Choosing the right cabling has never been more important, or more complex and so it’s useful to understand the options we now face, particularly in light of unfolding category 8 developments.There are multiple standards bodies that specify cabling standards e.g. TIA (Telecommunications Standards Organization), ISO (International Standards Organisation) and CENELEC (European Committee for Electrotechnical Standardization), but here we will concentrate on ISO/IEC and TIA.The 10GBASE-T standard specifies 10Gb/s transmission rates and is the fastest commercially available Ethernet over copper balanced twisted-pair cabling application. Category 5e is not capable of supporting 10Gb/s and is not recognised in the 10GBASE-T standard. ISO/IEC and TIA guidelines specifically recommend against installing new class E/category 6 cabling to support 10GBASE T.So, the cabling choices for new installations supporting 10GBASE-T over full channel topologies up to 100 metres are limited to class EA/category 6A, class F/category 7, or class FA/category 7A. For new data centres, ISO and other standards bodies have specified the minimum grade of cabling to be deployed in new data centres to be class EA/category 6A. The IEEE 802.3 40GBASE-T Task Force has nearly finalized baseline objectives for a new 40 Gb/s balanced copper twisted-pair Ethernet application standard and is currently working on developing a first draft. This means that the longer term view should encompass 40 Gb/s Ethernet speeds, which takes us well beyond the capacity of class EA/category 6A cabling.Traditionally, cabling categories are supersets of each other – meaning that a higher category of cabling meets or exceeds all of the electrical and mechanical requirements of a lower category of cabling and is also backwards compatible with the lower performing category. Whilst the TIA specifies cabling systems up to category 6A performance, it chose not to adopt category 7 or 7A as published by ISO/IEC. Instead, the TIA has decided to call its next generation cabling system ‘category 8’ to avoid confusion with published ISO/IEC category 7 and category 7A standards, which are indeed supersets of each other and of category 6A. Whilst it’s true that the currently proposed TIA category 8 specifications tentatively describe transmission performance up to 2 GHz for 30 metre channels containing 2 connectors, whereas ISO/IEC specifies category 7A requirements up to 1 GHz for 100 metre channels containing up to 4 connectors, the performance limits proposed for category 8 today do not meet or exceed the category 7A requirements up to 1 GHz.Take note also that category 8 will have a different deployed channel topology and will not be an electrical performance superset of category 7A. In fact, for every transmission parameter except return loss, ISO/IEC category 7A channel and permanent link limits are more severe than those proposed by TIA for category 8 up to 1 GHz. In the case of internal crosstalk parameters, the differences are significant; with category 7A beating category 8 performance by more than 20 dB!For the support of 40GBASE-T transmission, ISO/IEC adopted class I as the name to describe cabling constructed from shielded modular RJ-45 style category 8.1 components and class II to describe cabling constructed from fully-shielded non RJ-45 category 8.2 components. Whilst ISO/IEC is also actively working on a project to characterise the capability of existing category 7A connecting hardware to support 40 Gbit/s data transmission, until the processing capabilities of a 40 Gb/s Ethernet (40GBASE-T) application are finalised, it’s too early to guarantee 40GBASE-T application support distance for any media....................................................................................................................................................................................................................
Established in 1903, Siemon is an industry leader specialising in the design and manufacture of high quality, high performance low voltage infrastructure solutions and services for data centres, LANs and intelligent buildings. Headquartered in Connecticut, USA, with global sales, technical and logistics expertise spanning 100 countries, Siemon offers a comprehensive suite of copper and optical fibre cabling systems, cabinets, racks, cable management, data centre power and cooling systems and intelligent infrastructure management solutions.
With more than 400 patents specific to structured cabling, Siemon Labs invests heavily in R&D and the development of industry standards, underlining the company’s long-standing commitment to its customers and the industry. Siemon Interconnect Solutions (SIS) is a Siemon business unit comprised of a team of dedicated technical sales professionals supported by Siemon Labs, mechanical, electrical and signal integrity engineers committed to solving industry and customer driven interconnect challenges. Siemon provides custom network infrastructure solutions to OEMs, leading manufacturers, value-added resellers and system integrators.
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