Your goal strictly should be to first isolate the issue, once the issue is isolated you can use your technical skills to fix the issue.ДЄgain, I would recommend same type of isolation and troubleshooting steps I previously recommended. Don't get caught up on technical configuration or over analyzing your network setup at this point. I highly consider you give this a though. there was only one computer on the switch, but I will try today again with no computers. I am seeing excessive broadcasts detected on some of the ports on the HP switches.Д¬onnect the mikrotik with all the server ports disabled or disconnected - does the network go down, if not connect one by one until it breaks. I suspect it to be a spanning tree issue, or other layer 2 problem when connecting the new switch. all spanning tree is disabled in the HP switches. Spanning tree is disabled on the MikroTik (should it be enabled?)Дo the HP switches have all forms of spanning tree disabled? The HP and MikroTiks have the same native v-lan. There are VLANs on the HP Switches but the non-native vlan traffic does not need to move to the MikroTik. Note: As soon as you disconnect port in questions, your ping will start to respond in step vlans in use on the HP switches? if so what is the port config between the HP and Mikrotik - are vlans enabled across this link (tagged?) do they have the same native vlan (the one untagged) and the same tagged vlans? Does the Mikrotik have Spanning tree enabled. Remember to not disconnect port from step 3. If trunk config change does not work here is what i recommend you try, see steps below.ДЎ) Put back the Mikrotik SW connection the way it was (non trunk port), Do not connect your Mikrotik sw just yet to HP SWДў) From one of the workstation/server connected to the other HP switch, launch command prompt,ДЈ) Within command prompt start continuous ping to one of the host's IP address that is connected to the Mikrotik SW, know which port this host is connected to on the Mikrotik SW for later step (ping -n 100000 your IP address)Д¤) Observe your ping response, of course you will notice packets are dropping (your Mikrotik is not connected to the HP yet).Д¦) Keep observing the ping results, if there is an issues your ping packets will start to dropД§) When your packets starts to drop, disconnecting one port at a time from Mikrotik sw to see your ping starts to respond, give it about 4 seconds or so between disconnect and re-connect ports. From what you explained it sounded like you may have a looping or back NIC card on your network.

Mikrotik switch