Cabling Standards 2 TIA De-Mystifying. Editorial Guide

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1 Editorial Guide New Structured Cabling Standards sponsored by: Certain standards produced by the Telecommunications Industry Association, International Organization for Standardization and Institute of Electrical and Electronics Engineers significantly affect the design, installation and performance of structured cabling systems, and frequently inter-relate with each other. This Cabling Installation & Maintenance editorial guide includes information on some of their most recently introduced standards and some that are still in development. 2 TIA-1179 addresses cabling in healthcare 9 The revised TIA-942 Data Center standard 18 Extend your cabling s capabilities 24 De-Mystifying Cabling Specifications

2 TIA-1179 addresses cabling in healthcare facilities Specifications in the new standard are game-changers for pathways and work areas in healthcare environments. By Brian Ensign, RCDD, NTS, OSP, CSI and Carol Everett Oliver, RCDD, ESS Ratified in August 2010, the ANSI/TIA-1179 Healthcare Infrastructure Standard is the culmination of work that took place within the TIA TR-42 Engineering Committee. It is an example of the newer generation of standards from the TIA that address cabling infrastructure within specific areas or environments. A healthcare facility has different types of workspaces, including labs, patient rooms and other spaces in addition to areas that resemble more-traditional workspace environments. While the TIA-568 series of standards effectively addresses cabling in traditional premises environments, the connectivity needs of healthcare facilities are far more complex than commercial buildings, and can be optimized only through a standard that recognizes their particular and often unique requirements. TIA does just that. In fact the standard was initiated by a group of healthcarefacility end-users who approached the TIA and stated that although they liked the then-current TIA-568-B standard, healthcare facilities had design, installation and construction considerations that 568-B did not address. Approximately half the members of the group that drafted and ultimately approved the TIA-1179 standard were healthcare-facility users. 2 The standard can be described as a game-changer in how designers, installers and users of structured cabling systems look at the spaces in those systems.

3 TIA-1179 addresses cabling in healthcare facilities Market drivers A combination of market, technical and regulatory drivers has brought healthcare facilities to the forefront, from a business standpoint, for the cabling industry. For more than a decade some provisions in the Health Insurance Portability and Accountability Act (enacted in 1996) have driven the electronic capture and storage of patient medical records. More recently the Health Information Technology for Economic and Clinical Health (HITECH) Act reinforced and even expanded security provisions of HIPAA, and further prompted healthcare facilities of all kinds to store medical records electronically. With a significant amount of patient data now available electronically, medical professionals have been finding ways to use this data to conduct trend analysis and data mining while maintaining the mandated privacy and confidentiality of HIPAA and HITECH. Medical researchers are now able to aggregate patient data to assist in their diagnosis and prevention efforts. The idea of patient data as a tool for medical research comes with the need for storage networks in which this data is housed. Another growing trend in the medical-research field that is also driving the need for more robust networks is long-distance collaboration. A prime example is a surgical procedure being transmitted via video. Today when a patient is undergoing surgery, the on-site surgeon may be accompanied by a consulting surgeon who is at a remote location but can view the surgical procedure via video. Pathways in focus The TIA-1179 standard specifies requirements for telecommunications infrastructure intended to support a wide range of healthcare facilities and systems to include cabling, topology, pathways and work areas, and the devices attached to it. As mentioned earlier, pathways and work-area spaces within healthcare facilities are significantly different from those found in commercial buildings, and the 1179 standard addresses this reality. 3 The standard recommends a minimum of two diverse pathways from the entrance facility to the equipment room. Doing so allows the user to segregate more-traditional network-type applications such as voice and data from other critical applications that are more specific to healthcare, such as imaging and diagnostic communications. Additionally, this type of pathway redundancy is

4 TIA-1179 addresses cabling in healthcare facilities crucial because in these healthcare environments, the network supports not only data or information flow, but often it quite literally supports the life and health of hospital patients. The TIA-1179 standard also recommends larger equipment rooms and telecommunications rooms (TRs) than we re used to seeing. The standard recommendation allows for 100 percent growth when planning these spaces. That may initially sound excessive, but a significant consideration behind this recommendation is to prevent future disruption of rooms, hallways and other areas within a hospital. Hand-in-hand with this consideration is the standard guideline that the cabling-system pathways should not compromise the facility s operation. Infection control requirements (ICRs) are a key factor in how much, or how little, access cabling-system technicians and managers will have to pathways in healthcare facilities. Consequently the 1179 standard advises that users may want to implement enclosed pathways, especially in air-handling spaces, to meet these ICRs. In general cabling-system designers are accustomed to using these open plenum spaces in which to route cables. In many cases they will find themselves without that luxury in healthcare facilities, challenging these design professionals to develop alternative system designs. Another recommendation in the standard is to segregate cables for different networks and applications due to safety protocols. In practice this means keeping cables separate in accordance with the networks the cables are serving, the specific part of the network they re serving, or the work-area classification. Redefining the work area 4 Perhaps the most significant difference between a healthcare facility and a commercial office building and, not coincidentally, a major difference between TIA-1179 and the TIA-568 series of standards is the treatment of work area spaces. Very much in contrast to the work area of a commercial office building, in which a communications outlet might service a computer, phone, printer and perhaps another user-administered device, a work area in a healthcare facility can take many forms. TIA-1179 addresses this reality by defining 11 work-area classifications. Each of those 11 classifications is further broken down into subgroups, and in total there are 75 work-area types defined in the standard.

5 TIA-1179 addresses cabling in healthcare facilities The 11 work-area classifications defined in TIA-1179 are: Patient Services, Surgery/ Procedure/Operating Rooms, Emergency, Ambulatory Care, Women s Health, Diagnostic and Treatment, Caregiver, Service/Support, Facilities, Operations, and Critical Care. Each of these 11 work-area classifications and the subgroup work areas within them is characterized in the standard as a low-, medium- or high-density work area. The standard calls for 2 to 6 outlets, or ports, in a low-density work area; 6 to 12 outlets in medium-density work areas; and more than 14 outlets in highdensity work areas. For several high-density work areas, the need for redundancy is a driving force behind the number of outlets recommended. At the same time, many of these workarea spaces must be equipped to handle multiple temporary connections, such as test apparatus. Picture, for example, a patient room in which tests are conducted on the patient a handful of times per day. The diagnostic equipment used to conduct these tests travels from patient to patient and is plugged in only for the duration of the test being conducted. It is then unplugged and moved to another patient room. Yet the communications outlet must be available and ready at all times. The redundancy inherent in some of these high-density work areas helps to ensure that network connectivity contributes to, rather than detracting from, patient care. Conversations with healtchcare-facility end users have confirmed that many of them have been planning high outlet counts in their most-critical work areas for these and other reasons. The many users who have faced this situation for some time now have in TIA-1179 a standard to which they can refer as an industry-agreed-upon figure for the number of outlets in these areas. Of the 75 total work-area types recognized in the standard, 45 percent are designated as low-density, 25 percent are designated as medium-density and 30 percent are designated as high-density. Putting the standard into practice 5 Many real-life examples exist of the principles in TIA-1179 being put into practice in a hospital or other healthcare facility. One example is Johns Hopkins Hospital in Baltimore, MD.

6 TIA-1179 addresses cabling in healthcare facilities Many new hospitals can have more than two dozen different low-voltage systems and while not all of those systems are necessarily Internet Protocol (IP)-based at the current time, convergence is rapidly taking place. Many facilities are being cabled today to support the eventual transition of these low-voltage systems to IP. The new TIA healthcare infrastructure standard recommends a minimum of Category 6 copper cabling for horizontal runs, as well as 50-micron multimode fiber-optic cabling for high-bandwidth transmissions such as computed tomography (CT) scans and magnetic resonance imaging (MRI) exams. For backbones, the standard recommends multimode and singlemode fiber-optic cabling. As mentioned earlier, these backbones should be redundant. Several factors make retrofitting a healthcare facility a difficult prospect, including the aforementioned ICRs and the TIA-1179 recommendation to use enclosed pathways to name just a couple. With these and other contributing factors in mind, as well as the bandwidth requirements and mission-critical nature of communications within healthcare facilities, it is recommended to design cabling systems to support the longest possible lifecycle. While retrofitting is a difficult task, it is the reality for the many facilities that do not have the luxury of building a new system with the proverbial blank canvas. The TIA-1179 standard recommends the use of multi-user telecommunications outlet assemblies (MUTOAs) to provide the flexibility of adding up to 24 additional outlets to a work area. One important fact to keep in mind is that although MUTOAs provide flexibility, they also represent an additional potential point of failure in a system. So installers must take care when retrofitting a workspace with MUTOAs as the standard does not recommend this practice for new facilities. Also, notably, the TIA-1179 standard does not recommend the use of consolidation points (CPs) to add outlets to a work area. 6 Power over Ethernet (PoE) is also a consideration to make when cabling healthcare work areas. As mentioned earlier, some of the low-voltage applications used in healthcare facilities today are not IP-based but may transition to IP in the future. The ability to power these devices using the copper conductors of an unshielded twisted-pair cable, or the copper conductors within a composite copper/fiber cable construction, allows a facility to accommodate any PoE-enabled applications deployed

7 TIA-1179 addresses cabling in healthcare facilities today and provides the infrastructure needed for future PoE-enabled applications. Because of the critical nature of this environment, backup power via redundant uninterruptible power supply systems is recommended for all PoE injection systems. Some other best-practice recommendations that are likely to apply in healthcare facilities include considering multifiber cable, preferably preterminated, in highdensity work areas. These cable constructions will be cost-effective, reliable and the least disruptive in sensitive environments. Also, cables installed in hospitals will be subject to high levels of electromagnetic interference (EMI), temperature swings from area to area, and the possibility of contact with chemicals and other gases. These considerations may affect your choice of cables and may affect the manner in which those cables are installed. Exposure to chemicals and other gases once again brings up the issue of pathways. The pathways in which these exposures may happen are crowded with specialized air and gas-delivery systems as well as more-traditional HVAC and other systems. Cables installed in these pathways must be able to withstand these environments without degradation. One of TIA-1179 s recommendations, mentioned earlier, is to segregate cables based on the applications or services they are supporting. One practical way to accomplish this is to color-code cables and connectors so they can be identified easily. While the TIA-1179 standard recommends color-coding cable, the standard does not specifically designate certain colors for services or applications. Finally, as with all cabling installations, those that take place in hospitals must meet approval by the local authority having jurisdiction (AHJ). It is certainly in the best interest of everyone involved to research state, regional and local safety codes. Brian Ensign is director of training and technology with Legrand Ortronics and Carol Everett Oliver is market analyst with Berk-Tek. 7

8 We re Not Going Green. We Already Are. At Siemon, we ve worked hard to be the most green and sustainable network infrastructure company in the world, so that our customers can deploy environmentally responsible cabling systems without sacrificing performance. Just a few of Siemon s Green Achievements: 300% Carbon-Negative Operations Zero-Landfill Recycling/Waste Management 217 KW Solar Power Plant Forestland Conservation ISO Environmental Management RoHS Compliance We also help our customers build more sustainable infrastructures though green technology, design strategies and recommendations for: Future-Proof Infrastructures Resource Management/Maximization Reducing Power Consumption Thermal Efficiency Cabling Abatement/Recycling Planning To find out more about Siemon s Environmental Sustainablity Achievements, visit: W W W. S I E M O N. C O M

9 What will be in the revised version of the TIA-942 Data Center standard? Five years after initial publication, revisions are underway for the TIA s data center cabling specification. By Jonathan Jew ANSI/TIA-942, one of the Telecommunications Industry Association s (TIA) best-selling standards, is undergoing revision. All American National Standards Institute (ANSI) standards must be reaffirmed, withdrawn, or revised every five years. Since ANSI/TIA-942 was published in 2005, it was readily apparent that it needed to be revised. The revision to TIA-942 will be named TIA-942-A. New TIA cabling standards scheme Because TIA-942 was published after the restructuring of the TIA-568 series cabling standards, TIA-942 needed to be modified to fit into the new TIA premises telecommunications cabling standards scheme. In this new scheme, common information that applies to multiple types of premises is in common standards, and information specific to a particular type of premises is in premises standards such as TIA-942. Component standards deal with the specification of components and are intended primarily for component manufacturers. This scheme is meant to improve ease of use, efficiency, and ensure consistency between standards. Some of the changes that will be made in TIA-942-A to incorporate it into the new scheme include the following: :: Reference the generic telecommunications cabling topology, terms, and 9 environmental classifications described in TIA-568-C.0.

