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Ensure that the switch has access points connected to it.
Configure SSID.
The following are the restrictions that you should keep in mind while configuring voice and video parameters:
SIP CAC can be used for the 9971 Cisco phones that support TSPEC-based admission control. You can also use the phones that support Status code 17.
SIP snooping is supported for providing voice priority to the non-TSPEC SIP phones.
TSPEC for video CAC is not supported.
Three parameters on the switch affect voice and/or video quality:
Call Admission Control
Expedited bandwidth requests
Unscheduled automatic power save delivery
Call Admission Control (CAC) and UAPSD are supported on Cisco Compatible Extensions (CCX) v4 and v5; however, these parameters are also supported even without CCX but on any device implementing WMM (that supports 802.1e). Expedited bandwidth requests are supported only on CCXv5.
Traffic stream metrics (TSM) can be used to monitor and report issues with voice quality.
Call Admission Control (CAC) enables an access point to maintain controlled quality of service (QoS) when the wireless LAN is experiencing congestion. The WMM protocol deployed in CCXv4 maintains QoS under differing network loads.
Two types of Over The Air (OTA) CAC are available: static-based CAC and load-based CAC.
User-defined policies: You can define your own QoS policies. You can have more control over these policies than the existing metal policies.
System-defined precious metal policies: To support backward compatibility.
Platinum: Used for VoIP clients.
Gold: Used for video clients.
Silver: Used for best effort traffic.
Bronze: Used for NRT traffic.
Voice over WLAN applications supporting WMM and TSPEC can specify how much bandwidth or shared medium time is required to initiate a call. Bandwidth-based, or static, CAC enables the access point to determine whether it is capable of accommodating a particular call. The access point rejects the call if necessary in order to maintain the maximum allowed number of calls with acceptable quality.
The QoS setting for a WLAN determines the level of bandwidth-based CAC support. To use bandwidth-based CAC with voice applications, the WLAN must be configured for Platinum QoS. With bandwidth-based CAC, the access point bandwidth availability is determined based on the amount of bandwidth currently used by the access point clients, to which the bandwidth requested by the Voice over WLAN applications is added. If this total exceeds a configured bandwidth threshold, the new call is rejected.
 Note |
You must enable admission control (ACM) for CCXv4 clients that have WMM enabled. Otherwise, bandwidth-based CAC does not operate properly for these CCXv4 clients. |
Load-based CAC incorporates a measurement scheme that takes into account the bandwidth consumed by all traffic types (including that from clients), cochannel access point loads, and coallocated channel interference, for voice and video applications. Load-based CAC also covers the additional bandwidth consumption resulting from PHY and channel impairment.
In load-based CAC, the access point continuously measures and updates the utilization of the RF channel (that is, the mean time of bandwidth that has been exhausted), channel interference, and the additional calls that the access point can admit. The access point admits a new call only if the channel has enough unused bandwidth to support that call. By doing so, load-based CAC prevents oversubscription of the channel and maintains QoS under all conditions of WLAN loading and interference.
Note |
If you disable load-based CAC, the access points start using bandwidth-based CAC. |
IOSd Call Admission Control (CAC) controls bandwidth availability from switch to access point.
You can configure class-based, unconditional packet marking features on your switch for CAC.
CAC is a concept that applies to voice and video traffic only—not data traffic. If an influx of data traffic oversubscribes a particular link in the network, queueing, buffering, and packet drop decisions resolve the congestion. The extra traffic is simply delayed until the interface becomes available to send the traffic, or, if traffic is dropped, the protocol or the end user initiates a timeout and requests a retransmission of the information.
Network congestion cannot be resolved in this manner when real-time traffic, sensitive to both latency and packet loss, is present, without jeopardizing the quality of service (QoS) expected by the users of that traffic. For real-time delay-sensitive traffic such as voice, it is better to deny network access under congestion conditions than to allow traffic onto the network to be dropped and delayed, causing intermittent impaired QoS and resulting in customer dissatisfaction.
CAC is therefore a deterministic and informed decision that is made before a voice call is established and is based on whether the required network resources are available to provide suitable QoS for the new call.
Based on the admit CAC CLI configuration in addition to the existing CAC algorithm, switch allows either voice or video with TSPEC or SIP snooping. The admit cac CLI is mandatory for the voice call to pass through.
If the BSSID policer is configured for the voice or video traffic, then additional checks are performed on the packets.
