VLAN performance

RouterOS Beginner Basics
1

Hi,
I’m rethinking my network-setup to include VLAN’s with Mikrotik devices.
My gear :
RB750Gr3 (Ros 7.10.2)
CRS326-24G2S+ (Ros 7.10.2)
I followed this tutorial : https://www.youtube.com/watch?v=YLtGQAQ8iS0 to set up the VLAN’s. The RB750 as router and the CRS326 as managed switch.
Everything works, but…
I ran an iperf3 from a server on one VLAN to a client on another VLAN and I get near wirespeed, which is OK.
But when I run iperf3 bidiectional, the bandwidth halves.
Another test : server to client on the same vlan : near wire-speed, bidirectional or not. This on the same switch.
So, I thought, the RB750Gr3 is the bottleneck. I then replaced that router by another CRS326-24G2S+ with an identical configuration and did the same tests, with the same outcome.
I’m puzzled. Am I missing something, or is this to be expected ? Is the VLAN-routing so taxing on the devices ? Is hardware-offloading not working in this case ?

Thanks for any insights.

2

Instead of watching the video (beware that there is lot of crap on YT), could you please share the config?

/export file=anynameyoulike

Remove serial and any private information (like public IP).

3

There’s nothing private, it’s a test-setup.
router.conf.rsc (3.65 KB)
switch.conf.rsc (3.33 KB)

4

Official test results (available for CRS326 and RB750Gr3) say that CRS326 is worse at routing than hEX. And realistically neither can do it at wirespeed if any kind of firewalling is involved (number under Routing → 25 ip filter rules → 512 byte packet size is pretty decent approximation to real-life routing speed, give or take). Test results are “gross numbers”, duplex iperf test over 1Gbps line wirespeed counts as 2Gbps routing throughput, which is way above capabilities of either of your devices.

CRS326 supports L3HW offloading which should allow inter-VLAN routing at wirespeed, but configuration has to be precise …