configured time interval. This is common for both DCA interval and anchor time because it follows the steady state. |
Note | If Dynamic Channel Assignment (DCA)/Transmit Power Control (TPC) is turned off on the RF group member, and auto is set on RF group leader, the channel or TX power on a member gets changed as per the algorithm that is run on the RF group leader. |
Dynamic Bandwidth Selection
While upgrading from 11n to 11ac, the Dynamic Bandwidth Selection (DBS) algorithm provides a smooth transition for various configurations.
The following pointers describe the functionalities of DBS:
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It applies an additional layer of bias on top of those applied to the core DCA, for channel assignment in order to maximize the network throughput by dynamically varying the channel width.
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It fine tunes the channel allocations by constantly monitoring the channel and Base Station Subsystem (BSS) statistics.
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It evaluates the transient parameters, such as 11n or 11ac client mix, load, and traffic flow types.
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It reacts to the fast-changing statistics by varying the BSS channel width or adapting to the unique and new channel orientations through 11ac for selection between 40 MHz and 80 MHz bandwidths.
Coverage Hole Detection and Correction
The RRM coverage hole detection algorithm can detect areas of radio coverage in a wireless LAN that are below the level needed for robust radio performance. This feature can alert you to the need for an additional (or relocated) lightweight access point.
If clients on a lightweight access point are detected at threshold levels (RSSI, failed client count, percentage of failed packets, and number of failed packets) lower than those specified in the RRM configuration, the access point sends a "coverage hole" alert to the device . The alert indicates the existence of an area where clients are continually experiencing poor signal coverage, without having a viable access point to which to roam. The device discriminates between coverage holes that can and cannot be corrected. For coverage holes that can be corrected, the device mitigates the coverage hole by increasing the transmit power level for that specific access point. The device does not mitigate coverage holes caused by clients that are unable to increase their transmit power or are statically set to a power level because increasing their downstream transmit power might increase interference in the network.
Restrictions for Radio Resource Management
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The number of APs in a RF-group is limited to 3000.
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If an AP tries to join the RF-group that already holds the maximum number of APs it can support, the device rejects the application and throws an error.
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Disabling all data rates for default rf-profile or custom rf-profile, impacts ISSU upgrade and client join process after the software upgrade (ISSU or non-ISSU). To prevent this, you must enable at least one data rate (for example, ap dot11 24 rate RATE_5_5M enable) on the default rf-profile or custom rf-profile. We recommend that you enable the lowest data rate if efficiency is of prime concern.
How to Configure RRM
Configuring Neighbor Discovery Type (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | On the Radio Resource Management page, click either the 5 GHz Band or the 2.4 GHz Band tab. |
| Step 3 | In the General tab under Noise/Interference/Rogue/CleanAir# Monitoring Channels, choose either Transparent or Protected from the RRM Neighbor Discover Type drop-down list. |
| Step 4 | Click Apply to save your configuration. |
Configuring Neighbor Discovery Type (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm ndp-type {protected | transparent} Example: | Configures the neighbor discovery type. By default, the mode is set to "transparent".
|
| Step 3 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring RF Groups
This section describes how to configure RF groups through either the GUI or the CLI.
Note | When the multiple-country feature is being used, all controllers intended to join the same RF group must be configured with the same set of countries, configured in the same order. |
Note | In Auto mode , RF group leader will skip TPC and DCA for first three runs of grouping cycle in order to stabilize the RF-group |
Configuring RF Group Selection Mode (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | On the RRM page, click the relevant band's tab: either 5 GHz Band or 2.4 GHz Band. |
| Step 3 | Click the RF Grouping tab. |
| Step 4 | Choose the appropriate Group Mode from these options:
|
| Step 5 | Save the configuration. |
Configuring RF Group Selection Mode (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm group-mode{auto | leader | off} Example: | Configures RF group selection mode for 802.11 bands.
|
| Step 3 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring an RF Group Name (CLI)
Procedure
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. | ||
| Step 2 | wireless rf-network name Example: | Creates an RF group. The group name should be ASCII String up to 19 characters and is case sensitive.
