Need recommendations on how to fix an issue with looping or flooding, likely due to 2 Ethernet Bridges on the same network.
On a network we are currently setting up, we have a Cisco switch, 2 Extreme switches, and a Sophos UTM Ethernet Bridge (2 ports on a UTM are bridged together, essentially creating another 2-port switch inside the UTM).
Cisco switch is the 'old network' and currently unplugged from the Extreme switches (the 'new network'). But plugging this into the 'new network' caused us to notice the amplification issues.
The 2 extreme switches are setup independently. Not stacked.
They have 1 cable connecting the two Extreme switches together.
The 2-port bridge on the UTM has 1 port connected to Extreme1, and other port connected to Extreme2.
With this setup, the lights on both Extreme switches show constant activity. Unplugging 1 of the 2 ports from the UTM seems to 'fix' the issue. Also, as mentioned previously, with this setup also plugged into the Cisco 'old network', the lights on the Cisco showed constant activity and network issues occurred.
It seems like a possibly logical 'fix' would be to just use the UTM bridge to connect the two Extreme switches together (eliminating the cable connecting the 2 Extreme together). The issue here though, is the UTM ports are 1Gb speed, whereas the Extreme switches are 10Gb.
If we did this, the hardware connected between the two switches would be limited to 1Gb speed. This also brings up a side question, which is with the current setup, how is the speed to use determined.. or how does it know which path to use? Can we force 10Gb speeds somehow (bypassing the 1Gb UTM ports unless going to something on the UTM)?