Mikrotik CCR1072 VRRP + STP packet loss

Hi!

I have two CCR1072 routers and five core switches (not Mikrotik) with VRRP, STP and one BGP peer with full BGP table and a secondary BGP peer with a default route only.

The vrrp settings are the same on the two routers:
bridge(sfp+4, sfp+5) ----> vrrp interface -----> ~ 80 different vlans(+IP interfaces for the vlans)
The master CCR is the root bridge (p=0x1000) and the backup ccr has the second lowest priority (0x2000).
Each router connects to 2-2 core switches. (R1 sfp+4—> SW1 port 27 || R1 sfp+5 —> SW4 port 27) (R2 sfp+4 —> SW1 port 28 ||R2 sfp+5 —> SW4 port 28).

Everything works well:
-The failover between BGP peers.
-The failover between VRRP CCRs.
-The failover over STP bridges.

I have only one problem:
The packet loss is between 0,3% and 2,5% from the client (e.g. a server) to the vrrp master router. There isn’t any packet loss from the vrrp master to the internet (e.g. 8.8.8.:sunglasses:.
I have checked the interface counters and noticed that there were large amount of TX Drops on vlan interfaces. The cpu load is between 6 and 12% and the traffic is between 0,8 and 1,3 Gb/s on master.

I have disabled the firewall filters and there aren’t any nat/mangle/simple queue/queue tree settings but the packet loss is still present.

Does anyone have any idea what causes the TX drops and packet loss?

Regards
Adam

I faced the same issue.
My core stack is Huawei and it has ARP port defend enabled by default, as VRRP and LACP generates a lot of ARP requests, default thresholds got exceeded and interface rate limit was applied, it repeated very often, about once a minute or less. Then I disabled that ARP defend on all interfaces to gateway and the problem resolved.