I have a Cisco 3850 switch with a global MTU setting of 9198. From what I've read, you can do per port mtu settings on a 3850. I had set the global mtu to 9198 since we are currently using the switch connected to a 1gbe SAN.
Can devices attached to the 3850 switch connect with the NIC set to MTU 1500 size? i have VMware hosts connected to the switch with 1500 mtu set for the data nics (pnics not connected to iscsi). They appear to be working fine for the most part but I do see slightly higher ping times to device connected to the same switch (2-8ms range).
Does the MTU size only come into effect with for devices in the same vlan? If two devices are in the same vlan but have their nics set to 1500, they should be okay correct?