10 What will be in the revised version of the TIA-942 Data Center standard? ANSI/TIA-942-A will be a Premises Standard (middle column) in TIA s new standard scheme. That means information that applies to multiple types of premises including data centers will be found in Common Standards (left column), while information specific to data centers will be found in 942-A. :: Move content regarding bonding and grounding into the draft TIA-607-B standard, which provides much more information regarding telecommunications grounding and bonding. Because bonding and grounding are important for all premises, it is appropriate for this content to be in a generic rather than a premises standard. 10 :: Remove content regarding labeling in computer rooms and instead refer to TIA-606-A Addendum 1, which was published in late 2008 and deals specifically with computer room and equipment room administration. Eventually, TIA- 606-A will be superseded by TIA-606-B, which will incorporate the addendum

11 What will be in the revised version of the TIA-942 Data Center standard? In an early draft, TIA-942-A includes the addition of the intermediate distribution area (IDA) and intermediate crossconnect (IC) to serve the needs of larger data centers. 11 and extend the concepts in TIA-606-A to administration outside computer rooms and equipment rooms.

12 What will be in the revised version of the TIA-942 Data Center standard? :: Move content regarding racks and cabinets to the draft TIA-569-C standard (because cabinets and racks are used in all types of premises). :: Replace power and telecommunications cabling separation distances with a reference to the more-detailed information being developed for TIA-569-C. :: Move content regarding outside plant pathways to the draft TIA-758-B outside plant standard. Incorporating TIA-942 addenda TIA-942-A will incorporate the contents of two addenda to TIA-942. TIA Data center coaxial cabling specifications and application distances. Addendum 1, published in 2008, provides additional specifications for coaxial cable connectors used for T-3, E-1, and E-3 circuits. It permits longer horizontal cabling from the main distribution area (MDA) for coaxial cable used for these circuits, and provides revised circuit distance guidelines for T-1, T-3, E-1, and E-3 circuits in data centers using the new component specifications. TIA Additional guidelines for data centers. Addendum 2, which was approved in late 2009 and should be available now, provides additional guidelines on a wide variety of subjects, the most important of which are revisions to improve energy efficiency. The addendum accomplished the following: :: Specified a wider range of temperatures and humidity in data centers based on revised guidelines published in 2008 by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE). :: Specified a three-level lighting protocol to reduce energy usage. :: Added Category 6A to supported media and specified it as the recommended media for balanced twisted-pair cable. :: Added guidance to check with equipment manufacturers regarding radio sources (wireless LANs, cellular telephones, handheld radios, etc.) in computer rooms and entrance rooms. :: Updated data center Tiering reference guide. 12

13 What will be in the revised version of the TIA-942 Data Center standard? While harmonization between TIA and international standards is an ideal, one should not expect all the terminology used in the ISO/IEC and CENELEC EN standards to be included in TIA-942-A. International standard influence 13 The recently approved ISO/IEC international data center telecommunications cabling standard will likely influence some of the changes that will be made in TIA-942-A because it is desirable to harmonize with international standards. The ISO/IEC standard may have an impact on several aspects of TIA-

14 What will be in the revised version of the TIA-942 Data Center standard? 942-A, including terminology, maximum horizontal cabling lengths, cabling types, and connectors. Terminology. The ISO/IEC standard, published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), only deals with telecommunications cabling and is primarily based on the European data center cabling standard CENELEC EN , which was published in Both the ISO/IEC and CENELEC standards use terminology that is different from that found in TIA-942. For example, what TIA-942 calls the horizontal crossconnect (HC) located in the horizontal distribution area (HDA), the ISO/IEC and CENELEC standards call the zone distributor (ZD). Because ISO/ IEC does not deal with spaces, there is no equivalent in that standard for spaces such as the MDA or HDA. It is unlikely that TIA-942 terms will be changed to match the ISO/IEC terminology. However, it is expected that terms for parts of the infrastructure not named in TIA-942 will be adopted in TIA-942-A. Examples are the equipment outlet (EO) and external network interface (ENI). Maximum horizontal cabling lengths. The ISO/IEC and CENELEC data center standards permit various maximum cabling lengths for zone distribution cabling (horizontal cabling) based on the type of cabling employed. Balanced-pair zone distribution cabling is limited to a maximum of 100 meters, but optical-fiber cabling lengths are only dependent on the channel-length restrictions for the cabled optical fiber category used (i.e., 300 meters for OF-300 channels, 500 meters for OF-500 channels, and 2,000 meters for OF-2,000 channels). TIA-942 has only two exceptions to the normal rule that horizontal cabling is limited to 100 meters, as follows. 1. 1Up to 300-meter horizontal optical-fiber cabling originating from the MDA in data centers where no HDA is present. 2. Up to 300 meters horizontal 75-ohm coaxial cabling originating from the MDA. 14 TIA-942-A will probably remove horizontal cabling distance restrictions for optical fiber other than the application-dependent restrictions specified in TIA-568-C.0.

