10GBASE-T field testing requirements

10GBASE-T testing requirements are defined in TIA TSB-155.

TSB-155 is not a standard. The purpose of this Telecommunications System Bulletin is to determine the suitability of an existing category 6 cabling installation to support 10GBASE-T. If you are specifying a new installation designed to support 10GBASE-T up to 100 m (328 ft), you should be looking to the Category 6A specification.

Due to Alien Crosstalk considerations, you may not be able to run 10GBASE-T over the full length of your cabling system. You may have heard that 10GBASE-T will not run beyond 55 meters on UTP cable. TSB-155 states:

"10GBASE-T should operate over channel lengths of up to 37 meters of Category 6 cabling, and should operate over channel lengths between 37 and 55 meters of Category 6 cabling depending on the alien crosstalk environment. Channel lengths over 55 meters may require mitigation."
What this means is that no one really knows. There are so many variables in the cabling system. We have observed links as long as 60 m that meet the PS AXtalk requirements and links of 30 m which do not. The only way of knowing if a link will support 10GBASE-T is to test it for both in channel parameters such as NEXT, RL etc to 500 MHz AND for Power Sum Alien Crosstalk. TSB-155 defines the testing method for PS AXtalk.