So I have read that 3750 (all gigE ports) switch can be configured for Jumbo frames globally only, but that you can configure this for L3 or L2 or both. My question pertains to running an L2-only Vlan in Jumbo mode (mtu=9000), but I still want the ability to run another L2/L3 Vlan in standard frame size mode (mtu=~1512). I will configure only L2 jumbo frame support with the following command:
system mtu jumbo 9000 (and reboot)
Now all jumbo hosts will be on a L2-only vlan in the 3750 stack, and communicate w/ 9000 bytes frames.
On another Vlan in the same switch stack, I will only have 1512 MTU hosts. Since MTU should be a flexible parameter, is it correct to assume the 9000 MTU ports will step down for all connected 1512 MTU hosts, and allow them to communicate to themselves as well?
This would in effect make the switch capable for running both regular/jumbo frame in a dual mode. I am not concerned at this point with routing between the two disparate-sized Vlans.