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Data Centre Breakthrough

A lot of thought and effort went into the development of SP-3-0092 (Draft 2.0). The intent is to fulfill an important need in the industry.For this month's article I wanted to give a brief overview of...


August 1, 2003  


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A lot of thought and effort went into the development of SP-3-0092 (Draft 2.0). The intent is to fulfill an important need in the industry.

For this month’s article I wanted to give a brief overview of the data centre standard that is now available from Global Engineering Documents as SP-3-0092 (Draft 2.0) for industry ballot review. After ballot resolution, it will be eventually published as TIA/EIA-942, Telecommunications Infrastructure Standard for Data Centres.

The “Telecommunications Infrastructure Standard for Data Centres” is a comprehensive document that in- cludes all aspects of data centre design, including facility planning, the cabling system, and the network design.

Data centres are often designed for much higher levels of availability and security because the high concentration of critical services for a large number of users. This standard includes recommendations on how to implement various levels of availability and security according to a tiered hierarchy. Higher tiers correspond to higher availability and security.

Hierarchical star

Some of the steps involved in the design of a data centre include:

Creating an equipment floor plan including placement of major rooms and spaces;

Providing expected power, cooling, and floor loading requirements;

Providing requirements for telecommunications pathways, and

Designing telecommunications cabling system based on the needs of the equipment to be located in the data centre

The backbone and horizontal cabling are configured in a hierarchical star topology. The data centre is divided into several main spaces that includes the entrance room, the telecommunications room (TR), and the computer room.

The computer room is further subdivided into the main distribution area (MDA), horizontal distribution area (HDA), the zone distribution area (ZDA) and equipment distribution area (EDA).

The data equipment and connectivity components are located in cabinets and racks.

The cabling between racks are usually routed under an access floor in the hot aisle or sometimes in overhead cable trays. Access floor systems, also known as raised floor systems, are used in data centres that need to support high power densities, mid-range systems, or mainframe systems.

Alternatively, overhead cable tray systems may alleviate the need for access floors in data centres. Overhead cable trays can be installed in several layers to provide additional capacity. Typical installations include two or three layers of cable trays, one for power cables and one or two for telecommunications cabling.

The types of cables that are recognized for use in a data centre are 100-ohm twisted-pair cable (ANSI/ TIA/EIA-568-B.2), category 6 recommended (ANSI/TIA/EIA-568-B.2-1), multimode optical fiber cable, either 62.5/125 micron or 50/125 micron (ANSI/TIA/EIA-568-B.3), singlemode optical fiber cable (ANSI/TIA/EIA-568-B.3) and 75-ohm (734 and 735 type) coaxial cable (Telcordia Technologies GR-139-CORE)

For backbone cabling, the maximum supportable distances are application and media dependent. The maximum backbone distances are provided in an informative Annex of the Standard for different applications such as EIA/TIA-232-F and EIA/TIA-561/562, T-1, E-1, T-3 and E-3 circuits.

For horizontal cabling, the maximum distance is 90 m (295 ft) and is independent of media type.

These are the main elements of the data centre standard. The standard also provides extensive information on data centre redundancy, labeling and administration, carrier information and demarcation point, site selection considerations, uninterruptible power supply (UPS) systems, building grounding and lightning protection systems, and fire protection systems. There is also an informative Annex that provides some design examples for corporate and Internet data centres.

There is a lot of thought and effort that went into the development of a data centre standard by a group of industry experts. At this stage the document is a second draft for industry review and comments. It is a significant accomplishment that is intended to fulfill an important need in the industry.

Paul Kish is Director, IBDN Systems & Standards at NORDX/CDT. He is also Vice Chair of the TR-42 engineering committee.

Disclaimer: The information presented is the author’s view and is not official TIA correspondence.