QoS in a Wireless Environment
Understanding QoS for Wireless LANs
3
Cisco 3200 Series Wireless MIC Software Configuration Guide
Precedence of QoS Settings
When you enable QoS, the WMIC queues packets based on the Layer 2 class of service value for each
packet. The WMIC applies QoS policies in this order:
1.
Packets already classified—When the WMIC receives packets from a QoS-enabled switch or router
that has already classified the packets with non-zero 802.1Q/P user_priority values, the WMIC uses
that classification and does not apply other QoS policy rules to the packets. An existing
classification takes precedence over all other policies on the WMIC.
Note
The WMIC always acts on tagged 802.1P packets that it receives over the radio interface, even
if a QoS policy has not been configured.
2.
Policies you create on the WMIC—QoS Policies that you create and apply to VLANs or to the
WMIC interfaces are second in precedence after previously classified packets.
3.
Default classification for all packets on VLAN—If you set a default classification for all packets on
a VLAN, that policy is third in the precedence list.
Using Wi-Fi Multimedia Mode
When you enable QoS, the access point uses Wi-Fi Multimedia (WMM) mode by default.
The following features of the WMM specification are supported:
•
Addition of the WMM information element to associate request frames
•
Addition of the WMM parameter element to the beacon, probe response and association response
frames
•
Addition of the QoS control field to data frames
•
Support for setting the field sent in the WMM parameter element (per access class):
–
contention window (CW) min
–
CW max
–
Aifs
–
Admission control required
–
Transmit opportunity (TXOP) size
•
Separate transmit sequence numbers for each access class and for frames that do not have the QoS
control field
•
Separate duplicate sequence number checking lists on receive for each access class and for frames
that do not have the QoS control field
•
No ACK frames for QOS control fields that do not require ACK
•
Negotiation of WMM capability with client on reassociation
•
Support for burst transmission of multiple frames in a transmit opportunity
•
Support for the WMM specified backoff procedure
•
Support for the WMM retransmit procedure
•
Addition of 802.1d priority for WMM enabled clients
Содержание 3200 Series
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Страница 120: ...Administering the WMIC Managing the System Time and Date 56 Cisco 3200 Series Wireless MIC Software Configuration Guide ...
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Страница 254: ...WIMIC Troubleshooting Error and Event Messages 12 Cisco 3200 Series Wireless MIC Software Configuration Guide ...
Страница 272: ...Supported MIBs Using FTP to Access the MIB Files 4 Cisco 3200 Series Wireless MIC Software Configuration Guide ...
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