The expedited bandwidth request feature enables CCXv5 clients to indicate the urgency of a WMM traffic specifications (TSPEC) request (for example, an e911 call) to the WLAN. When the controller receives this request, it attempts to facilitate the urgency of the call in any way possible without potentially altering the quality of other TSPEC calls that are in progress.
You can apply expedited bandwidth requests to both bandwidth-based and load-based CAC. Expedited bandwidth requests are disabled by default. When this feature is disabled, the controller ignores all expedited requests and processes TSPEC requests as normal TSPEC requests.
The following table lists examples of TSPEC request handling for normal TSPEC requests and expedited bandwidth requests.
|
CAC Mode |
Reserved bandwidth for voice calls |
Usage |
Normal TSPEC Request |
TSPEC with Expedited Bandwidth Request |
|---|---|---|---|---|
|
Bandwidth-based CAC |
75% (default setting) |
Less than 75% |
Admitted |
Admitted |
|
Between 75% and 90% (reserved bandwidth for voice calls exhausted) |
Rejected |
Admitted |
||
|
More than 90% |
Rejected |
Rejected |
||
|
Load-based CAC |
Less than 75% |
Admitted |
Admitted |
|
|
Between 75% and 85% (reserved bandwidth for voice calls exhausted) |
Rejected |
Admitted |
||
|
More than 85% |
Rejected |
Rejected |
Note |
Admission control for TSPEC G711-20ms and G711-40 ms codec types are supported. |
Unscheduled automatic power save delivery (U-APSD) is a QoS facility defined in IEEE 802.11e that extends the battery life of mobile clients. In addition to extending battery life, this feature reduces the latency of traffic flow delivered over the wireless media. Because U-APSD does not require the client to poll each individual packet buffered at the access point, it allows delivery of multiple downlink packets by sending a single uplink trigger packet. U-APSD is enabled automatically when WMM is enabled.
In a voice-over-wireless LAN (VoWLAN) deployment, traffic stream metrics (TSM) can be used to monitor voice-related metrics on the client-access point air interface. It reports both packet latency and packet loss. You can isolate poor voice quality issues by studying these reports.
The metrics consist of a collection of uplink (client side) and downlink (access point side) statistics between an access point and a client device that supports CCX v4 or later releases. If the client is not CCX v4 or CCXv5 compliant, only downlink statistics are captured. The client and access point measure these metrics. The access point also collects the measurements every 5 seconds, prepares 90-second reports, and then sends the reports to the controller. The controller organizes the uplink measurements on a client basis and the downlink measurements on an access point basis and maintains an hour’s worth of historical data. To store this data, the controller requires 32 MB of additional memory for uplink metrics and 4.8 MB for downlink metrics.
TSM can be configured through either the GUI or the CLI on a per radio-band basis (for example, all 802.11a radios). The controller saves the configuration in flash memory so that it persists across reboots. After an access point receives the configuration from the controller, it enables TSM on the specified radio band.
This table shows the upper limit for TSM entries in different controller series.
|
TSM Entries |
5700 |
|---|---|
|
MAX AP TSM entries |
100 |
|
MAX Client TSM entries |
250 |
|
MAX TSM entries |
100*250=25000 |
Note |
Once the upper limit is reached, additional TSM entries cannot be stored and sent to WCS or NCS. If client TSM entries are full and AP TSM entries are available, then only the AP entries are stored, and viceversa. This leads to partial output. TSM cleanup occurs every one hour. Entries are removed only for those APs and clients that are not in the system. |
You can configure a switch to provide support for SIP calls from VoWLAN clients that do not support TSPEC-based calls. This feature is known as SIP CAC support. If bandwidth is available in the configured voice pool, the SIP call uses the normal flow and the switch allocates the bandwidth to those calls.
You can also prioritize up to six preferred call numbers. When a call comes to one of the configured preferred numbers, the switch does not check the configured maximum voice bandwidth. The switch allocates the bandwidth needed for the call, even if it exceeds the maximum bandwidth for voice configured for voice CAC. The preferred call will be rejected if bandwidth allocation exceeds 85% of the radio bandwidth. The bandwidth allocation is 85 percent of the entire bandwidth pool, not just from the maximum configured voice pool. The bandwidth allocation is the same even for roaming calls.
Set WLAN QoS to allow voice calls to pass through.
Enable ACM for the radio.
Enable SIP call snooping on the WLAN.
Enhanced distributed channel access (EDCA) parameters are designed to provide preferential wireless channel access for voice, video, and other quality-of-service (QoS) traffic.
How to Configure Voice and Video Parameters
Ensure that you have configured SIP-based CAC.