15 What will be in the revised version of the TIA-942 Data Center standard? Removing such restrictions will permit more flexibility in designing optical-fiber networks such as storage area networks. Cabling. ISO/IEC specifies a minimum of Class EA (Category 6A) for all balanced-pair except network access cabling cabling originating from the entrance room. TIA-942 permits the use of Category 3 through 6A for both backbone and horizontal cabling, but recommends Category 6A. TIA-942-A will probably eliminate the use of one or more of the lower Categories of cables for balanced twisted-pair horizontal cabling. ISO/IEC specifies a minimum of OM3 (50/125-micron 850-nanometer laseroptimized multimode fiber) for all multimode optical fiber in data centers. Connectors. Unlike TIA-942, which specifies no particular connectors, ISO/IEC specifies the following connectors. LC and MPO for multimode fiber at the EO and ENI; LC and MPO for singlemode fiber EO; Angled LC connector for singlemode fiber at the ENI. TIA will probably recommend but not require the use of LC and MPO connectors. Other new content TIA-942-A will include a new section on energy-efficient design, including recommendations regarding the design of telecommunications cabling, pathways, and spaces to improve energy efficiency. This content will be in addition to the energy-saving measures provided in TIA-942 Addendum 2. To handle large data center topologies, TIA-942-A will add a new space named the intermediate distribution area (IDA), containing a new second-level backbone distributor named the intermediate crossconnect (IC). Practical experience has shown that very large data centers may require this second-level distributor. For example, a large data center could include several computer rooms, each of which could have one or more IDAs to act as central points of administration for the room. For an example data center using this setup, see the figure titled Draft TIA- 942-A Example Data Center Topology on page The potential changes described in this article are being considered by TIA TR-42.1, the subcommittee responsible for TIA-942-A. Please note, though,

16 What will be in the revised version of the TIA-942 Data Center standard? that many of them may not make it into the final publication. Also, there will be other modifications to TIA-942 that were not described here. Because we are at the beginning stages of the revision, it is difficult to tell what those modifications will be. If all goes well, TIA-942-A could be published sometime in Jonathan Jew is president of J&M Consultants ( 16

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18 Extend your cabling s capabilities with four-pair PoE n wireless LANs and IP surveillance systems are requiring more power than ever before. By Sani Ronen Ethernet cable has become the universal backbone for communications networks. Now with the advent of Power over Ethernet (PoE) technology, it also has become the electricity backbone, fueling a growing variety of digital devices from Wi-Fi wireless access points and notebook computers to video surveillance cameras. 18 The ratification of the IEEE 802.3at standard in September 2009 enabled PoE to deliver 30 watts of safe power over a single Ethernet cable to an even broader range of gear including access control systems, pan/tilt/zoom (PTZ) cameras, outdoor cameras and even full outdoor solutions that include a heater. The growing use of n Wi- Fi technology has been one of high-power PoE s drivers. The The latest IEEE 802.3at standard enables PoE to power a much broader range of powered devices, from n wireless access points, subscriber stations and 3G/LTE femtocells, to perimeter security equipment, videoconferencing and telephony products and thin clients.

19 Extend your cabling s capabilities with four-pair PoE multiple-input/multiple-output (MIMO) architecture used by n technology inherently requires more power than previous technologies, like a and b/g. And n brings about bigger operating ranges that transform it into a better candidate for mesh networks for physical security, in which the wireless local area network (LAN) access points are always connected in tandem with a network camera, and is expected to power it. These two trends make IEEE 802.3at PoE Plus capabilities crucial for the efficient deployment of n in its full splendor. A key way that PoE system developers are addressing these challenges is by employing the option to implement PoE functionality over all four pairs of the Ethernet cable. This option opens the door for safely delivering 60 watts of direct current (DC) power over a single Ethernet cable, using current levels of 600 milliamp (ma) rather than the 1.2 Amp level of two-pair 60W midspans. With the latest four-pair 802.3at solutions, cabling professionals can go well beyond the 25.5W of two-pair solutions to support powered device (PD) power consumption of 51W, using fully compliant industry-standard 60W PoE technology at the source. And because it is backed by IEEE standards, today s 802.3at-compliant technology incorporates all necessary PD PoE compliance detection features for safe powering as well as safe PD disconnection in overload, short-circuit or under-load conditions. How four-pair powering works The original, standard-power 802.3af specified that a PoE switch or midspan will deliver up to 15.4W. It also defined consumption of up to 12.95W by the powered device, which may be installed up to 100 meters from the switch. This power limitation prevented high power devices that required up to 30W, such as PTZ cameras and advanced access control solutions, to be supported via the industrystandard PoE solution. 19

