Hello. No, There are no another links between any switches/stacks (except of stack cables on switch stacks). All ethernet and sfp ports configured with rstp enabled and stp is checked as loop guard. Strange thing is if I connect every stack per router (4 + 4 links total), network goes down. And if I disconnect physically one of the links (exactly ANY of the links, on any router) - it works fine. I think, the trouble is in vrrp anyway (but direct vrrp ethernet link is disconnected, vrrp vlan is present and all the connection (mx-ms stacks) links are configured to allow all vlans, as trunks, dropping untagged traffic. vrrp vlan is configured with /30 subnet mask). ... View more

So, it seems to be OK, but when I insert the last switch stack (fourth), my network is going down. Four switch stacks are inserted in 19,20,21,22 master router ports Three switch stacks are inserted in 19,20,21 spare router ports. Forks fine until I insert fourth switch stack in the spare router. Router ports are configured to Trunk, no native vlan, drop untagged traffic. Switch ports are configured with the RSTP enabled and STP guard disabled.     ... View more

Hi, thanks for your reply! I`ll try to remove ethernet for vrrp, seems like a working suggestion! ... View more

Hello, thank you for your reply. It`s the switch stacks, as I described above. ... View more