I couldn’t find how to do this via the web GUI (hate the new 5400 web console – what happened to the performance graphs??) — anyhow this is the commands to do it via commandline…
5406zl-A# show vlan 200
Status and Counters – VLAN Information – Ports – VLAN 200 VLAN ID : 200 Name : VLAN200 Status : Port-based Voice : No Jumbo : No
5406zl-A# configure
5406zl-A(config)# vlan 200 jumbo
5406zl-A(config)# end
5406zl-A# sho vlan 200
Status and Counters – VLAN Information – Ports – VLAN 200 VLAN ID : 200 Name : VLAN200 Status : Port-based Voice : No Jumbo : Yes
From a windows box…
ping 10.10.9.1 -f -l 8972