Configuring Dynamic WMM Queue Management
Traditional wireless networks provide all clients with equal bandwidth access. However, delays or reductions in throughput can adversely affect voice and video applications, resulting in disrupted VoIP Voice over IP. VoIP allows transmission of voice and multimedia content over an IP network. conversations or dropped frames in a streamed video. Thus, data streams that require strict latency and throughput need to be assigned higher traffic priority than other traffic types.
The Wi-Fi Wi-Fi is a technology that allows electronic devices to connect to a WLAN network, mainly using the 2.4 GHz and 5 GHz radio bands. Wi-Fi can apply to products that use any 802.11 standard. Alliance defined the Wi-Fi Wi-Fi is a technology that allows electronic devices to connect to a WLAN network, mainly using the 2.4 GHz and 5 GHz radio bands. Wi-Fi can apply to products that use any 802.11 standard. Multimedia (WMM Wi-Fi Multimedia. WMM is also known as WME. It refers to a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic QoS features to IEEE 802.11 networks. WMM prioritizes traffic according to four ACs: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK).) standard in response to industry requirements for QoS Quality of Service. It refers to the capability of a network to provide better service and performance to a specific network traffic over various technologies. support for multimedia applications for wireless networks. This is defined as per the IEEE Institute of Electrical and Electronics Engineers. 802.11e 802.11e is an enhancement to the 802.11a and 802.11b specifications that enhances the 802.11 Media Access Control layer with a coordinated Time Division Multiple Access (TDMA) construct. It adds error-correcting mechanisms for delay-sensitive applications such as voice and video. The 802.11e specification provides seamless interoperability between business, home, and public environments such as airports and hotels, and offers all subscribers high-speed Internet access with full-motion video, high-fidelity audio, and VoIP. standards.
the access point be Wi-Fi Wi-Fi is a technology that allows electronic devices to connect to a WLAN network, mainly using the 2.4 GHz and 5 GHz radio bands. Wi-Fi can apply to products that use any 802.11 standard. Certified and has WMM Wi-Fi Multimedia. WMM is also known as WME. It refers to a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic QoS features to IEEE 802.11 networks. WMM prioritizes traffic according to four ACs: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). enabled
the client device be Wi-Fi Wi-Fi is a technology that allows electronic devices to connect to a WLAN network, mainly using the 2.4 GHz and 5 GHz radio bands. Wi-Fi can apply to products that use any 802.11 standard. Certified
The following sections describe:
Enhanced Distributed Channel Access
Enhanced Distributed Channel Access
WMM Wi-Fi Multimedia. WMM is also known as WME. It refers to a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic QoS features to IEEE 802.11 networks. WMM prioritizes traffic according to four ACs: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). provides media access prioritization through Enhanced Distributed Channel Access (EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. ). EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. defines four ACs to prioritize traffic; voice, video, best effort, and background. These ACs correspond to 802.1p priority tags, as shown in Table 1.
|
WMM Access Category |
Description |
802.1p Tag |
|
Voice |
Highest priority |
7, 6 |
|
Video |
Prioritize video traffic above other data traffic |
5, 4 |
|
Best Effort |
Traffic from legacy devices or traffic from applications or devices that do not support QoS Quality of Service. It refers to the capability of a network to provide better service and performance to a specific network traffic over various technologies. |
0, 3 |
|
Background |
Low priority traffic (file downloads, print jobs) |
2, 1 |
While the WMM Wi-Fi Multimedia. WMM is also known as WME. It refers to a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic QoS features to IEEE 802.11 networks. WMM prioritizes traffic according to four ACs: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). ACs designate specific types of traffic, you can determine the priority of the ACs. For example, you can choose to give video traffic the highest priority. With WMM Wi-Fi Multimedia. WMM is also known as WME. It refers to a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic QoS features to IEEE 802.11 networks. WMM prioritizes traffic according to four ACs: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK)., applications assign data packets to an AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket.. In the client, the data packets are then added to one of the transmit queues for voice, video, best effort, or background.
