1 physical layer features, 2 rate limiting, Physical layer features – Motorola Series Switch WS5100 User Manual
Page 18: Rate limiting
1-8 WS5100 Series Switch System Reference Guide
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1.2.2.1 Physical Layer Features
802.11a
• DFS Radar Avoidance – Dynamic Frequency Selection (DFS) functionality is mandatory for WLAN
equipment that is intended to operate in the frequency bands 5150 MHz to 5350 MHz and 5470 MHz to
5725 MHz when the equipment operates in the countries of EU.
The purpose of DFS is:
• Detect interference from other systems and avoid co-channeling with those systems, most notably
radar systems.
• Provide uniform loading of the spectrum across all devices.
This feature is enabled automatically when the country code indicates that DFS is required for at
least one of the frequency bands that are allowed in the country.
• TPC – Transmit Power Control (TPC) meets the regulatory requirement for maximum power and mitigation
for each channel. The TPC functionality is enabled automatically for every AP that operates on the
channel.
802.11bg
• Dual mode b/g protection – The ERP builds on the payload data rates of 1 and 2 Mbit/s that use DSSS
modulation and builds on the payload data rates of 1, 2, 5.5, and 11 Mbit/s, that use DSSS, CCK, and
optional PBCC modulations. ERP provides additional payload data rates of 6, 9, 12, 18, 24, 36, 48, and 54
Mbit/s. Of these rates, transmission and reception capability for 1, 2, 5.5, 11, 6, 12, and 24 Mbit/s data
rates is mandatory.
Two additional optional ERP-PBCC modulation modes with payload data rates of 22 and 33 Mbit/s are
defined. An ERP-PBCC station may implement 22 Mbit/s alone or 22 and 33 Mbit/s. An optional
modulation mode known as DSSS-OFDM is also incorporated with payload data rates of 6, 9, 12, 18, 24,
36, 48, and 54 Mbit/s.
• Short slot protection – The slot time is 20 µs, except an optional 9 µs slot time may be used when the
BSS consists of only ERP STAs capable of supporting this option. The optional 9 µs slot time should not
be used if the network has one or more non-ERP STAs associated. For IBSS, the Short Slot Time field is
set to 0, corresponding to a 20 µs slot time.
1.2.2.2 Rate Limiting
Rate limiting controls the maximum rate sent or received on a network. Rate limiting enables the proper
allocation of bandwidth, based on the source MAC address, destination MAC address, source IP address,