| ||
| Step 3 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring Members in an 802.11 Static RF Group (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | On the RRM page, click either the 5 GHz Band or 2.4 GHz Band tab. |
| Step 3 | Click the RF Grouping tab. |
| Step 4 | Choose the appropriate Group Mode from the following options:
|
| Step 5 | Under Group Members section, click Add. |
| Step 6 | In the Add Static Member window that is displayed, enter the controller name and the IPv4 or IPv6 address of the controller. |
| Step 7 | Click Save & Apply to Device. |
Configuring Members in an 802.11 Static RF Group (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm group-member group_name ip_addr Example: | Configures members in a 802.11 static RF group. The group mode should be set as leader for the group member to be active. |
| Step 3 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring Transmit Power Control
Configuring Transmit Power (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | On the 5 GHz Band or 2.4 GHz Band tab, click the TPC tab. |
| Step 3 | Choose of the following dynamic transmit power assignment modes:
|
| Step 4 | Enter the maximum and minimum power level assignment on this radio. If you configure maximum transmit power, RRM does not allow any access point attached to the device to exceed this transmit power level (whether the power is set by RRM TPC or by coverage hole detection). For example, if you configure a maximum transmit power of 11 dBm, then no access point would transmit above 11 dBm, unless the access point is configured manually. The range is –10 dBm to 30 dBm. |
| Step 5 | In the Power Threshold field, enter the cutoff signal level used by RRM when determining whether to reduce an access point's power. The default value for this parameter varies depending on the TPC version you choose. For TPCv1, the default value is –70 dBm, and for TPCv2, the default value is –67 dBm. The default value can be changed when access points are transmitting at higher (or lower) than desired power levels. The range for this parameter is –80 to –50 dBm. Increasing this value (between –65 and –50 dBm) causes the access points to operate at higher transmit power rates. Decreasing the value has the opposite effect. In applications with a dense population of access points, it may be useful to decrease the threshold to –80 or –75 dBm in order to reduce the number of BSSIDs (access points) and beacons seen by the wireless clients. Some wireless clients might have difficulty processing a large number of BSSIDs or a high beacon rate and might exhibit problematic behavior with the default threshold. |
| Step 6 | Click Apply. |
Configuring the Tx-Power Control Threshold (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm tpc-threshold threshold_value Example: | Configures the Tx-power control threshold used by RRM for auto power assignment. The range is from –80 to –50. |
| Step 3 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring the Tx-Power Level (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm txpower{trans_power_level | auto | max | min | once} Example: | Configures the 802.11 tx-power level
|
| Step 3 | end Example: | Returns to privileged EXEC mode. |
Configuring 802.11 RRM Parameters
Configuring Advanced 802.11 Channel Assignment Parameters (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | In the DCA tab, choose a Channel Assignment Mode to specify the DCA mode:
|
| Step 3 | From the Interval drop-down list, choose the interval that tells how often the DCA algorithm is allowed to run. The default interval is 10 minutes. |
| Step 4 | From the AnchorTime drop-down list, choose a number to specify the time of day when the DCA algorithm must start. The options are numbers between 0 and 23 (inclusive) representing the hour of the day from 12:00 a.m. to 11:00 p.m. |
| Step 5 | Check the Avoid Foreign AP Interference check box to cause the device's RRM algorithms to consider 802.11 traffic from foreign APs (those not included in your wireless network) when assigning channels to lightweight APs, or uncheck it to disable this feature. For example, RRM may adjust the channel assignment to have access points avoid channels close to foreign APs. By default, this feature is in enabled state. |
| Step 6 | Check the Avoid Cisco AP Load check box to cause the device's RRM algorithms to consider 802.11 traffic from Cisco lightweight APs in your wireless network when assigning channels. For example, RRM can assign better reuse patterns to access points that carry a heavier traffic load. By default, this feature is in disabled state. |
| Step 7 | Check the Avoid Non-802.11a Noise check box to cause the device's RRM algorithms to consider noise (non-802.11 traffic) in the channel when assigning channels to lightweight APs. For example, RRM may have APs avoid channels with significant interference from non-AP sources, such as microwave ovens. By default, this feature is in enabled state. |
| Step 8 | Check the Avoid Persistent Non-WiFi Interference check box to enable the device to ignore persistent non-WiFi interference. |
| Step 9 | From the DCA Channel Sensitivity drop-down list, choose one of the following options to specify how sensitive the DCA algorithm is to environmental changes such as signal, load, noise, and interference when determining whether to change channels:
|
| Step 10 | Set the Channel Width as required. You can choose the RF channel width as 20 MHz, 40 MHz, 80 MHz, 160 MHz, or Best. This is applicable only for 802.11a/n/ac (5 GHZ) radio. |
| Step 11 | The Auto-RF Channel List section shows the channels that are currently selected. To choose a channel, check the corresponding check box. |
| Step 12 | In the Event Driven RRM section, check the EDRRM check box to run RRM when CleanAir-enabled AP detects a significant level of interference. If enabled, set the sensitivity threshold level at which the RRM is invoked, enter the custom threshold, and check the Rogue Contribution check box to enter the rogue duty-cycle. |
| Step 13 | Click Apply. |
Configuring Advanced 802.11 Channel Assignment Parameters (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm channel cleanair-event sensitivity {high | low | medium} Example: | Configures CleanAir event-driven RRM parameters.
|
| Step 3 | ap dot11 {24ghz | 5ghz} rrm channel dca {add channel-number | anchor-time | global {auto | once} | interval | min-metric | remove channel-number | sensitivity {high | low | medium}} Example: | Configures Dynamic Channel Assignment (DCA) algorithm parameters for the 802.11 band.
|
| Step 4 | ap dot11 5ghz rrm channel dca chan-width {20 | 40 | 80 | best | 160 | best maximum {20 | 40 | 80 | MAX}} Example: | |
| Step 5 | ap dot11 5ghz rrm channel dca chan-width width-max {WIDTH_20MHz | WIDTH_40MHz | WIDTH_80MHz | WIDTH_MAX} Example: | Configures the maximum channel bandwidth that can be assigned to a channel. In this example, WIDTH_80MHz assigns the channel bandwidth to 20 MHz, 40 MHz, or 80 MHz but not greater than that. |
| Step 6 | ap dot11 {24ghz | 5ghz} rrm channel device Example: | Configures the persistent non-Wi-Fi device avoidance in the 802.11 channel assignment. |
| Step 7 | ap dot11 {24ghz | 5ghz} rrm channel foreign Example: | Configures the foreign AP 802.11 interference avoidance in the channel assignment. |
| Step 8 | ap dot11 {24ghz | 5ghz} rrm channel load Example: | Configures the Cisco AP 802.11 load avoidance in the channel assignment. |
| Step 9 | ap dot11 {24ghz | 5ghz} rrm channel noise Example: | Configures the 802.11 noise avoidance in the channel assignment. |
| Step 10 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring 802.11 Coverage Hole Detection (GUI)
Procedure
| Step 1 | Choose to configure Radio Resource Management parameters for 802.11a/n/ac (5-GHz) and 802.11b/g/n (2.4-GHz) radios. |
| Step 2 | On theRadio Resource Management page, click Coverage tab. |
| Step 3 | To enable coverage hole detection, check the Enable Coverage Hole Detection check box. |
| Step 4 | In the Data Packet Count field, enter the number of data packets. |
| Step 5 | In the Data Packet Percentage field, enter the percentage of data packets. |
| Step 6 | In the Data RSSI Threshold field, enter the actual value in dBm. Value ranges from -60 dBm to -90 dBm; the default value is –80 dBm. |
| Step 7 | In the Voice Packet Count field, enter the number of voice data packets. |
| Step 8 | In the Voice Packet Percentage field, enter the percentage of voice data packets. |
| Step 9 | In the Voice RSSI Threshold field, enter the actual value in dBm. Value ranges from -60 dBm to -90 dBm; the default value is –80 dBm. |
| Step 10 | In the Minimum Failed Client per AP field, enter the minimum number of clients on an AP with a signal-to-noise ratio (SNR) below the coverage threshold. Value ranges from 1 to 75 and the default value is 3. |
| Step 11 | In the Percent Coverage Exception Level per AP field, enter the maximum desired percentage of clients on an access point's radio operating below the desired coverage threshold and click Apply. Value ranges from 0 to 100% and the default value is 25%. |
Configuring 802.11 Coverage Hole Detection (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm coverage data{fail-percentage | packet-count | rssi-threshold} Example: | Configures the 802.11 coverage hole detection for data packets.
