User's Manual

l Scopia - DSCP 42
In the absence of doing anything, all of the DSCP above would map into the Video queue. To map all the traffic
into voice queue, you can use the following ACL configuration:
wlan ssid-profile VOICE
wmm-vo-dscp 46
ip access-list session VOICE
any destination [LYNC_SERVER] [LYNC_PORTS] permit tos 44 dot1p-priority 6
any destination [SCOPiA_SERVER] [SCOPIA _PORTS] permit tos 42 dot1p-priority 6
You must know the ports on which each traffic is sent so that the correct traffic is identified.
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 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 Alliance defined the Wi-Fi Multimedia (WMM) standard in response to industry requirements for
Quality of Service (QoS) support for multimedia applications for wireless networks. This is defined as per the
IEEE 802.11e standards.
WMM requires:
l the access point be Wi-Fi Certified and has WMM enabled
l the client device be Wi-Fi Certified
l the application support WMM
Enhanced Distributed Channel Access
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 802.1p priority tags, as shown in Table 193.
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
0, 3
Background Low priority traffic (file downloads, print jobs) 2, 1
Table 193: WMM Access Categories and 802.1p Tags
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:
l arbitrary inter-frame space number (AIFSN)
Dell Networking W-Series ArubaOS 6.4.x | User Guide Voice and Video | 896