Motorola Series Switch WS5100 - Manual (Page 24)

1-14 WS5100 Series Switch System Reference Guide
When multiple BSSID's are enabled, you cannot tell by snooping the air whether any pair of beacons is sent
out by the same physical AP or different physical AP. Hence the term "virtual AP's"- each virtual AP behaves
exactly like a single-BSSID AP.
Each BSSID supports 1 Extended Service Set Identifier (ESSID). Sixteen ESSIDs per switch are supported.
1.2.2.11 Power Save Polling
An MU uses Power Save Polling (PSP) to reduce power consumption. When an MU is in PSP mode, the switch
buffers its packets and delivers them using the DTIM interval. The PSP-Poll packet polls the AP for buffered
packets. The PSP null data frame is used by the MU to signal the current PSP state to the AP.
1.2.2.12 QoS
QoS provides the user a data traffic prioritization scheme. A QoS configuration scheme is useful in the case
of congestion from excessive traffic or different data rates and link speeds.
If there is enough bandwidth for all users and applications (unlikely because excessive bandwidth comes at
a very high cost), then applying QoS has very little value. QoS provides policy enforcement for mission-critical
applications and/or users that have critical bandwidth requirements when the switch’s total bandwidth is
shared by different users and applications.
The objective of QoS is to ensure each WLAN configured on the switch receives a fair share of the overall
bandwidth, either equally or as per the proportion configured. Packets directed towards MUs are classified
into categories such as Management, Voice and Data. Packets within each category are processed based on
the weights defined for each WLAN.
The switch supports the following QoS types:
802.11e QoS
802.11e enables real-time audio and video streams to be assigned a higher priority over regular data. The
switch supports the following 802.11e features:
• Basic WMM
• WMM Linked to 802.1p Priorities
• WMM Linked to DSCP Priorities
• Fully Configurable WMM
• Admission Control
• Unscheduled-APSD
• TSPEC Negotiation
• Block ACKQBSS Beacon Element
802.1p Support
802.1p is a standard for providing QoS in 802-based networks. 802.1p uses three bits to allow switches to
re-order packets based on priority level. 802.1p uses the Generic Attributes Registration Protocol (GARP) and
the GARP VLAN Registration Protocol (GVRP). GARP allows MUs to request membership within a multicast
domain, and GVRP lets them register to a VLAN.
Voice QoS
When switch resources are shared between a Voice over IP (VoIP) conversation and a file transfer, bandwidth
is normally exploited by the file transfer, thus reducing the quality of the conversation or even causing it to