Configuration manual

128 | Configuration Reference Dell PowerConnect W-AirWave 7.4 | Configuration Guide
Background
Arbitrary Inter-frame
Space Number
7 WMM is an extension to the Carrier Sense Multiple Access with Collision Avoidance
(CSMA/CA) protocol’s Distributed Coordination Function (DCF). The collision resolution
algorithm responsible for traffic prioritization depends on the following configurable
parameters for each AC:
 arbitrary inter-frame space number (AIFSN)
 minimum and maximum contention window (CW) size
Minimum Contention
Window (Exponent)
4
Maximum Contention
Window (Exponent)
10
Transmission
Opportunity Slots in 32
μsec Units
0 Set the transmission opportunity slots in 32-micro-second intervals.
For each AC, the backoff time is the sum of the AIFSN and a random value between 0 and
the CW value. The AC with the lowest backoff time is granted the opportunity to transmit
(TXOP). Frames with the highest priority AC are more likely to get TXOP as they tend to
have the lowest backoff times (a result of having smaller AIFSN and CW parameter
values). The value of the CW varies through time as the CW doubles after each collision up
to the maximum CW. The CW is reset to the minimum value after successful transmission.
In addition, you can configure the TXOP duration for each AC.
ACM No Define whether or not admission control mandatory (ACM) is to be supported on APs
configured with this EDCA profile.
Video
Arbitrary Inter-frame
Space Number
1 WMM is an extension to the Carrier Sense Multiple Access with Collision Avoidance
(CSMA/CA) protocol’s Distributed Coordination Function (DCF). The collision resolution
algorithm responsible for traffic prioritization depends on the following configurable
parameters for each AC:
 arbitrary inter-frame space number (AIFSN)
 minimum and maximum contention window (CW) size
Minimum Contention
Window (Exponent)
3
Maximum Contention
Window (Exponent)
4
Transmission
Opportunity Slots in 32
μsec Units
94 For each AC, the backoff time is the sum of the AIFSN and a random value between 0 and
the CW value. The AC with the lowest backoff time is granted the opportunity to transmit
(TXOP). Frames with the highest priority AC are more likely to get TXOP as they tend to
have the lowest backoff times (a result of having smaller AIFSN and CW parameter
values). The value of the CW varies through time as the CW doubles after each collision up
to the maximum CW. The CW is reset to the minimum value after successful transmission.
In addition, you can configure the TXOP duration for each AC.
ACM No Define whether or not admission control mandatory (ACM) is to be supported on APs
configured with this EDCA profile.
Voice
Arbitrary Inter-frame
Space Number
1 WMM is an extension to the Carrier Sense Multiple Access with Collision Avoidance
(CSMA/CA) protocol’s Distributed Coordination Function (DCF). The collision resolution
algorithm responsible for traffic prioritization depends on the following configurable
parameters for each AC:
 arbitrary inter-frame space number (AIFSN)
 minimum and maximum contention window (CW) size
Minimum Contention
Window (Exponent)
2
Maximum Contention
Window (Exponent)
3
Table 60 Dell PowerConnect W Configuration > Profiles > SSID > EDCA AP Profile Settings (Continued)
Field Default Description