WMM Wi-Fi Multimedia. WMM is also known as WME. It refers to a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic QoS features to IEEE 802.11 networks. WMM prioritizes traffic according to four ACs: voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). is an extension to the Distributed Coordination Function (DCF Distributed Coordination Function. DCF is a protocol that uses carrier sensing along with a four-way handshake to maximize the throughput while preventing packet collisions.) of the CSMA/CA Carrier Sense Multiple Access / Collision Avoidance. CSMA/CA is a protocol for carrier transmission in networks using the 802.11 standard. CSMA/CA aims to prevent collisions by listening to the broadcasting nodes, and informing devices not to transmit any data until the broadcasting channel is free. protocol. The collision resolution algorithm responsible for traffic prioritization depends on the following configurable parameters for each AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket.:
arbitrary inter-frame space number (AIFSN Arbitrary Inter-frame Space Number. AIFSN is set by the AP in beacon frames and probe responses. AIFS is a method of prioritizing a particular category of traffic over the other, for example prioritizing voice or video messages over email. )
minimum and maximum contention window (CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary.) size
For each AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket., the backoff time is the sum of the AIFSN Arbitrary Inter-frame Space Number. AIFSN is set by the AP in beacon frames and probe responses. AIFS is a method of prioritizing a particular category of traffic over the other, for example prioritizing voice or video messages over email. and a random value between 0 and the CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary. value. The AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket. with the lowest backoff time is granted the opportunity to transmit (TXOP Transmission Opportunity. TXOP is used in wireless networks supporting the IEEE 802.11e Quality of Service (QoS) standard. Used in both EDCA and HCF Controlled Channel Access modes of operation, TXOP is a bounded time interval in which stations supporting QoS are permitted to transfer a series of frames. TXOP is defined by a start time and a maximum duration.). Frames with the highest-priority AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket. are more likely to get TXOP Transmission Opportunity. TXOP is used in wireless networks supporting the IEEE 802.11e Quality of Service (QoS) standard. Used in both EDCA and HCF Controlled Channel Access modes of operation, TXOP is a bounded time interval in which stations supporting QoS are permitted to transfer a series of frames. TXOP is defined by a start time and a maximum duration., because they tend to have the lowest backoff times (a result of having smaller AIFSN Arbitrary Inter-frame Space Number. AIFSN is set by the AP in beacon frames and probe responses. AIFS is a method of prioritizing a particular category of traffic over the other, for example prioritizing voice or video messages over email. and CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary. parameter values). The value of the CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary. varies through time as the CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary. doubles after each collision up to the maximum CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary.. The CW Contention Window. In QoS, CW refers to a window set for access categories based on the type of traffic. Based on the type and volume of the traffic, the minimum and maximum values can be calculated to provide a wider window when necessary. is reset to the minimum value after successful transmission. In addition, you can configure the TXOP Transmission Opportunity. TXOP is used in wireless networks supporting the IEEE 802.11e Quality of Service (QoS) standard. Used in both EDCA and HCF Controlled Channel Access modes of operation, TXOP is a bounded time interval in which stations supporting QoS are permitted to transfer a series of frames. TXOP is defined by a start time and a maximum duration. duration for each AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket..
On the managed device, you configure the AC Access Category. As per the IEEE 802.11e standards, AC refers to various levels of traffic prioritization in Enhanced Distributed Channel Access (EDCA) operation mode. The WLAN applications prioritize traffic based on the Background, Best Effort, Video, and Voice access categories. AC can also refer to Alternating Current, a form of electric energy that flows when the appliances are plugged to a wall socket. priorities in the WLAN Wireless Local Area Network. WLAN is a 802.11 standards-based LAN that the users access through a wireless connection. EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. parameters profile. There are two sets of EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. profiles you can configure:
AP parameters affecting traffic from the AP to the client.
STA parameters affecting traffic from the client to the AP.
Configure EDCA Parameters
The following procedure describes how to define an Enhanced Distributed Channel Access (EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. ) profile for APs or for clients (stations):
1. In the node hierarchy, navigate to .
2. In , expand .
This example uses the default profile.
3. Select the or profile. Configure the EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. profile based on the parameters described in Table 2.
