Power Save Polling - Motorola RFS7000 Series System Reference Manual

1-17
Overview
PMKs among themselves. This allows an MU to roam to an AP that it has not previously visited and reuse a
PMK from another AP to skip the 802.1x authentication.
Interswitch Layer 2 Roaming
An associated MU (connected to a particular wireless switch) can roam to another access port connected to a
different wireless switch. Both switches must be on the same L2 domain. Authentication information is not
shared between switches, nor is buffered packets on one switch transferred to the other switch.
Pre-authentication between the switch and MU allows faster roaming.
International Roaming
The switch supports international roaming per the 802.11d specification.
MU Move Command
As a value added proprietary feature between infrastructure products and MUs, a move command has been
introduced. This command permits an MU to roam between ports connected to the same switch without the
need to perform the full association and authentication defined by the 802.11 standard. The move command
is a simple packet up/packet back exchange with the access port. Verification of this feature is dependent on
its implementation in one or more MUs.
Virtual AP
The switch supports multiple Basic Service Set Identifiers (BSSIDs). An access port capable of supporting
multiple BSSID's generates multiple beacons, one per BSSID. Hence, an AP that supports 4 BSSID's can send
4 beacons. The basic requirement for supporting multiple BSSID's is multiple MAC addresses, since each
BSSID is defined by its MAC address.
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 a data traffic prioritization scheme. A QoS scheme is useful to avoid 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), 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: