Mimosa Backhaul Help Content
Mimosa Backhaul Performance
Copyright © 2014 Mimosa Page 30
Packet loss can occur on Ethernet between hosts and Mimosa radios due to cabling or port problems, the
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amount of which is detected and reported by most commercial routers. Packet loss can also occur on routers
due to lack of QoS policies, or in the presence of rate-limits that may be applied.
Calculating Maximum TCP Throughput (Single TCP Stream)
This formula can be used to calculate the maximum TCP throughput for a single stream given TCP Window size and
Latency:
TCP Throughput (bps) = TCP Window Size (bits) / Latency (seconds)
Example (64 KB TCP Window Size, 10 ms Latency)
Take the TCP Window Size in KB and convert to bits in Base 2 (binary):1.
64 KB * 1024 bytes/KB * 8 bits/Byte = 524288 bits
Take the latency in milliseconds and convert to seconds:2.
10 ms / 1000 ms/sec = 0.010 sec
Substitute the results from above into the original equation:3.
Throughput (bps) = 524288 bits / 0.010 seconds = 52428800 bps or 52.4 Mbps
Calculating Optimal TCP Window Size
This formula can be used to calculate the optimal TCP Window size if the MAC Throughput and the latency are
known:
TCP Window (KB) = [ MAC Throughput (Mbps) * RTT (ms) ] / 8192 bits/KB
Example (500 Mbps MAC Throughput, 10 ms latency)
(500 Mbps * 10 ms) / 8192 bits/KB = ~610 KB
Calculating Maximum Latency for a Desired Throughput
This formula can be used to calculate the maximum tolerable latency to achieve a desired throughput:
TCP Window Size (bits) / TCP Throughput (bps) = Latency (seconds)
Example (500 Mbps Throughput, 625 KB TCP Window Size)
(625 KB * 8192 bits/KB) / (500 Mbps * 1000000 bits/Mbit) = 0.0102 seconds or 10.2 ms.
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