20 Extend your cabling s capabilities with four-pair PoE The new high-power 802.3at standard roughly doubled what power sourcing equipment (PSE) can deliver and what PDs can receive to 30W and 25.5W, respectively. It also increased PSE output voltage to between 50 and 57V, and boosted maximum ongoing current to 600mA. One of the most important benefits of the IEEE 802.3at standard was that it relied on the field-proven detection and protection concepts of the existing 802.3af standard, thus enabling fast and safe adoption of the new standard. Even more importantly, the IEEE 802.3at-2009 standard changed the definition of a PD, compared to the previous IEEE Clause 33. The new standard considers the PD to be the powered interface, as opposed to the entire device being powered. This means that one can have two power interfaces, each taking 25.5W, inside the same box. Nothing precludes these to be connected one over the two pairs using lines 1, 2, 3 and 6 and the other over the two pairs using lines 4, 5, 7 and 8. This is what makes it possible to double the standard 802.3at-2009 maximum of 25W and go up to 51W while fully complying with the standard. The primary applications for 51W PoE power delivery are full systems that include an IP camera with additional power-consuming accessories such as a heater. In the access control market, a full system that includes a controller, a reader and a few door locks can easily consume 45W of power or more. Powering over all four pairs of Ethernet cable not only boosts power delivery to PDs but also improves efficiency compared to two-pair solutions. Rather than delivering 51W over twisted-pair cable via a four-pair solution, this same four-pair configuration can be used to power two-pair devices with 30W of power, while dissipating up to half the power and consuming almost 15% less energy than conventional two-pair solutions. This translates into savings of approximately $25 per year per powered device, assuming energy costs of $0.10 per kilowatt hour. 20 Finally, the four-pair configuration offers the opportunity to extend cabling lengths. Type 1 devices assume the same legacy cabling infrastructure (Category 3) that was the minimum required for 802.3af. So if Type 1 devices are used with worst-case Category 5 cables, the cables could actually be 60% longer. The resistance of the Category 5 cables is equivalent to Category 3 cables, or 480 feet. Of course, this scheme would only work if the physical layer (PHY) device being used to transmit data could also support these long distances.

21 Extend your cabling s capabilities with four-pair PoE Switch vs. midspan Cabling professionals can deploy the latest high-power PoE technology in the cabling infrastructure either by upgrading the switch or by adding midspans to the existing switch infrastructure. Typically the most flexible, scalable, manageable and energy-efficient way to deploy PoE is by using midspans, especially in first-time PoE deployments. They require no changes to the existing switch or cabling, and are generally compatible with any Ethernet switch. One major advantage of midspans reliability is especially apparent with the higher power standards. The mean time between failure (MTBF) of PoE switches is considerably lower, when compared with their non-poe counterparts. This is due to the concentration of high-power dissipation from the PoE section and the highly sensitive data section into a single box. For example, Cisco s 3750X-48T (non-poe) product has 171,846 hours of MTBF, while the 3750X-48P (its PoE counterpart) product has an MBTF of 139,913 hours an almost 20% smaller lifetime. Even worse, once there is an issue, one pays for both data and power again, instead of dealing only with the section where the issue exists. Another advantage of midspans is that they are more flexible and scalable than switches. They enable PoE ports to be added, incrementally, only as needed rather than having to invest in advance for future growth at the time of installation. The inclusion of an interlocking feature enables the power infrastructure to be expanded in one-port midspan increments as the new PDs are added. Flexibility is further enhanced with midspans through the inclusion of a gigabit interface so they can more easily support high-power PTZ cameras and thin clients. Other options that enhance flexibility include the ability to use DC inputs with external power supplies for incremental power capacity or redundancy, and flexible powering from alternating current (AC), DC or another midspan. Interconnected midspans can also back each other up. 21 Once deployed, a midspan-based PoE infrastructure is also easier to manage and maintain than one driven by a PoE-capable switch. Midspans deliver remote power-management capabilities that support both IPv4 and IPv6/addressing, which allows simple and efficient monitoring and control of powered devices. This increases in importance with network size and complexity. Remote power management also enables unit scheduling uninterruptible power supply (UPS)