You should have created a class map for CAC before beginning this procedure.
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
show wlan summary Example: |
Specifies all of the WLANs configured on the switch. |
| Step 2 |
show wlan wlan_id Example: |
Specifies the WLAN that you plan to modify. For voice over WLAN, ensure that the WLAN is configured for WMM and the QoS level is set to Platinum. |
| Step 3 |
configure terminal Example: |
Enters global configuration mode. |
| Step 4 |
policy-map policy-map name Example: |
Enters policy map configuration mode. Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy. In WLAN, you need to configure service-policy for these commands to take effect. |
| Step 5 |
class {class-name | class-default} Example: |
Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Specifies the name of the class whose policy you want to create or change. You can also create a system default class for unclassified packets. |
| Step 6 |
admit cac wmm-tspec Example: |
(Optional) Admits the request for Call Admission Control (CAC) for policy map. |
| Step 7 |
service-policy policy-map name Example: |
Configures the QoS service policy. |
| Step 8 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
| Step 9 |
wlan wlan_profile_name wlan_ID SSID_network_name wlan shutdown Example: |
Disables all WLANs with WMM enabled prior to changing the video parameters. |
| Step 10 |
wlan wlan_profile_name wlan_ID SSID_network_name Example: |
Disables all WLANs with WMM enabled prior to changing the voice parameters. |
| Step 11 |
wlan wlan_name call-snoop Example: |
Enables the call-snooping on a particular WLAN. |
| Step 12 |
wlan wlan_name service-policy input input_policy_name Example: |
Configures input SSID policy on a particular WLAN to voice. |
| Step 13 |
wlan wlan_name service-policy output ouput_policy_name Example: |
Configures output SSID policy on a particular WLAN to voice. |
| Step 14 |
wlan wlan_name service-policy input ingress_policy_name Example: |
Configures ingress SSID policy on a particular WLAN as user-defined policy. |
| Step 15 |
wlan wlan_name service-policy output egress_policy_name Example: |
Configures egress SSID policy on a particular WLAN as user-defined policy. |
| Step 16 |
ap dot11 {5ghz | 24ghz} shutdown Example: |
Disables the radio network. |
| Step 17 |
ap dot11 {5ghz | 24ghz} cac voice sip Example: |
Enables or disables SIP IOSd CAC for the 802.11a or 802.11b/g network. |
| Step 18 |
ap dot11 {5ghz | 24ghz} cac voice acm Example: |
Enables or disables bandwidth-based voice CAC for the 802.11a or 802.11b/g network. |
| Step 19 |
ap dot11 {5ghz | 24ghz} cac voice max-bandwidth bandwidth Example: |
Sets the percentage of maximum bandwidth allocated to clients for voice applications on the 802.11a or 802.11b/g network. The bandwidth range is 5 to 85%, and the default value is 75%. Once the client reaches the value specified, the access point rejects new videos on this network. |
| Step 20 |
ap dot11 {5ghz | 24ghz} cac voice roam-bandwidth bandwidth Example: |
Sets the percentage of maximum allocated bandwidth reserved for roaming voice clients. The bandwidth range is 0 to 25%, and the default value is 6%. The switch reserves this much bandwidth from the maximum allocated bandwidth for roaming voice clients. |
| Step 21 |
no wlan shutdown Example: |
Reenables all WLANs with WMM enabled. |
| Step 22 |
no ap dot11 {5ghz | 24ghz} shutdown Example: |
Reenables the radio network. |
| Step 23 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
show wlan summary Example: |
Specifies all of the WLANs configured on the switch. |
| Step 2 |
show wlan wlan_id Example: |
Specifies the WLAN that you plan to modify. |
| Step 3 |
configure terminal Example: |
Enters global configuration mode. |
| Step 4 |
policy-map policy-map name Example: |
Enters policy map configuration mode. Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy. In WLAN, you need to configure service-policy for these commands to take effect. |
| Step 5 |
class {class-name | class-default} Example: |
Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Specifies the name of the class whose policy you want to create or change. You can also create a system default class for unclassified packets. |
| Step 6 |
admit cac wmm-tspec Example: |
(Optional) Admits the request for Call Admission Control (CAC) for policy map. |
| Step 7 |
service-policy policy-map name Example: |
Configures the QoS service policy. |
| Step 8 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
| Step 9 |
wlanwlan_profile_name Example: |
Disables all WLANs with WMM enabled prior to changing the video parameters. |
| Step 10 |
ap dot11 {5ghz | 24ghz} shutdown Example: |
Disables the radio network. |
| Step 11 |
ap dot11 {5ghz | 24ghz} cac video acm Example: |
Enables or disables bandwidth-based video CAC for the 802.11a or 802.11b/g network. |
