WESM zl Management and Configuration Guide WT.01.XX and greater

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Wireless Local Area Networks (WLANs)
Traffic Management (QoS)
Figure 4-52. QoS Mechanisms Supported by the Wireless Edge Services zl Module
SVP
SVP maintains a high QoS specifically for VoWLAN devices that are SVP-
capable. SVP is implemented in wireless phones, wireless APs, and Spec-
traLink servers. This IEEE 802.11-compliant mechanism minimizes latency for
voice traffic by providing priority queues reserved for voice packets and by
increasing the probability that all voice packets are transmitted in a predict-
able and timely manner.
SVP devices access the medium without waiting the default 802.11 interframe
spacing (IFS) interval. In addition, SVP-enabled RPs and phones transmit
voice packets in a coordinated fashion, thereby eliminating the need for a
random backoff time and the attendant delays.