PURPOSE AND SCOPE This TSB describes additional guidelines to support the IEEE 802.3an 10GBASE-T standard using installed 100 ??@ 4-pair category 6 cabling meeting the requirements of ANSI/TIA-568-C.2. This TSB characterizes the crosstalk coupling between 4-pair category 6 cabling in close proximity (referred to as alien crosstalk) and provides additional guidelines for field test equipment and field test methods and alien crosstalk mitigation. It also provides guidelines on internal parameter mitigation. These guidelines provide additional information on the extended frequency transmission performance expected of category 6 cabling from 250 MHz to 500 MHz. The transmission parameter recommendations included herein provide a means to assess installations of category 6 cabling@ as specified in ANSI/TIA-568-C.2@ up to and including 500 MHz and for the additional parameters necessary to support 10GBASE-T. This TSB does not specify any requirements for category 6 cabling systems or components@ beyond those already given in ANSI/TIA-568-C.2.