| Step 12 |
ap dot11 {5ghz | 24ghz} cac video load-based Example: |
Configures the load-based CAC method. If you do not enter this command, then the default static CAC is applied. |
| Step 13 |
ap dot11 {5ghz | 24ghz} cac video max-bandwidth bandwidth Example: |
Sets the percentage of maximum bandwidth allocated to clients for video applications on the 802.11a or 802.11b/g network. The bandwidth range is 5 to 85%, and the default value is 75%. The default value is 0, which means no bandwidth request control. The sum of the voice bandwidth and video bandwidth should not exceed 85% or configured maximum media bandwidth. |
| Step 14 |
ap dot11 {5ghz | 24ghz} cac video roam-bandwidth bandwidth Example: |
Sets the percentage of maximum allocated bandwidth reserved for roaming clients for video. The bandwidth range is 0 to 25%, and the default value is 0%. |
| Step 15 |
no wlan shutdown wlan_id Example: |
Reenables all WLANs with WMM enabled. |
| Step 16 |
no ap dot11 {5ghz | 24ghz} shutdown Example: |
Reenables the radio network. |
| Step 17 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
SIP CAC controls the total number of SIP calls that can be made.
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
configure terminal Example: |
Enters global configuration mode. |
| Step 2 |
wlan wlan-name Example: |
Enters WLAN configuration submode. |
| Step 3 |
call-snoop Example: |
Enables the call-snooping feature for a particular WLAN. |
| Step 4 |
service-policy [client] input policy-map name Example: |
Assigns a policy map to WLAN input traffic. Ensure that you provide QoS policy to voice for input traffic. |
| Step 5 |
service-policy [client] output policy-map name Example: |
Assigns policy map to WLAN output traffic. Ensure that you provide QoS policy to voice for output traffic. |
| Step 6 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
| Step 7 |
show wlan {wlan-id | wlan-name} Example: |
Verifies the configured QoS policy on the WLAN. |
| Step 8 |
configure terminal Example: |
Enters global configuration mode. |
| Step 9 |
ap dot11 {5ghz | 24ghz} cac {voice | video} acm Example: |
Enables the ACM static on the radio. When enabling SIP snooping, use the static CAC, not the load-based CAC. |
| Step 10 |
ap dot11 {5ghz | 24ghz} cac voice sip Example: |
Configures SIP-based CAC. |
| Step 11 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
You must set the following parameters before configuring a preferred call number.
Set WLAN QoS to voice.
Enable ACM for the radio.
Enable SIP call snooping on the WLAN.
Enable SIP-based CAC.
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
configure terminal Example: |
Enters global configuration mode. |
| Step 2 |
wlan wlan-name qos platinum Example: |
Sets QoS to voice on a particular WLAN. |
| Step 3 |
ap dot11 {5ghz | 24ghz} cac {voice | video} acm Example: |
Enables the static ACM on the radio. When enabling SIP snooping, use the static CAC, not the load-based CAC. |
| Step 4 |
wlan wlan-name Example: |
Enables the call-snooping feature for a particular WLAN. |
| Step 5 |
wireless sip preferred-call-no call_index call_number Example: |
Adds a new preferred call. |
| Step 6 |
no wireless sip preferred-call-no call_index Example: |
Removes a preferred call. |
| Step 7 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
configure terminal Example: |
Enters global configuration mode. |
| Step 2 |
ap dot11 {5ghz | 24ghz } shutdown Example: |
Disables the radio network. |
| Step 3 |
ap dot11 {5ghz | 24ghz} edca-parameters {custom-voice | optimized-video-voice | optimized-voice | svp-voice | wmm-default} Example: |
|
| Step 4 |
show ap dot11 {5ghz | 24ghz} network Example: |
Displays the current status of MAC optimization for voice. |
| Step 5 |
no ap dot11 {5ghz | 24ghz} shutdown Example: |
Reenables the radio network. |
| Step 6 |
end Example: |
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-Z to exit global configuration mode. |
| Step 1 |
Choose or to open EDCA Parameters page. |
||
| Step 2 |
Choose one of the following options from the EDCA Profile drop-down list:
|
||
| Step 3 |
If you want to enable MAC optimization for voice, select the Enable Low Latency MAC check box. Otherwise, leave this check box unselected, which is the default value. This feature enhances voice performance by controlling packet retransmits and appropriately aging out voice packets on lightweight access points, which improves the number of voice calls serviced per access point.
|
||
| Step 4 |
Click Apply to commit your changes. |
||
| Step 5 |
To reenable the radio network, choose Network under 802.11a/n or 802.11b/g/n, select the 802.11a/n/ac (or 802.11b/g/n) Network Status check box, and click Apply. |
||
| Step 6 |
Click Save Configuration. |
This section describes the new commands for the voice and video parameters.
