Mikrotik LACP with Fortigate configuration for redundancy

RouterOS General
1

Hi,

I have a setup to make with the most redondant link has possible. This is a mix with 1 Fortigate 200E running 7.0.x, 2x Mikrotik CRS518 v7.11.2 has Cores, 2x CRS354-48P PoE for VoIP and 3x FortiSwitch 148F for PC distribution. The main link to Cores are 2x 1G per Core switch to Fortigate. I’m using MLAG ID 10 to use both cores in the same Fortigate lcap trunk.

When we first setup all switches it was stable, but it changed when we add servers to the core switches. ping lost was occurring. I think lacp renegotiation or STP starts to play with us.

Any advise how to achieve this setup has redundant has possible or diagnose what is causing the ping lost?

Network plan attached.
Plan des switch (pour support Mikrotik).jpg

MAC address jumping around on MLAG interfaces (Bridge Hosts table)
2

Any toughts about this someone?

3

Hello! I am having the exact same setup with a Fortigate 80F, 4 * CRS326-24S+2Q+ and 2 * Fortiswitch 148F.

Did you manage to solve the problem?
Also, can you help with some configuration outputs from Mikrotik and Fortigate side?

4

Could be mac-address table issue on the MikroTik side of things, given MLAG. Although, this is just me assuming - no proof.