VeEX MTX150x Lite, User Manual

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Ethernet © VeEX Inc. All Rights Reserved. 44
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TCP Bandwidth Delay Product
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Transfer Time Ratio
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TCP Efficiency
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Buffer Delay
TCP Bandwidth Delay Product is the theoretical maximum of data that can be transmitted based on network
delay and throughput rate.
BDP (Bytes) =
Link Bandwidth (bps) x RTT (s)/8
To completely occupy the available bandwidth the Window size must be set to the BDP value.
The ideal TCP transfer time is based on the Maximum achievable TCP transfer rate, calculated based on the
Bottleneck Bandwidth (BB) and the layer 1-2-3-4 overheads associated with the network path. The actual TCP
transfer time measures the time it takes to transfer data.
Transfer Time Ratio =
Actual TCP Transfer Time / Ideal TCP Transfer Time
Example of an ideal TCP transfer time based on a 1500 Bytes size MTU and 100MB file download
TCP retransmission is done when TCP segments are lost during transmission or an acknowledgment is
missing. Segments can be retransmitted more than once.
There is no direct correlation between the number of Ethernet frames lost at the physical layer and the
number of TCP retransmission, since a single lost acknowledgment could trigger many retransmission.