by Patrick McLaughlin
In December we reported on some of the initial efforts by the Telecommunications Industry Association (TIA) to produce a set of Category 8 twisted-pair cabling specifications for the support of 40GBase-T (see “TIA working on Category 8 standard,” December 2012). The TIA group working on the Category 8 specifications has ambitious plans concerning the amount of progress it expects to make in 2013.
If you are inclined to read and/or contribute to industry-related discussion groups, you may already have seen some of the technopolitical debates taking shape around the Category 8 specifications. In large part these debates concern the TIA’s decision to move ahead with a Category 8 specification independent of the ISO/IEC’s Category 7 and 7A specifications, and the likelihood that the Category 8 requirements for some electrical-performance characteristics will be less-strict than those of Category 7A for the same characteristics. We mentioned this in our December reporting as well, but as you might imagine the topic has taken on a life of its own in the aforementioned discussion groups.
For me there is a bottom line to the discussion/debate. It’s the bottom line for me because it’s what I honestly believe matters the most to you as readers of this publication. And that is: Will a cabling system that complies with the specifications support the intended application? In this case, it’s: Will a Category 8-compliant system support 40GBase-T?
The development of Category 8 is in keeping with the successful efforts through which a set of cabling-performance parameters is developed in tandem with an Ethernet transmission protocol. By contrast and for example, the TIA’s development of Category 6 was not in sync with an IEEE effort to develop 1000Base-TX (i.e. Gigabit Ethernet over two copper pairs). The IEEE passed on a 1000Base-TX project and the TIA’s own efforts to put forth 1000Base-TX fell flat. Category 6A, on the other hand, aligned that cabling-performance level with 10GBase-T.
No one has ever told me that the TIA passed on opportunities to construct a Category 7 or 7A set of specifications because there was no direct alignment with an Ethernet protocol. But the TIA’s actions, in the form of its decision to move forth with a 40GBase-T-aligned Category 8, make a statement.
The issue of Category 8’s backward-compatibility with Category 7A remains unsolved as of today. Look for upates here, and in those juicy discussion forums, in the months ahead. ::