Cisco RV180, Руководство администратора

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Configuring the Wireless Network (Cisco RV180W)
Configuring Advanced Wireless Settings
Cisco RV180/RV180W Administration Guide 70
3
Configuring Advanced Wireless Settings
To configure advanced wireless settings on the Cisco RV180W:
STEP 1
Choose Wireless > Advanced Settings.
STEP 2
In the Beacon Interval field, enter the time in milliseconds between beacon
transmissions. The default interval is 100 milliseconds.
STEP 3
In the DTIM Interval field, enter the interval at which the delivery traffic indication
message should be sent. A DTIM field is a countdown field informing clients of the
next window for listening to broadcast and multicast messages. When the Cisco
RV180W has buffered broadcast or multicast messages for associated clients, it
sends the next DTIM with a DTIM Interval value. Its clients hear the beacons and
awaken to receive the broadcast and multicast messages.The default interval is 2
beacon intervals.
STEP 4
The Request to Send (RTS) Threshold is the packet size, in bytes, that requires the
AP to check the transmitting frames to determine if an RTS/Clear to Send (CTS)
handshake is required with the receiving client. Using a small value causes RTS
packets to be sent more often, consuming more of the available bandwidth,
reducing the apparent throughput of the network packets. The default value is
2346, which effectively disables RTS.
STEP 5
The Fragmentation Threshold is the maximum length of the frame, in bytes,
beyond which packets must be fragmented into two or more frames. Collisions
occur more often for long frames because while sending them, they occupy the
channel for a longer time. The default value is 2346, which effectively disables
fragmentation. If you experience a high packet error rate, you can slightly increase
the fragmentation threshold; setting the fragmentation threshold too low may
result in poor network performance. Only minor reduction of the default value is
recommended.
STEP 6
Choose the Preamble Mode. The 802.11b standard requires that a preamble be
appended to every frame before it is transmitted through the air. The preamble
may be either the traditional “long” preamble, which requires 192
μ s for
transmission, or it may be an optional “short” preamble that requires only 96 μ s. A
long preamble is needed for compatibility with the legacy 802.11 systems
operating at 1 and 2 Mbps. The default selection is long.
STEP 7
Choose the Protection Mode. Select none (the default) to turn off CTS. The CTS-
to-Self Protection option enables the CTS-to-Self protection mechanism, which is
used to minimize collisions among stations in a mixed 802.11b and 802.11g
environment. This function boosts the Cisco RV180W’s ability to catch all wireless
transmissions but severely decreases performance.