The mistake most users make when conducting a speed test on MikroTik is to do a speed test from the device in question. There is a more accurate way of doing this!
What is the Bandwidth Tester used for?
The Bandwidth Tester can be used to measure the throughput to another MikroTik router (either wired or wireless) and thereby help to discover network bottlenecks.
How does the Bandwidth Tester work?
The Transmission Control Protocol (TCP) test uses the standard TCP protocol with acknowledgments and follows the TCP algorithm on how many packets to send according to latency, dropped packets, and other features in the TCP algorithm. Please review the TCP protocol for details on its internal speed settings and how to analyse its behaviour. Statistics for throughput are calculated using the entire size of the TCP data stream. As acknowledgments are an internal working of TCP, their size and usage of the link are not included in the throughput statistics. Therefore this statistic is not as reliable as the User Datagram Protocol (UDP) statistic when estimating raw throughput, but rather gives a true reflection of available usable bandwidth.
The UDP tester sends 110% or more packets than currently reported as received on the other side of the link. To see the maximum throughput of a link, the packet size should be set for the Maximum Transmission Unit (MTU) allowed by the links (which is usually 1500 bytes). There is no acknowledgement required by UDP; this implementation means that the closest approximation of the throughput can be seen.
How to conduct the bandwidth test:
Conducting a bandwidth test utilises a larger amount of processing power, making it difficult to determine the real capacity of a router. To eliminate the possibility of an inaccurate reading from the bandwidth test, it is important to use two devices/routers in-line with the tested router. The one will serve as the bandwidth test server, which is connected in-line with the tested router and the other will act as the bandwidth client.
If you use the UDP protocol the Bandwidth Test counts IP header+UDP header+UDP data. If you use TCP the bandwidth test counts only TCP data (TCP header and IP header are not included).