I'm going to replace my core switch from C6509E to C9500-24Q. Using MS350-48FP, stack of 3, L2 config This is my test setup: Cabling: Internet -- C6509 -- MS350 -- C9500 All ports at VLAN 100 (Class C) C9500 and MS350: - 1 port (10G-SX) - No aggregation - no STP (as told be Meraki Support) As long the C6500 port is in access mode and MS350 is in access or trunk: - Connection is established (L1) - all devices are pingable - Meraki cloud is reachable (White indicator/green in dashboard) When changing the C9500 port to trunk and MS350 is in access or trunk: - Connection is established (L1) - C9500 is isolated. No ping though MS-350 - MS-350 couldn't reach the Meraki cloud (amber indicator/red in dashboard) Test also with STP, but no loop, same result. Any idea what went wrong? Regards Joerg
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