Both the ISL _and_ the Dotq headers are stripped off at the trunk interface so they _both_ change the packet size but neither alters the payload.

Obviously. But the fact that ISL adds 26 bytes more than 802.1q means that multiple levels of ISL encapsulation is somewhat less practical than multiple levels of 802.1q tags. Some of us *need* those multiple levels of 802.1q tags. Steinar Haug, Nethelp consulting, sthaug@nethelp.no