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Posts: 10
Joined: Thu Aug 01, 2019 8:20 pm

CRS112 with VLANs slow performance 100% CPU

Thu Aug 01, 2019 9:14 pm

I configured VLANs as described here: ... s_examples

It is very simple config:
- ether2,3 VLAN11 subnet
- ether3,4 VLAN22 subnet

Looks like everything is working fine I got correct IP from DHCP and connection is OK but performance is quite bad.

When I tried copy file from one PC to another on default configuration speed was around 110 MB/s and CPU was fine after I added VLANs and connected 2 PC to the same VLAN (ether2,3) and tried copy same file I got 40 MB/s and CPU utilization was 100%

As both PC are in same VLAN / subnet why are packet processed by CPU ? I can understand when I start copy between VLANs then packets should be processed by CPU as routing is required.

Could you please check my configuration. May be I did something wrong.

Really appreciate you help ...

Link to my notes from learning and doing configuration: ... wUeP0td4vP_

My configuration:
/interface bridge
add name=bridge protocol-mode=none
/interface vlan
add comment=familly1 interface=bridge name=VLAN11 vlan-id=11
add comment=familly2 interface=bridge name=VLAN22 vlan-id=22
/interface ethernet switch
set drop-if-invalid-or-src-port-not-member-of-vlan-on-ports=ether1,ether2,ether3,ether4
/ip pool
add name=familly1 ranges=
add name=familly2 ranges=
/ip dhcp-server
add address-pool=familly1 disabled=no interface=VLAN11 name=familly1
add address-pool=familly2 disabled=no interface=VLAN22 name=familly2
/interface bridge port
add bridge=bridge interface=ether2
add bridge=bridge interface=ether3
add bridge=bridge interface=ether4
add bridge=bridge interface=ether5
/interface ethernet switch egress-vlan-tag
add tagged-ports=switch1-cpu vlan-id=11
add tagged-ports=switch1-cpu vlan-id=12
/interface ethernet switch ingress-vlan-translation
add comment=familly1 customer-vid=0 new-customer-vid=11 ports=ether2,ether3
add comment=familly2 customer-vid=0 new-customer-vid=22 ports=ether4,ether5
/interface ethernet switch vlan
add comment=familly1 ports=switch1-cpu,ether2,ether3 vlan-id=11
add comment=familly2 ports=switch1-cpu,ether4,ether5 vlan-id=22
/ip address
add address= comment=WAN interface=ether1 network=
add address= comment=familly1 interface=VLAN11 network=
add address= comment=familly2 interface=VLAN22 network=
/ip dhcp-server network
add address= dns-server= gateway=
add address= dns-server= gateway=

Thanks and regards,
just joined
Topic Author
Posts: 10
Joined: Thu Aug 01, 2019 8:20 pm

Re: CRS112 with VLANs slow performance 100% CPU  [SOLVED]

Mon Aug 05, 2019 12:20 pm

after some investigation I found some left static routes added to the testing computers which caused improper routing. After remove those everything started working as should. Transfer speed within VLANs 110 MB/s, transfer speed between VLANs 30 MB/s

so at the end no Mikrotik issue but my fault :-(

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