User guide

Advanced Configuration AP-700 User Guide
Interfaces
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RTS/CTS Medium Reservation
The 802.11 standard supports optional RTS/CTS communication based on packet size. Without RTS/CTS, a sending
radio listens to see if another radio is already using the medium before transmitting a data packet. If the medium is free,
the sending radio transmits its packet. However, there is no guarantee that another radio is not transmitting a packet at
the same time, causing a collision. This typically occurs when there are hidden nodes (clients that can communicate with
the Access Point but are out of range of each other) in very large cells.
When RTS/CTS occurs, the sending radio first transmits a Request to Send (RTS) packet to confirm that the medium is
clear. When the receiving radio successfully receives the RTS packet, it transmits back a Clear to Send (CTS) packet to
the sending radio. When the sending radio receives the CTS packet, it sends the data packet to the receiving radio. The
RTS and CTS packets contain a reservation time to notify other radios (including hidden nodes) that the medium is in use
for a specified period. This helps to minimize collisions. While RTS/CTS adds overhead to the radio network, it is
particularly useful for large packets that take longer to resend after a collision occurs.
RTS/CTS Medium Reservation is an advanced parameter and supports a range between 0 and 2347 bytes. When set to
2347 (the default setting), the RTS/CTS mechanism is disabled. When set to 0, the RTS/CTS mechanism is used for all
packets. When set to a value between 0 and 2347, the Access Point uses the RTS/CTS mechanism for packets that are
the specified size or greater. You should not need to enable this parameter for most networks unless you suspect that the
wireless cell contains hidden nodes.
Wireless Service Status
The user can shut down (or resume) the wireless service on the wireless interface of the AP through the CLI, HTTP, or
SNMP interface. When the wireless service on a wireless interface is shut down, the AP will:
• Stop the AP services to wireless clients connected on that wireless interface by disassociating them
• Disable the associated BSS ports on that interface
• Disable the transmission and reception of frames on that interface
• Indicate the wireless service shutdown status of the wireless interface through LED and traps
• Enable Ethernet interface so that it can receive a wireless service resume command through CLI/HTTP/SNMP
interface
NOTE: WSS disables BSS ports.
NOTE: The wireless service cannot be shutdown on an interface where Rogue Scan is enabled.
In shutdown state, AP will not transmit and receive frames from the wireless interface and will stop transmitting periodic
beacons. Moreover, none of the frames received from the Ethernet interface will be forwarded to that wireless interface.
Wireless service on a wireless interface of the AP can be resumed through CLI/HTTP/SNMP management interface.
When wireless service on a wireless interface is resumed, the AP will:
• Enable the transmission and reception of frames on that wireless interface
• Enable the associated BSS port on that interface
• Start the AP services to wireless clients
• Indicate the wireless service resume status of the wireless interface through LED and traps
After wireless service resumes, the AP resumes beaconing, transmitting and receiving frames to/from the wireless
interface and bridging the frames between the Ethernet and the wireless interface.
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