Extreme Networks Altitude 4000 Series, Справочное руководство, Страница: 265 / 521

Radio QoS Policy
Altitude
TM
4000 Series Access Point System Reference Guide
265
access point. U-APSD reduces the amount of signaling frames sent from a client to retrieve buffered
data from an access point. U-APSD also allows access points to deliver buffered data frames as
bursts ,
without backing-off between data frames. These improvements are useful for voice clients, as they
improve battery life and call quality.
The Wi-Fi alliance has created Wireless Multimedia (WMM) and WMM Power Save (WMM-PS)
certification programs to ensure interoperability between 802.11e WLAN infrastructure implementations
and wireless clients. An access point managed wireless network supports both WMM and WMM-Power
Save techniques. WMM and WMM-PS (U-APSD) are enabled by default in each WLAN profile.
Enabling WMM support on a WLAN just advertises the WLAN’s WMM capability and radio
configuration to wireless clients. The wireless clients must be also able to support WMM and use the
values correctly while accessing WLAN to benefit.
WMM includes advanced parameters (CWMin, CWMax, AIFSN and TXOP) specifing back-off duration
and inter-frame spacing when accessing the network. These parameters are relevant to both connected
access point radios and their wireless clients. Parameters impacting access point transmissions to their
clients are controlled using per radio WMM settings, while parameters used by wireless clients are
controlled by a WLAN’s WMM settings.
Access points support static QoS mechanisms per WLAN to provide prioritization of WLAN traffic
when legacy (non WMM) clients are deployed. An access point allows flexible WLAN mapping with a
static WMM access control value. When enabled on a WLAN, traffic forwarded from to a client is
prioritized and forwarded based on the WLAN’s WMM access control setting.
NOTE
Statically setting a WLAN WMM access category value only prioritizes traffic to the client.
Wireless network administrators can also assign weights to each WLAN in relation to user priority
levels. The lower the weight, the lower the priority. Use a weighted round robin technique to achieve
different QoS levels across WLANs.
Optionally rate-limit bandwidth for WLAN sessions. This form of per-user rate limiting enables
administrators to define uplink and downlink bandwidth limits for users and clients. This sets the level
of traffic a user or client can forward and receive over the WLAN. If the user or client exceeds the limit,
excessive traffic is dropped.
Rate limits can be applied externally from a RADIUS server using Vendor Specific Attributes (VSAs). Rate
limits can be applied to users authenticating using 802.1X, hotspot authentication and devices using
MAC authentication.
Configuring a Radio’s QoS Policy
“Radio QoS Policy”
To configure an access point radio’s QoS policy: