Slow TCP Speeds

RouterOS General
1

I have several routers that seem to hit a brick wall around 30 megs of TCP traffic using the bandwidth test tool between routers to test. CPU utilization never peaks above 40%. It makes no difference what type of Interface queue is being used. NAT, connection tracking, enabled or disabled seems to make no difference. The only notable difference I see is if I increase the connection count to 100 I can get the speed up to around 40-45 megs. UDP connection shows right around 100 megs each direction. Very straight forward configuration - DHCP, couple static NAT’s, no shaping, layer 7 or firewall rules.

I’ve seen this problem crop up over and over again but never any real resolution that I can find. Has anyone figured this out before? Any ideas?

2

Don’t use btest on the router itself. It is cr*p. The CPU in most routers is not suitable for all the tasks required to test TCP speeds.

If you need to do a decent test just get 2 ordinary PC’s with a modern OS like Windows 7 or better, Linux with 3.x kernel or Mac OS X 10.9 and do a bandwith test using ‘iperf’.

3

That would hold water if the CPU was spiking anywhere near the maximum but it isn’t.

4

Maybe.. still, try iperf. Routers are always better in handling traffic going through than traffic to/from the router itself.
And of course, that is what you want to know the performance of.