22 Extend your cabling s capabilities with four-pair PoE Safe PoE powering is ensured by first performing PD detection, followed by PD classification to determine a PD s consume power level prior to its ignition. Gradual startup avoids high-frequency data interference; real-time protection and power management during operation ensure system safety. Any PD disconnection is followed by a fast power shutdown. power monitoring and Web-based monitoring. Malfunctioning remote devices can be reset, eliminating an expensive service call. Midspans also enable centralized control of multi-site or multi-building installations, with support for immediate alert (e.g. E911) and response if IP phone status changes. When the midspan is integrated with a UPS system, the remote power-off/power-on capability also enables low-priority ports to be disconnected during power failures. Remote power management must be performed in a secure fashion, so SNMPv3 management is recommended to prevent malefic agents from interfering with network operations. 22 Finally, midspan-based PoE solutions also significantly improve energy efficiency. The remote-management features alone provide an easy way to power selected ports up or down during the day, which can reduce power consumption by 70%. Each device s power consumption can be measured and its average power consumption can be actively reduced. A typical 1U 24-port midspan that has 24 x 15.4W, or 370W of total power to manage, may only have real-time power needs of

23 Extend your cabling s capabilities with four-pair PoE just over half that amount for the various PDs on the network. Additionally, today s enterprise-grade PoE midspans use a distributed power architecture, augmenting smaller, more-economical internal default power supplies with external power supplies either for incremental additional power or for redundancy. This further improves midspans already excellent system efficiency, and reduces cooling costs because smaller supplies require smaller and/or lower-speed fans. As mentioned earlier, this approach also enables midspans to back each other up, with additional power supply serving the highest-priority system ports. Protecting outdoor gear Another key consideration for cabling professionals is whether their powering solution can support the environmental requirements of outdoor PDs such as IP cameras. Until recently PoE could only be deployed safely if it were paired with a surge-protection unit to prevent direct or nearby lightning strikes from damaging or destroying both the PDs and their network switch. Without lightning protection, surges also can move quickly along the Ethernet cable to damage expensive indoor network switches. Because surge- and lightning-protection units can cost anywhere from $250 to $400, many cabling professionals consider them to be a discretionary item. Unfortunately, nearby lightning strikes are much more common than most people think, and even at a mile away can induce a voltage level capable of damaging outdoor devices. A midspan with integrated surge protection reduces lightning-protection costs by as much as 80% compared to using standalone surge-protection equipment. Today s latest midspans provide higher power delivery and improved energy efficiency, while offering a significantly more flexible and scalable alternative to PoE-enabled switches. Cabling professionals can optimize their PoE deployment by choosing midspans that are capable of industry-standard powering on spare pairs in compliance with IEEE 802.3at standards, and that also feature such capabilities as lightning protection that are critical for network gear deployed outdoors. 23 Sani Ronen is Product Marketing Manager in Microsemi Corporation s analog mixed signal group.

24 F R O M 5 e T O 7 A De-Mystifying Cabling Specifications From 5e to 7 A Structured cabling standards specify generic installation and design topologies that are characterized by a category or class of transmission performance. These cabling standards are subsequently referenced in applications standards, developed by committees such as IEEE and ATM, as a minimum level of performance necessary to ensure application operation. There are many advantages to be realized by specifying standards-compliant structured cabling. These include the assurance of applications operation, the flexibility of cable and connectivity choices that are backward compatible and interoperable, and a structured cabling design and topology that is universally recognized by cabling professionals responsible for managing cabling additions, upgrades, and changes. CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

