VLAN & CPU load on CRS-112-8G-4S-IN

I want to accomplish the attached network design. I’ve configured VLANs under

/interface ethernet vlan

and created bridges to create TRUNKs. The network works as expected. But the issue is even with 100Mbps traffic the CPU load on CRS112-8G-4S-IN reaches 100% which I’m not expecting.

Just to make clear I was right. I flushed all the config on one of the switches, simply created a bridge of 2 interfaces and tried transferring data through it, the result was same.

But, when I created one port slave, though I don’t know much about that, to the another the CPU load was reduced to ~10% on same traffic of ~100Mbps. But then I don’t know how to, or if I could at all, create VLANs on slave interfaces. I’ve never used switch feature of RouterOS and am a novice when it comes to VLANs.

If someone could help with it will be very much appreciated.

Thank you,

Rahul.
network-diagram - Copy.png

You need to configure the switch for vlans instead of using cpu bridging.

http://wiki.mikrotik.com/wiki/Manual:CRS_features
http://wiki.mikrotik.com/wiki/Manual:CRS_examples

Keep in mind that if you need, just connection tracking enabled, this router is able to process just 2.5 kpps.
Differently from other CRS models you could use it just as a switch.

http://forum.mikrotik.com/t/crs112-8g-4s-routing-power-far-below-specs-unusable/103733/1