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- TIA/TSB-155: Field AXT Mitigation for Installed Category 6 Cabling
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Call 1-800-626-0005 www.hubbell-premise.com N17 568-B.2-10 Category 6A ANSI/TIA-568-C.2: Category 6A UTP Cabling Augmented Category 6, or Category 6A unshielded twisted pair (UTP) cable is designed to support 10GBASE-T (10 Gigabit Ethernet) transmission in accordance with IEEE802.3an requirements. IEEE802.3an was officially ratified in June 2006. The 568B.2-10 standard for Category 6A was officially ratified in February 2008. X Category 6A permanent link and channel performance are defined to 500 MHz. X Alien Cross Talk (AXT) parameters are defined to 500 MHz. X AXT is a measure of signal coupling from energized pairs in a disturber cable or component into disturbed pairs within surrounding cables or components. X Category 6A AXT parameters are summarized below (see Glossary also): • ANEXT (Alien Near End Crosstalk). • PSANEXT (Power Sum Alien Near-End Crosstalk). • AACRF (Attenuation to Alien Crosstalk Ratio, Far End). NOTE: Previously referred to as AFEXT. • PSAACRF (Power Sum Attenuation to Alien Crosstalk ratio, Far-End). NOTE: Previously referred to as PSAFEXT. To mitigate the effects of AXT, the cable design shall meet the “worst case” 6-around-1 AXT requirements as shown below. Larger wire size, tighter twisting and thicker cable jacket are key design parameters. As a result, the cable diameter is larger, and will have an impact on installation practices. Refer to Hubbell’s “10 GbE Cabling Guidelines for more details. X Field-testing of AXT in installed links or channels is optional per 568B-2-10. X AXT field testing equipment is identified in the table on page N13. X Link and channel components must also be designed to mitigate AXT. TIA/TSB-155: Field AXT Mitigation for Installed Category 6 Cabling Telecommunications Systems Bulletin TSB-155, released in March 2007, was developed to qualify installed Category 6 cabling for operation at 500 MHz to support 10GbE transmission. Category 6 cabling used for 10GbE applications is restricted to the performance level of the cable and the AXT environment. X Defines field AXT test parameters for installed Category 6 cabling links. X Establishes length restrictions for installed Category 6 cabling. X Standard Category 6 cabling: 37 meters maximum (no testing). X Standard Category 6 cabling: 37 to 55 meters maximum (AXT testing recommended, mitigation not likely). X Enhanced Category 6 cabling: > 55 meters (Mitigation and AXT testing highly recommended, , mitigation expected). X NOTE: The primary limitation with 10GbE operation is ANEXT. Individual Cat 6 links with no EMI should be able to support 10GbE up to 100m. Multiple links in parallel become a concern with ANEXT. The mitigation procedure suggested by TSB-155 is outlined below. Each mitigation step requires field AXT testing to 500 MHz for verification. X Unbundle cables and patch cords. X Substitute ScTP patch cords and equipment cords. X Substitute Category 6A jacks. X Substitute Category 6A panels. "Worst Case" 6 around 1 AXT Test Configuration. |