User's Manual

246 Operation
Chapter 5 - Command Line Interface
Syntax
wmm-acknowledge-policy <ac_number> <ack | noack>
• ac_number - Access categories. (Range: 0-3)
• ack - Require the sender to wait for an acknowledgement from the receiver.
• noack - Does not require the sender to wait for an acknowledgement from the receiver.
Default
ack
Command Mode
Interface Configuration (Wireless)
Command Usage
• WMM defines four access categories (ACs) – voice, video, best effort, and background. These
categories correspond to traffic priority levels and are mapped to IEEE 802.1D priority tags (see
Table 4-5). The direct mapping of the four ACs to 802.1D priorities is specifically intended to
facilitate interpretability with other wired network QoS policies. While the four ACs are specified
for specific types of traffic, WMM allows the priority levels to be configured to match any
network-wide QoS policy. WMM also specifies a protocol that APs can use to communicate the
configured traffic priority levels to QoS-enabled wireless clients.
• Although turning off the requirement for the sender to wait for an acknowledgement can increases
data throughput, it can also result in a high number of errors when traffic levels are heavy.
Example
5.24.3 wmmparam
This command configures detailed WMM parameters that apply to the AP (AP) or
the wireless clients (BSS).
Syntax
wmmparam <AP | BSS> <ac_number> <LogCwMin> <LogCwMax> <AIFS> <TxOpLimit>
<admission_control>
• AP - Access Point
• BSS - Wireless client
• ac_number - Access categories (ACs) – voice, video, best effort, and background. These
categories correspond to traffic priority levels and are mapped to IEEE 802.1D priority tags as
shown in
Table 4-5. (Range: 0-3)
• LogCwMin - Minimum log value of the contention window. This is the initial upper limit of the
random backoff wait time before wireless medium access can be attempted. The initial wait time
is a random value between zero and the LogCwMin value. Specify the LogCwMin value. Note that
the LogCwMin value must be equal or less than the LogCwMax value.
(Range: 1-15 microseconds)
• LogCwMax - Maximum log value of the contention window. This is the maximum upper limit of
the random backoff wait time before wireless medium access can be attempted. The contention
window is doubled after each detected collision up to the LogCwMax value. Note that the CWMax
value must be greater or equal to the LogCwMin value. (Range: 1-15 microseconds)
• AIFS - Arbitrary InterFrame Space specifies the minimum amount of wait time before the next
data transmission attempt. (Range: 1-15 microseconds)
• TXOPLimit - Transmission Opportunity Limit specifies the maximum time an AC transmit queue
has access to the wireless medium. When an AC queue is granted a transmit opportunity, it can
transmit data for a time up to the TxOpLimit. This data bursting greatly improves the efficiency for
Enterprise AP(if-wireless g)#wmm-acknowledge-policy 0 noack
Enterprise AP(if-wireless g)#