Joe Touch wrote: > Reason #1: IP reassembly is already deployed. The reality is that wise operators denied deployment of stupid idea of extension headers including that for IP reassembly. > - now you want that info even further obscured by another > layer of encapsulation Wrong. The worst kind of obscurity is a transport header at the end of a chain of 1000 or more IPv6 extension headers. Note that the transport header may not be placed in the first fragment. As following a long chain means vulnerability to DOS, there should be some upper bound on the chain length and the most reasonable value for the upper bound is 0, because all the extension headers are useless. Masataka Ohta