From the May, 2013 Issue of Cabling Installation & Maintenance Magazine
TIA and ISO/IEC cabling-standard development groups are working on specifications for twisted-pair systems to support 40GBase-T. But those specifications are not identical.
by Patrick McLaughlin
At any given time cabling-standard development groups within the TIA (Telecommunications Industry Association; www.tiaonline.org) and the ISO/IEC (International Organization for Standardization; www.iso.org, International Electrotechnical Commission; www.iec.ch) have a number of projects underway. The groups work year-round to establish, refine and revise the cabling specifications that are relied upon worldwide by professionals who specify, design, install or manage structured cabling systems in any number of environments. The cabling-standards-development groups within these organizations also have liaison relationships with the IEEE (Institute of Electrical and Electronics Engineers; www.ieee.org) to coordinate activities when specifications being developed by TIA or ISO/IEC are specifically related to those being developed by the IEEE's 802.3 Working Group.
Such is the case now, in early 2013, as the IEEE charts a course to 40-Gbit/sec data transmission over twisted-pair cabling, while TIA and ISO/IEC committees establish the cabling-system performance levels required to support that data rate. This article will discuss a number of standards-development activities within ISO/IEC and TIA, covering topics such as grounding and bonding, distributed antenna systems, and automated management of cabling infrastructure. But the support of 40GBase-T networking is consuming a significant amount of effort within certain standards groups, and the topic will consume a significant amount of this article as well.
TIA goes for Category 8
As we reported in our December 2012 issue, the TIA's TR-42 Engineering Committee—and in particular the TR-42.7 Telecommunications Copper Cabling Systems Subcommittee—has opted to move forward with the nomenclature Category 8 as its next-generation twisted-pair cabling performance specification. Category 8 twisted-pair cabling will be specified to 2 GHz and is being developed for the express purpose of supporting the IEEE's next-generation Base-T application, 40GBase-T.
In adopting Category 8 as its next performance level, TIA's TR-42 has elected to skip over, presumably forever, a set of specifications defining Category 7 or Category 7A performance for twisted-pair cabling. The ISO/IEC established Category 7/Class F and Category 7A/Class FA performance specifications years ago. (For an opinion column on the Category 7/7A/8 situation and the TIA-ISO/IEC dynamics, see "TIA's great Category 8 debate and ISO/IEC's cabling update," by Valerie Maguire, page 25.)
Much like the TIA has begun to prepare its Category 8 specifications, the ISO/IEC is undertaking standards initiatives to develop twisted-pair cabling specifications to support 40GBase-T. But with its existing Category 7 and 7A specifications in place, the ISO/IEC is looking at the possibility of characterizing Category 7A for 40GBase-T, as well as potentially establishing an entirely new set of specs. To that end, Maguire points out in her article, "While Category 7A is currently specified to 1 GHz, new work items … are extending Category 7A performance characterization out to 2 GHz."
The group that develops cabling specifications within the ISO/IEC is known as JTC1 SC25 WG3 (Joint Technical Committee 1, Sub Committee 25 Interconnection of Information Technology Equipment, Working Group 3 Customer Premises Cabling). A member of WG3 characterized the tenor of that group's recent meeting, held in late February, by saying, "It was apparent from the first day many people weren't pleased that TIA decided to name its next-generation cabling ‘Category 8.'" The sentiment among those individuals was that "TIA should have coordinated with ISO/IEC." Additional objections focused on the fact that some of Category 8's anticipated performance requirements are less stringent than those of Category 7A. (Maguire details these concerns in her column.)
Despite these objections, WG3 got down to business at its meeting and agreed to nomenclature and big-picture parameters for a new generation of 40GBase-T-capable cabling systems. ISO/IEC uses the terms "Category" and "Class" in its cabling standards to characterize the performance levels of the components that make up a cabling channel (Category), and the performance level of the channel itself (Class). So in ISO/IEC terms, a Class E channel comprises components that achieve Category 6 performance; a Class EA channel comprises Category 6A components, and likewise with Class F/Category 7 and Class FA/Category 7A.
At its recent meeting, WG3 agreed on the following parameters.
- Channels that support 40GBase-T will be called Class I and Class II, and will be specified to 30 meters—matching the reach objective specified by IEEE 802.3.
- The components that form Class I channels will be called Category 8.1 and will be backward-compatible with Category 6A components.
- The components that form Class II channels will be called Category 8.2, and will be backward-compatible with Category 7A components.
The TIA and ISO/IEC cabling-standard-development groups clearly are in the early stages of carving their paths toward Category 8/Category 8.1 and 8.2/Class I and Class II cabling systems and performance levels. On April 9 Cabling Installation & Maintenance hosted a web seminar during which three contributors to TR-42.7 provided an update on the standing of Category 8. During the seminar, CommScope (www.commscope.com) engineer senior principal Masood Shariff projected a TR-42/TR-42.7 timetable that included TIA committee ballots finishing in June 2014, ANSI industry ballots finishing in February 2015, ANSI default ballots finishing in October 2015 and the standard—ANSI/TIA-568-C.2-1—publishing right around the end of 2015.
