User Manual

56 MDS entraNET 900 System Guide (Preliminary) MDS 05-4055A01, Rev. A
• 20 bytes—802.11 RTS.
• 14 bytes—802.11 CTS.
• 66 bytes—Total Over-the-air bytes for RTS/CTS with PHY
headers.
If the frame is TCP, then there is a 32-byte TCP header instead of the
8-byte UDP header.
• ARP requests, ARP replies and BPDU’s will affect throughput.
• ARP requests are 60-byte Ethernet frames. 142 bytes
over-the-air.
• ARP replies are 60-byte Ethernet frames. 142 bytes
over-the-air.
• BPDUs are 60-byte Ethernet frames. 142 bytes over-the-air.
Note that the overhead to put a single Ethernet frame
over-the-air is 82 bytes. If RTS/CTS is invoked, it is 148 bytes.
Therefore, the overhead for a minimal Ethernet frame
(60 bytes) is 128% and, as such, gives the transceiver a poor
small-packet performance.
If any transceiver in your entraNET network is connected to a large
LAN, such as may be found in a large office complex, there may be
undesired multicast/broadcast traffic over the air.
4. Station-to-Station Traffic
• When sending frames from an endpoint connected to one trans-
ceiver to another endpoint with a different transceiver, the
throughput will be halved at best. This is because all frames
must go through the AP. Therefore, in the previous 100-byte
UDP example, the number of over-the-air bytes will be 380
bytes (190 bytes x 2) if the frame has to go station-to-station.
5. Interference has a direct correlation to throughput.
• Interference could be caused by any unnecessary traffic on the
network from unrelated activities, or Radio Frequency Interfer-
ence in the wireless spectrum.
Tips for Optimizing Network Performance
Here are some suggestion on things to try that may maximize
throughput:
1. AP Only: Increment the
Dwell Time to the maximum of 262.1 ms.
This lowers the overhead since it will stay longer on a channel. The
down side is that if a particular channel is interfered with it will take
longer to hop to another channel.
(
Main Menu>Radio Configuration>Dwell Time)