LAN and WAN Traffic Gap (~600 Mbps difference) on MikroTik x86

RouterOS General
1

Hello,

I am facing a traffic reporting issue on my MikroTik router.

Total capacity: 3,800 Mbps (from 3 upstreams on VLANs)

NIC: Intel X520 10G

Cabling: 10G sfps for both WAN and LAN on the X520 card

WAN: Coming from a Grandstream switch

LAN: Going to a Huawei OLT

Users: Around 2,200 active PPPoE users

The problem is that the WAN interface shows ~600 Mbps more traffic (total 3800mbps) than the LAN interface (upstream vlans choked at total 3800 but lan is not showing full bandwidth). Both ports of the Intel X520 are being used (one as WAN, one as LAN).

PXL_20250903_144159212
PXL_20250903_1441592121920×1080 181 KB

PXL_20250903_144155666
PXL_20250903_1441556661920×1080 211 KB

I want to understand what could be causing this 600 Mbps gap between WAN and LAN statistics. Is it related to VLAN overhead, PPPoE encapsulation, or something else?

Has anyone else experienced a similar gap with Intel X520 NICs in high-traffic PPPoE environments?

Thanks for any insights.

2

1'st , identify any traffic that is going to your WAN IP address/network.
2'nd , torch the WAN and sort multiple ways.
3'rd , If the WAN is live IP addresses and the LAN is a RFC-1918 natted network , check if you have and RFC-1918 traffic leaving or entering the WAN interface. ( Example - WAN a.b.c.d/e LAN 192.168.0.1/24 , if/when a LAN connected computer tries to connect to 192.168.11.11 , is that traffic going out the WAN port ?

3

There is no RFC-1918 traffic leaving or entering the WAN interface.
Can you please guide me on queues> interface queue type for my physical interfaces. This can be problem