network throughput calculation from data

At the end of simulation I have the packet sent number as well as packets lost. Is it correct determine the throughput in this way?

thr = packet_sent/total_data

with total_data = packet_sent+packet_lost

Answer 1

[Walter Roberson]

Not under the usual definition of "network throughput". The usual definition of "network throughput" would be the total number of bytes successfully received, divided by the total time over which the transmission is being attempted. Some definitions of "network throughput" would include the size of all packet headers and trailers in the number of bytes successfully received (the "raw" throughput"), and other definitions of "network throughput" would count only the bytes of "payload" after removing all error detection and error correction schemes (the "cooked" throughput, though "cooked" is a term not often heard now.)

[Roberto]

If a node receive a packet of 1500 byte, this packet is transmitted during 5 slot, and each slot is 1 ms, the throughput is 1500byte/5*1ms. If the total number of packets successfully received is 20 for example, the total throughput is 20*(1500/5*1ms). Right?

[Walter Roberson]

20 packets might have been successfully received, but you haven't given us enough information to know how much time was consumed. (20 packets times 1 ms/slot times 5 slots) gives the minimum transmission time, but the 20 received might have been out of 37 attempted (for example). So the calculation might run like

(1500 bytes/packet * 20 packets delivered) /
(1 ms/slot * 5 slots/packet * 37 packets)

which would be 30000 bytes in 185 ms (0.185 seconds), which would work out as 162162 bytes/second. Usually you would then convert to bits per second.

Answer 2

[Roberto]

Can I calculate throughput in the way I suggest in the comment?

[Nsee longe]

Thank you for the good attempt but, I would like to know where do you use channel bit rate?, eg 11Mbps, 54Mbps etc to calculate throughput

[Walter Roberson]

Some protocols are defined strictly in terms of bits, rather than in terms of time. In such cases, when you know the total number of bits including all overhead and mandatory gaps, then you can divide the number of bits by the bit rate to get the time requirement.

However, your mention of 11 Mbps and 54 Mbps are rates associated with 802.11* wireless protocols. The faster rate protocols send multiple bits simultaneously at different transmission rates, making it difficult to calculate the exact time requirements for packets of intermediate sizes.

802.11g is 54 Mbit/s raw, but only 31.4 Mbit/s net throughput.

Note that especially for backwards compatibility reasons, part of wireless protocols are defined in terms of time rather than in terms of bits.