ZyXEL Communications ZyWall USG 50-H Series, User Manual

Page: 185 / 704

Chapter 8 Interface
ZyWALL USG 50-H User’s Guide
185
Super Mode Select this to improve data throughput on the WLAN by enabling fast frame and
packet bursting.
CTS/RTS
Threshold Use CTS/RTS to reduce data collisions on the wireless network if you have wireless
clients that are associated with the same AP but out of range of one another. When
enabled, a wireless client sends an RTS (Request To Send) and then waits for a CTS
(Clear To Send) before it transmits. This stops wireless clients from transmitting
packets at the same time (and causing data collisions).
A wireless client sends an RTS for all packets larger than the number (of bytes) that
you enter here. Set the RTS/CTS equal to or higher than the fragmentation threshold
to turn RTS/CTS off.
Fragmentation
Threshold This is the threshold (number of bytes) for the fragmentation boundary for directed
messages. It is the maximum data fragment size that can be sent.
Output Power Set the output power of the ZyWALL in this field. If there is a high density of APs in
the area, decrease the output power of the ZyWALL to reduce interference with other
APs. Select one of the following
100% , 50% , 25% , 12.5% or Minimum . See the
product specifications for more information on your ZyWALL’s output power.
802.11n
Settings
Channel Width Select 20MHz to use a single radio channel.
Select 20/40MHz (Auto) to bond two adjacent radio channels (also known as
channel-bonding mode). This can increase throughput when there is a strong signal,
although it is often better to use the default 20 MHz setting in a location where the
environment hinders the wireless signal.
Aggregation
MSDU (A-
MSDU) Select this to bundle small groups of data (MAC Service Data Units, or MSDU) into
larger units of MSDUs called Aggregate MSDUs (A-MSDU). The resulting larger
MAC frames mean fewer frame headers and gaps between frames to deal with. This
can improve the efficiency of traffic types that send many frames to the same
destination (like voice and video for example).
Auto Block
ACK For reliability, IEEE 802.11 a/b/g systems have receiving stations send a separate
acknowledgment (ACK frame) to the transmitting station for each frame received. A
transmitter that does not receive the ACK retransmits the frame until it receives an
ACK. This is also used in rate adaptation where the transmitter uses a lower data
rate if there are too many retransmissions.
IEEE 802.11 n enhances the MAC layer efficiency by allowing the ZyWALL to
automatically group the acknowledgement frames for several received frames into a
single block ACK frame.
Guard Interval The guard interval refers to the wait time between the transmissions of data bits to
make sure the bit transmissions do not interfere with each other. The short guard
interval increases data transfer rates but also increases interference. The long guard
interval reduces data transfer rates but also reduces interference.
Interface
Summary
# This field is a sequential value, and it is not associated with any interface.
Name This field displays the name of the WLAN interface.
SSID This is the SSID (Service Set IDentity) of the WLAN interface.
IP Address This field displays the current IP address of the WLAN interface. If the IP address is
0.0.0.0, the interface does not have an IP address yet.
This screen also shows whether the IP address is a static IP address (
STATIC ) or
dynamically assigned ( DHCP ). IP addresses are always static in virtual interfaces.
Mask This field displays the interface’s subnet mask in dot decimal notation.
Security This field displays what type of security the WLAN interface uses.
Table 58 Network > Interface > WLAN
LABEL DESCRIPTION