How do I calculate the Bandwidth usage of my Lantronix product.

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Here is an example of a maximum ethernet bandwidth calculation for a serial-to-ethernet device server or console server.

For the example a baud rate of 115200 will be used. It is also assumed that it takes 10ms for the Lantronix product to send the packet onto the network.

1. Divide 1 by the baud rate, then, multiply the result by 8 to equal the number of seconds per byte.

1 divided by 115200bits/sec = (8.7 x 10^-6 sec/bit) x 8 (bits) = about 70 µsec/byte or 0.07 milliseconds per byte

2. Assuming 10ms for the Lantronix product to send data on to the network, you divide 10ms by 0.07 ms/byte. This equals the number of bytes per packet.

10ms divided by 0.07 ms/byte = about 143 bytes per packet

3. You then add 40 bytes to the number of bytes per packet to account for the TCP/IP overhead.

143 + 40 = 183 bytes/packet

4. Now multiply 183 bytes/packet by 8 to equal the number of bits per packet.

183 bytes/packet x 8 bits/byte = 1464 bits/packet

5. You then divide the number of bits/packet by 0.01 sec (10ms) to calculate the number of bits per second, thus illustrating bandwidth the Lantronix device uses.

1464bits/packet divided by 0.01sec = 146,400 bits/second of bandwidth on the network for each port running at 115,200 bps serial speed.

Note that this is the maximum bandwidth, assuming data is streaming into the serial port at 115,200bps.

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[Originally Published On: 07/09/2007 10:28 AM]