|
| Step 3 | ap dot11 {24ghz | 5ghz} rrm coverage exception global exception level Example: | Configures the 802.11 Cisco AP coverage exception level as a percentage that ranges from 0 to 100%. |
| Step 4 | ap dot11 {24ghz | 5ghz} rrm coverage level global cli_min exception level Example: | Configures the 802.11 Cisco AP client minimum exception level that ranges from 1 to 75 clients. |
| Step 5 | ap dot11 {24ghz | 5ghz} rrm coverage voice{fail-percentage | packet-count | rssi-threshold} Example: | Configures the 802.11 coverage hole detection for voice packets.
|
| Step 6 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring 802.11 Event Logging (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 24ghz | 5ghz rrm logging{channel | coverage | foreign | load | noise | performance | txpower} Example: | Configures event-logging for various parameters.
|
| Step 3 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring 802.11 Statistics Monitoring (GUI)
Procedure
| Step 1 | Choose to configure Radio Resource Management parameters for 802.11a/n/ac (5 GHz) and 802.11b/g/n (2.4 GHz) radios. |
| Step 2 | In the Monitor Intervals(60 to 3600secs) section, proceed as follows:
|
| Step 3 | Click Apply. |
Configuring 802.11 Statistics Monitoring (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 24ghz | 5ghz rrm monitor channel-list{all | country | dca} Example: | Sets the 802.11 monitoring channel-list for parameters such as noise/interference/rogue.
|
| Step 3 | ap dot11 24ghz | 5ghz rrm monitor coverage interval Example: | Configures the 802.11 coverage measurement interval in seconds that ranges from 60 to 3600. |
| Step 4 | ap dot11 24ghz | 5ghz rrm monitor load interval Example: | Configures the 802.11 load measurement interval in seconds that ranges from 60 to 3600. |
| Step 5 | ap dot11 24ghz | 5ghz rrm monitor noise interval Example: | Configures the 802.11 noise measurement interval (channel scan interval) in seconds that ranges from 60 to 3600. |
| Step 6 | ap dot11 24ghz | 5ghz rrm monitor signal interval Example: | Configures the 802.11 signal measurement interval (neighbor packet frequency) in seconds that ranges from 60 to 3600. |
| Step 7 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
Configuring the 802.11 Performance Profile (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | On the AP Join page, click the name of the profile or click Add to create a new one. |
| Step 3 | In the Add/Edit RF Profile window, click the RRM tab. |
| Step 4 | In the General tab that is displayed, enter the following parameters:
|
| Step 5 | Click Update & Apply to Device. |
Configuring the 802.11 Performance Profile (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | configure terminal Example: | Enters global configuration mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm profile clients cli_threshold_value Example: | Sets the threshold value for 802.11 Cisco AP clients that range between 1 and 75 clients. |
| Step 3 | ap dot11 {24ghz | 5ghz}rrm profile foreign int_threshold_value Example: | Sets the threshold value for 802.11 foreign interference that ranges between 0 and 100%. |
| Step 4 | ap dot11 {24ghz | 5ghz} rrm profile noise for_noise_threshold_value Example: | Sets the threshold value for 802.11 foreign noise ranges between –127 and 0 dBm. |