The progress of these TIA and ISO specifications, paralleling the IEEE's development of 40GBase-T, will retain the attention of the cabling industry for many months to come.
Taking AIM at infrastructure
Also at WG3's February meeting, the group reviewed work undertaken by an ad hoc focusing on automated infrastructure management (AIM) systems. WG3 approved a work item to develop a standard for AIM. The ad hoc described the project's purpose and justification as follows: "AIM systems have traditionally focused on their advantages for the administration of information technology cabling infrastructure. In order to promote the use of such systems more widely it is necessary for them to be integrated with other business systems and to encourage development of new applications that AIM applications can serve."
The group also said the proposed (and now accepted) project would "explain how AIM solutions for the administration of information technology cabling infrastructure can contribute to, and bring benefits for, building automation and more general business information systems covering asset tracking, asset management together with event notifications and alerts that assist with physical network security."
Another significant intention of the standard, according to the WG3 ad hoc, is to "propose a common data model for data exchange allowing applications to be developed by third parties which can exploit interfaces to conformant AIM systems, and offer those conformant AIM systems the opportunity to widen their areas of applicability."
Accomplishing that objective will require the participation of individuals with expertise in disciplines, such as software development, that typically are not represented in WG3.
Among the next steps for this group is to develop specifications for several of the standard's clauses. One such clause is aimed at defining "requirements and recommendations for the attributes of AIM solutions for the administration of information technology cabling infrastructure." Another clause aims to define how AIM solutions "can contribute to operational efficiency and deliver benefits to facilities and IT management systems; other networked management systems; business information systems." And still another clause seeks to establish "a framework of requirements and recommendations for data exchange."
The group has ambitions to develop each of these clauses simultaneously, so the initiation of one is not contingent on the completion of another.
Bonding and grounding
Movement is being made in both the ISO/IEC WG3 and TIA TR-42 concerning standards addressing building grounding (earthing) and bonding. The ISO/IEC 30129 standard will be titled Telecommunications Bonding Networks for Buildings and Other Structures. After a productive meeting within WG3, a draft standard was developed. That standard will now go through its regular balloting processes and ultimately be published.
Within TIA, the TR-42.16 Subcommittee on Premises Telecommunications Bonding and Grounding issued a call for interest for document TIA-607-B-2—a second amendment to the 607-B standard. The initial working title of the amendment is Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises Addendum 2 – Structural Metal.
The TR-42.16 subcommittee is developing guidelines based on the following scope: "This addendum specifies additional requirements for a telecommunications bonding and grounding system when using structural metal in place of the telecommunications bonding backbone (TBB) or grounding equalizer (GE). This addendum is not intended for verification of structural metal."
DAS and other wireless
An effort underway within TIA TR-42 to develop a standard for communications systems in educational facilities has brought distributed antenna system (DAS) technology into the standards fold. A task group within TR-42.1 Subcommittee on Commercial Building Telecommunications Cabling has made progress on a project to develop what will be published as TIA-4966, covering telecommunications systems for educational facilities. That standard, which is in the balloting process, will include an informative annex covering DAS.
In its current form the annex to TIA-4966 is approximately three pages in length. It discusses DAS, includes a generalized diagram of a DAS, and discusses the components and media types frequently used in a DAS. As an informative annex, it is not part of the standard "proper" and once published it will not have the same rule-of-enforcement, so to speak, that the specifications contained within TIA-4966 will have.
The impetus for developing TIA-4966 was the work of the Educational Facilities Task Group, which completed the work that laid the foundation for the standard now in development. At its February meeting, TR-42.1 agreed to rename the Educational Facilities Task Group the DAS Task Group. Essentially the same group of contributors that initiated the TIA-4966-development process is now focusing specifically on DAS. As of its February meeting, the group remained in the information-gathering stage and had not created a draft document.
Separately, a different task group is working to revise the document TSB-162 Telecommunications Cabling Guidelines for Wireless Access Points. The TSB-162 Revision Task Group recommended, and TR-42.1 agreed, to keep itself separate from the DAS Task Group. The TSB-162 Revision Task Group has created a draft revision to the telecommunications systems bulletin.
Standards are sometimes referred to as the bedrock of structured cabling systems, as they are the basis upon which many systems are specified, designed, installed and maintained. The process of keeping cabling standards up to date, relevant to current needs, and forward-looking to the benefit of system users is ongoing. As such, any one cabling standard is never too far away from the development process, either having recently been developed or revised, under consideration for affirmation or withdrawal, or being reviewed for a next revision. The standards and other documents mentioned in this article are in the midst of that creation/revision cycle. Others will soon follow. We intend to keep you updated on the efforts of the cabling industry's standards-making bodies. ::
Patrick McLaughlin is chief editor of Cabling Installation & Maintenance.
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