Depends on the hardware - GSR's have different MTU's than 7600's for example (and dependant on linecard too). We use 9216 between 7206VXR and 7606 for example. No, the change is immediate - "show interface" will tell you among other commands... Paul -----Original Message----- From: adrian kok [mailto:adriankok2000@yahoo.com.hk] Sent: January 30, 2009 12:57 PM To: nanog@nanog.org Subject: can I ask mtu question Hi What is max mtu in jumbo frame? ls it 9000? Do I need to reboot the switch to take effect after setting up it? if it doesn't need to reboot, How can I know the switch is running fine in this mtu 9000? eg: cisco any tools to check? Thank you for your help Send instant messages to your online friends http://uk.messenger.yahoo.com ---------------------------------------------------------------------------- "The information transmitted is intended only for the person or entity to which it is addressed and contains confidential and/or privileged material. If you received this in error, please contact the sender immediately and then destroy this transmission, including all attachments, without copying, distributing or disclosing same. Thank you."