4. Click .
5. Click .
6. In the window, select the check box and click .
|
Parameter |
Description |
|
Best Effort |
Set the following parameters to define the best effort queue: : arbitrary inter-frame space number. Range: 1-15. : the exponential (n) value of the maximum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 1-15. : the exponential (n) value of the minimum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 0-15. : transmission opportunity, in units of 32 microseconds. Divide the desired transmission duration by 32 to determine the value to configure. For example, for a transmission duration of 3008 microseconds, enter 94 (3008/32). Range: 0-2047. : this parameter specifies mandatory admission control. With a value of , the client reserves the access category through traffic specification (TSPEC Traffic Specification. TSPEC allows an 802.11e client or a QoS-capable wireless client to signal its traffic requirements to the AP. ) signaling. A value of 0 disables this option. |
|
Background |
Set the following parameters to define the background queue: : arbitrary inter-frame space number. Range: 1-15. : the exponential (n) value of the maximum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 1-15. : the exponential (n) value of the minimum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 0-15. : transmission opportunity, in units of 32 microseconds. Divide the desired transmission duration by 32 to determine the value to configure. For example, for a transmission duration of 3008 microseconds, enter 94 (3008/32). Range: 0-2047. : this parameter specifies mandatory admission control. With a value of, the client reserves the access category through traffic specification (TSPEC Traffic Specification. TSPEC allows an 802.11e client or a QoS-capable wireless client to signal its traffic requirements to the AP. ) signaling. A value of 0 disables this option. |
|
Video |
Set the following parameters to define the background queue: : trbitrary inter-frame space number. Range: 1-15. : The exponential (n) value of the maximum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 1-15. : the exponential (n) value of the minimum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 0-15. : transmission opportunity, in units of 32 microseconds. Divide the desired transmission duration by 32 to determine the value to configure. For example, for a transmission duration of 3008 microseconds, enter 94 (3008/32). Range: 0-2047. : this parameter specifies mandatory admission control. With a value of, the client reserves the access category through traffic specification (TSPEC Traffic Specification. TSPEC allows an 802.11e client or a QoS-capable wireless client to signal its traffic requirements to the AP. ) signaling. A value of 0 disables this option. |
|
Voice |
Set the following parameters to define the background queue: : trbitrary inter-frame space number. Range: 1-15. : the exponential (n) value of the maximum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 1-15. : the exponential (n) value of the minimum contention window size, as expressed by 2n-1. A value of 4 computes to 24-1 = 15. Range: 0-15. : transmission opportunity, in units of 32 microseconds. Divide the desired transmission duration by 32 to determine the value to configure. For example, for a transmission duration of 3008 microseconds, enter 94 (3008/32). Range: 0-2047. : this parameter specifies mandatory admission control. With a value of , the client reserves the access category through traffic specification (TSPEC Traffic Specification. TSPEC allows an 802.11e client or a QoS-capable wireless client to signal its traffic requirements to the AP. ) signaling. A value of 0 disables this option. |
Configure EDCA Profile
The following CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. commands define an Enhanced Distributed Channel Access (EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. ) profile for APs or for clients (stations):
(host) [md] (config) #wlan edca-parameters-profile {ap|station} <profile>
(host) ^[md] (EDCA Parameters profile (AP) "default") #{background|best-effort|video|voice} [acm][aifsn <number>] [ecw-max <exponent> [ecw-min <exponent>] [txop <number>]
The following CLI Command-Line Interface. A console interface with a command line shell that allows users to execute text input as commands and convert these commands to appropriate functions. commands help to associate the EDCA Enhanced Distributed Channel Access. The EDCA function in the IEEE 802.11e Quality of Service standard supports differentiated and distributed access to wireless medium based on traffic priority and Access Category types. See WMM and WME. profile instance to a SSID Service Set Identifier. SSID is a name given to a WLAN and is used by the client to access a WLAN network. profile:
(host) [md] (config) #wlan ssid-profile <profile>
(host) ^[md] (SSID Profile "<profile>") #edca-parameters-profile {ap|sta} <profile>