| Step 5 | ap dot11 {24ghz | 5ghz} rrm profile throughput throughput_threshold_value Example: | Sets the threshold value for 802.11 Cisco AP throughput that ranges between 1000 and 10000000 bytes per second. |
| Step 6 | ap dot11 {24ghz | 5ghz} rrm profile utilization rf_util_threshold_value Example: | Sets the threshold value for 802.11 RF utilization that ranges between 0 to 100%. |
| Step 7 | end Example: | Returns to privileged EXEC mode. |
Configuring Advanced 802.11 RRM
Enabling Channel Assignment (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | In the RRM page, click the relevant band's tab: either 5 GHz Band or 2.4 GHz Band. |
| Step 3 | Click the DCA tab |
| Step 4 | In the Dynamic Channel Assignment Algorithm section, choose the appropriate Channel Assignment Mode from these options:
|
| Step 5 | Click Apply. |
Enabling Channel Assignment (CLI)
Procedure
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 | enable Example: | Enters privileged EXEC mode. | ||
| Step 2 | ap dot11 {24ghz | 5ghz} rrm channel-update Example: | Enables the 802.11 channel selection update for each of the Cisco access points.
|
Restarting DCA Operation
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | enable Example: | Enters privileged EXEC mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm dca restart Example: | Restarts the DCA cycle for 802.11 radio. |
Updating Power Assignment Parameters (GUI)
Procedure
| Step 1 | Choose . |
| Step 2 | On the Access Points page, click the AP name from the 5GHz or 2.4 GHz list. |
| Step 3 | In the section, choose Custom from the Assignment Method droup-down list. |
| Step 4 | Choose the value for Transmit Power from the drop-down list. |
| Step 5 | Click Update & Apply to Device. |
Updating Power Assignment Parameters (CLI)
Procedure
| Command or Action | Purpose | |
|---|---|---|
| Step 1 | enable Example: | Enters privileged EXEC mode. |
| Step 2 | ap dot11 {24ghz | 5ghz} rrm txpower update Example: | Updates the 802.11 transmit power for each of the Cisco access points. |
Configuring Rogue Access Point Detection in RF Groups
Configuring Rogue Access Point Detection in RF Groups (CLI)
Before you begin
Ensure that each controller in the RF group has been configured with the same RF group name.
Note | The name is used to verify the authentication IE in all beacon frames. If the controller have different names, false alarms will occur. |
Procedure
| Command or Action | Purpose | |||||
|---|---|---|---|---|---|---|
| Step 1 | ap name Cisco_AP mode { monitor | clear | sensor | sniffer } Example: | Perform this step for every access point connected to the controller . Configures the following AP modes of operation:
| ||||
| Step 2 | end Example: | Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. | ||||
| Step 3 | configure terminal Example: | Enters global configuration mode. | ||||
| Step 4 | wireless wps ap-authentication Example: | Enables rogue access point detection. | ||||
| Step 5 | wireless wps ap-authentication threshold value Example: | Specifies when a rogue access point alarm is generated. An alarm occurs when the threshold value (which specifies the number of access point frames with an invalid authentication IE) is met or exceeded within the detection period. The valid threshold range is from 1 to 255, and the default threshold value is 1. To avoid false alarms, you may want to set the threshold to a higher value.
