" you can see this could cause some serious problems if different VLANs are configured as the native VLAN at each end of the trunk." i still can not imaging what type of problem will occur,can you show me some examples? now i have enough switch to prove it ,this problem has confused me for days. thanks. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=18608&t=18543 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]