Jumbo frames need to be enabled globally, not on a specific port or ports. 


Use the following commands to enable Jumbo frames on the switch. 


awplus# configure terminal

awplus(config)# platform jumboframe


It will give you this message % Save the config and restart the system for this change to take effect.                                                                                                                                          


To save the configuration before restart do this:


awplus(config)#end

awplus#wr

awplus# reboot


Then say yes to reboot. 


Here is Allied’s Command Reference for AlliedWare Plus Version 5.5.4-2.x: https://www.alliedtelesis.com/sites/default/files/file/2025-05/x530_Command_Ref_554-2.pdf