Evaluation and Improvement of IPv6 Stack by USAGI Project YOSHIFUJI Hideaki* , KANDA Mitsuru** , TAKAMIYA Noriaki*** and SEKIYA Yuji**** USAGI Project / WIDE Project *: The Univ. of Tokyo / **: Toshiba Corp. / *** NTT Software Corp. / ****:Keio Univ. 29th June, 2002