The following commands can be used to monitor voice and video parameters.
|
Command |
Purpose |
||
| show ap dot11 {5ghz | 24ghz} network |
Displays the radio-based statistics for voice. |
||
| show ap name ap_name dot11 24ghz tsm all |
Displays the TSM voice metrics and current status of MAC optimization for voice. |
||
| show ap name apname cac voice |
Displays the information about CAC for a particular access point. |
||
| show client detail client_mac |
Displays the U-APSD status for a particular client. |
||
| show policy-map interface wireless client |
Displays the video client policy details. |
||
| show access-list |
Displays the video client dynamic access-list from the switch. |
||
| show wireless client voice diag status |
Displays information about whether voice diagnostics are enabled or disabled. If enabled, this also displays information about the clients in the watch list and the time remaining for the diagnostics of the voice call.
|
||
| show wireless client voice diag tspec |
Displays the TSPEC information sent from the clients that are enabled for voice diagnostics. |
||
| show wireless client voice diag qos-map |
Displays information about the QoS/DSCP mapping and packet statistics in each of the four queues: VO, VI, BE, BK. The different DSCP values are also displayed. |
||
| show wireless client voice diag rssi |
Display the client’s RSSI values in the last 5 seconds when voice diagnostics is enabled. |
||
| show client voice-diag roam-history |
Displays information about the last three roaming calls. The output contains the timestamp, access point associated with roaming, roaming reason, and if there is a roaming failure, reason for roaming-failure. |
||
| show policy-map interface wireless mac mac-address |
Displays information about the voice and video data packet statistics. |
||
| show wireless media-stream client summary |
Displays a summary of the media stream and video client information. |
||
| show controllers d0 | b queue |
Displays which queue the packets are going through on an access point. |
||
| show platform qos queue stats interface |
Displays which queue packets are going through from the switch. |
You can monitor the video parameters using the following commands.
|
Command |
Purpose |
| show ap join stats summary ap_mac |
Displays the last join error detail for a specific access point. |
| show ip igmp snooping wireless mgid |
Displays the TSM voice metrics and current status of MAC optimization for voice. |
| show wireless media-stream multicast-direct state |
Displays the media stream multicast-direct parameters. |
| show wireless media-stream group summary |
Displays the summary of the media stream and client information. |
| show wireless media-stream group detail group_name |
Displays the details of a specific media-stream group. |
| show wireless media-stream client summary |
Displays the details for a set of media-stream clients. |
| show wireless media-stream client detail group_name |
Displays the details for a set of media-stream clients. |
| show ap dot11 {5ghz | 24ghz) media-stream rrc |
Display the details of media stream. |
| show wireless media-stream message details |
Displays information about the message configuration. |
| show ap name ap-name auto-rf dot11 5ghz | i Util |
Displays the details of channel utilization. |
| show controllers d0 | b queue |
Displays which queue the packets are going through on an access point based on 2.4- and 5-GHz bands. |
| show controllers d1 | b queue |
Displays which queue the packets are going through on an access point based on 2.4- and 5-GHz bands. |
| show cont d1 | b Media |
Displays the video metric details on the band A or B. |
| show capwap mcast mgid all |
Displays information about all of the multicast groups and their corresponding multicast group identifications (MGIDs) associated to the access point. |
| show capwap mcast mgid id id |
Displays information about all of the video clients joined to the multicast group in a specific MGID. |
| Related Topic | Document Title |
|---|---|
| Multicast configuration |
Multicast Configuration Guide, Cisco IOS XE Release 3SE (Cisco WLC 5700 Series) |
| VideoStream configuration |
VideoStream Configuration Guide, Cisco IOS XE Release 3SE (Cisco WLC 5700 Series) |
| Standard/RFC | Title |
|---|---|
| None |
— |
| MIB | MIBs Link |
|---|---|
| All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
| Description | Link |
|---|---|
|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
| Release | Feature Information |
|---|---|
| Cisco IOS XE 3.2SE | This feature was introduced. |
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