Rts/Cts Protocol - Cabletron Systems RoamAbout Access Point Manual

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CAUTION
There are three AP Density parameters available:
•
Low (default). The Low setting provides maximum coverage using a minimum
number of Access Points. This option is typically used for single-cell networks, but
also provides an efficient and cost effective solution for networks that include multiple
wireless clients.
•
Medium. The Medium setting can be used for environments where Access Point
stations experience slow response times even when the radio communication is
excellent.
•
High. The High setting should only be used when you are designing a wireless
infrastructure that includes a high concentration of Access Point devices.

RTS/CTS Protocol

Each device in a wireless network can sense transmissions from other devices in its network
that use the same frequency. To avoid collisions and lost data, a device only transmits when
it senses that no other device is transmitting. This behavior is referred to as the Carrier
Sense Multiple Access/Collision Avoidance (CSMA/CA) protocol. The RTS/CTS
(Request to Send/Clear to Send) protocol is useful when collisions do occur. Collisions can
occur if:
•
Two clients are unable to sense each other's transmissions and simultaneously transmit
to the Access Point.
The RTS/CTS protocol forces a wireless device to perform the following.
•
When a packet to be transmitted is shorter than the RTS/CTS threshold, the device
transmits when it senses that the medium is free. The RTS/CTS protocol is not used.
The AP Density setting must be the same for all Access Points and
wireless devices in your wireless network. Failure to do so may cause
unpredictable results for the wireless client in your network.
Using non-matching values may seriously affect the wireless
performance of the client. If Access Points are set to a High AP
Density, a client with a Low AP Density may continue to transmit to
the same Access Point instead of roaming. Meanwhile, the Access
Point ignores the client because the client's transmissions fall below
the receiver threshold. If the Access Points are set to a Low AP
Density, a client with a High AP Density may try to prematurely roam
to another Access Point.
Understanding Wireless Network Characteristics 2-7
RTS/CTS Protocol