AirWave Wireless Management Suite | Configuration Guide Aruba Configuration Reference | 131
3. Click Add or Save. The added or edited profile appears on the Profiles > SSID page.
Profiles > SSID > EDCA AP
Wireless Multimedia (WMM) provides media access prioritization through Enhanced Distributed Channel
Access (EDCA). EDCA defines four access categories (ACs) to prioritize traffic: voice, video, best effort,
and background. These ACs correspond to 802.1d priority tags, as shown in Table 49.
While the WMM 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, applications assign data
packets to an AC. In the client, the data packets are then added to one of the transmit queues for voice,
video, best effort, or background.
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:
z arbitrary inter-frame space number (AIFSN)
z minimum and maximum contention window (CW) size
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. On the controller, you configure the AC
priorities in the WLAN EDCA parameters profile. There are two sets of EDCA profiles you can configure:
z AP parameters affect traffic from the AP to the client
z STA parameters affect traffic from the client to the AP
Perform these steps to create or edit EDCA AP profiles.
BC/MC Rate
Optimization
No Enables or disables scanning of all active stations currently associated to a mesh
point to select the lowest transmission rate based on the slowest connected mesh
child. When enabled, this setting dynamically adjusts the multicast rate to that of the
slowest connected mesh child. Multicast frames are not sent if there are no mesh
children.
NOTE: Aruba recommends using the default value.
Strict Spectra-
link Voice
Protocol (SVP)
No Use this setting for Spectralink VoIP devices. This setting automatically permits and
prioritizes the Spectralink Voice Protocol (SVP).
Table 49 WMM Access Categories and 802.1d Tags
WMM Access Category Description 802.1d 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
0, 3
Background Low priority traffic (file downloads, print jobs) 2, 1
Table 48 Aruba Configuration > Profiles > EDCA AP Profile Settings (Continued)
Field Default Description
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