Problems with TCP transmission between two cloud cores via fiber connection

Hardware MikroTik hardware general
1

Hello everybody.

I’ve got a problem, like follows:
I’ve connected two cloud core routers via GPON fiber network. Connection lenth is 5 km. Both routers are equipped with SFP modules made by Fibrain 12,5 dBm strenth.
Bandwith test on UTP gives us result 1 Gbit TX/ 980 Mbit RX (stable during time of test 90 sec)
but
Bandwith test on TCP gives us result 180 Mbit TX/40 Mbit RX (going to 0 on RX during time of test 90 sec)

It seems that CPUs are week (Utiliztion of 5th of eight CPUs during whole TCP test equals 100%, rest - 0%). But of course it is only my observation…

I’ll be very grateful for any suggestions regarding this!

Thanks a lot!

Krzysztof

2

One process can’t be split on more cpu’s. So btest will work on only one core but I think speed should be higher anyway. TCP btest uses to much cpu power.

3

Do you think It might be caused by incompatibility of sfx stuff (fibrain) and CCR mainboard?

4

Please don’t do any bandwith testing using the device itself, it’s not made to work that way.

Best bet is to get two hosts to do iperf over the connection. That way you will see a realistic load on the CCR’s. If you need a guide on how to use iperf you can find it here.

Be sure to use multiple parallel connections to make the test more “real world”!

p.s. It’s UDP and TCP.

5

Many thanks Quindor for your remark!!!
I’ve tested it using iperf, and finally received more or less truth results: about 975 MBit/s.

Regards.

Krzysztof

6

Good to hear! 975 is definitely the absolute maximum you can push through a gigabit link so that’s working well!