|
Monitoring RRM Parameters and RF Group Status
Monitoring RRM Parameters
| Commands | Description |
|---|---|
| show ap dot11 24ghz channel | Displays the configuration and statistics of the 802.11b channel assignment. |
| show ap dot11 24ghz coverage | Displays the configuration and statistics of the 802.11b coverage. |
| show ap dot11 24ghz group | Displays the configuration and statistics of the 802.11b grouping. |
| show ap dot11 24ghz logging | Displays the configuration and statistics of the 802.11b event logging. |
| show ap dot11 24ghz monitor | Displays the configuration and statistics of the 802.11b monitoring. |
| show ap dot11 24ghz profile | Displays 802.11b profiling information for all Cisco APs. |
| show ap dot11 24ghz summary | Displays the configuration and statistics of the 802.11b Cisco APs. |
| show ap dot11 24ghz txpower | Displays the configuration and statistics of the 802.11b transmit power control. |
| show ap dot11 5ghz channel | Displays the configuration and statistics of the 802.11a channel assignment. |
| show ap dot11 5ghz coverage | Displays the configuration and statistics of the 802.11a coverage. |
| show ap dot11 5ghz group | Displays the configuration and statistics of the 802.11a grouping. |
| show ap dot11 5ghz logging | Displays the configuration and statistics of the 802.11a event logging. |
| show ap dot11 5ghz monitor | Displays the configuration and statistics of the 802.11a monitoring. |
| show ap dot11 5ghz profile | Displays 802.11a profiling information for all Cisco APs. |
| show ap dot11 5ghz summary | Displays the configuration and statistics of the 802.11a Cisco APs. |
| show ap dot11 5ghz txpower | Displays the configuration and statistics of the 802.11a transmit power control. |
Verifying RF Group Status (CLI)
This section describes the new commands for RF group status.
The following commands can be used to verify RF group status on the .
| Command | Purpose |
| show ap dot11 5ghz group | Displays the controller name which is the RF group leader for the 802.11a RF network. |
| show ap dot11 24ghz group | Displays the controller name which is the RF group leader for the 802.11b/g RF network. |
Examples: RF Group Configuration
Device # configure terminal Device (config)# wireless rf-network test1 Device (config)# ap dot11 24ghz shutdown Device (config)# end Device # show network profile 5 Device # ap name ap1 mode clear Device # end Device # configure terminal Device (config)# wireless wps ap-authentication Device (config)# wireless wps ap-authentication threshold 50 Device (config)# end Information About ED-RRM
Spontaneous interference is interference that appears suddenly on a network, perhaps jamming a channel or a range of channels completely. The Cisco CleanAir spectrum event-driven RRM feature allows you to set a threshold for air quality (AQ) that, if exceeded, triggers an immediate channel change for the affected access point. Once a channel change occurs due to event-driven RRM, the channel is blocked list for three hours to avoid selection. Most RF management systems can avoid interference, but this information takes time to propagate through the system. Cisco CleanAir relies on AQ measurements to continuously evaluate the spectrum and can trigger a move within 30 seconds. For example, if an access point detects interference from a video camera, it can recover by changing channels within 30 seconds of the camera becoming active.
Configuring ED-RRM on the Cisco Wireless LAN Controller (CLI)
Procedure
| Step 1 | Trigger spectrum event-driven radio resource management (RRM) to run when a Cisco CleanAir-enabled access point detects a significant level of interference by entering these commands: ap dot11 {24ghz | 5ghz} rrm channel cleanair-event —Configures CleanAir driven RRM parameters for the 802.11 Cisco lightweight access points. ap dot11 {24ghz | 5ghz} rrm channel cleanair-event sensitivity {low | medium | high | custom} —Configures CleanAir driven RRM sensitivity for the 802.11 Cisco lightweight access points. Default selection is Medium. ap dot11 { 24ghz | 5ghz } rrm channel cleanair-event custom-threshold custom-threshold-value —Triggers the ED-RRM event at the set threshold value. The custom threshold values range from 1 to 99. ap dot11 {24ghz | 5ghz} rrm channel cleanair-event rogue-contribution —Enables rogue contribution. ap dot11 {24ghz | 5ghz} rrm channel cleanair-event rogue-contribution duty-cycle thresholdvalue —Configures threshold value for rogue contribution. The valid range is from 1 to 99, with 80 as the default. |
| Step 2 | Save your changes by entering this command: write memory |
| Step 3 | See the CleanAir configuration for the 802.11a/n/ac or 802.11b/g/n network by entering this command: show ap dot11 {24ghz | 5ghz} cleanair config Information similar to the following appears: |
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Source: https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/radio-resource-management.html
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