25 F R O M 5 e T O 7 A The Telecommunications Industry Association (TIA) and International Standard for Organization (ISO) committees are the leaders in the development of structured cabling standards. Committee members work hand-in-hand with applications development committees to ensure that new grades of cabling will support the latest innovations in signal transmission technology. TIA Standards are often specified by North American end-users, while ISO Standards are more commonly referred to in the global marketplace. In addition to TIA and ISO, there are often regional cabling standards groups such as JSA/JSI (Japanese Standards Association), CSA (Canadian Standards Association), and CENELEC (European Committee for Electrotechnical Standardization) developing local specifications. These regional cabling standards groups contribute actively to their country s ISO technical advisory committees and the contents of their Standards are usually very much in harmony with TIA and ISO requirements. While the technical requirements of TIA and ISO are very similar for various grades of cabling, the terminology for the level of performance within each committee s Standards can cause confusion. In TIA Standards, cabling components (e.g. cables, connecting hardware, and patch cords) are characterized by a performance category and are mated to form a permanent link or channel that is also described by a performance category. In ISO, components are characterized by a performance category and permanent links and channels are described by a performance class. TIA and ISO equivalent grades of performance are characterized by their frequency bandwidth and are shown in table 1. TABLE 1: TIA AND ISO EQUIVALENT CLASSIFICATIONS FREQUENCY BANDWIDTH TIA COMPONENTS) TIA (CABLING) ISO (COMPONENTS) ISO (CABLING) MHz Category 5e Category 5e Category 5e Class D MHz Category 6 Category 6 Category 6 Class E MHz Category 6A Category 6A Category 6 A Class E A MHz n/s n/s Category 7 Class F 1 1,000 MHz n/s n/s Category 7 A Class F A CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

26 F R O M 5 e T O 7 A When faced with the daunting task of upgrading an existing network or designing a new building facility, cabling experts are encouraged to look to the Standards for guidance on performance and lifecycle considerations. Both TIA and ISO state that the cabling systems specified in their Standards are intended to have a useful life in excess of 10 years. Since applications, such as Ethernet, typically have a useful life of 5 years, it is recommended practice to specify cabling systems that will support two generations of network applications. For most commercial building end-users, this means specifying a cabling plant that is capable of supporting 1000BASE-T (Gigabit Ethernet) today and a planned upgrade to 10GBASE-T in 5 years. TIA categories and ISO classes of structured cabling that are recognized for the support of data-speed applications are specified in the Standards listed in Table 2. TABLE 2: TIA AND ISO STANDARDS REFERENCES TIA CABLING STANDARDS Category 5e ANSI/TIA-568-C.2, Balanced Twisted-Pair Telecommunications Cabling and Components Standard, 2009 Category 6 ANSI/TIA-568-C.2, Balanced Twisted-Pair Telecommunications Cabling and Components Standard, 2009 Category 6A ANSI/TIA-568-C.2, Balanced Twisted-Pair Telecommunications Cabling and Components Standard, 2009 ISO CABLING STANDARDS Class D ISO/IEC 11801, 2nd Ed., Information technology Generic Cabling for Customer Premises, 2002 Class E ISO/IEC 11801, 2nd Ed., Information technology Generic Cabling for Customer Premises, 2002 Class E A Amendment 1 to ISO/IEC 11801, 2nd Ed., Information technology Generic Cabling for Customer Premises, Class F ISO/IEC 11801, 2nd Ed., Information technology Generic Cabling for Customer Premises, 2002 Class F A Amendment 1 to ISO/IEC 11801, 2nd Ed., Information technology Generic Cabling for Customer Premises, CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

27 F R O M 5 e T O 7 A CATEGORY 5E/CLASS D Category 5e/class D cabling requirements were first published in 2000 in order to address the additional transmission performance characterization required by applications such as 1000BASE-T that utilize bi-directional and full four-pair transmission schemes. The Standard added headroom to category 5 performance limits and characterized several new transmission criteria that were required for support of Gigabit Ethernet over a worst case four-connector channel (the 1000BASE-T application was originally targeted for operation over category 5 channels having just two-connectors). To ensure that additional performance margins were satisfied, category 5e/class D specifications added headroom to the parameters of NEXT loss, ELFEXT loss, and return loss and introduced the characterization of crosstalk using power summation, which approximates the total crosstalk present when all pairs are energized as in a four-pair transmission scheme. Although no longer recognized by the Standards for new installations, a substantial number of installed category 5 channels are likely to support the 1000BASE-T application. Information on the qualification of legacy category 5 installations for this application can be found in annex M of ANSI/TIA-568-C.2. CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

28 F R O M 5 e T O 7 A CATEGORY 6/CLASS E The majority of structured cabling specified for new buildings in the past 5 years has been category 6/class E rated because it provided the maximum performance headroom and return-on-investment. Category 6/class E cabling delivered double the signal-to noise margin (attenuation-to-crosstalk margin is positive to 200 MHz) of category 5e/class D cabling and provided the performance headroom desired by end-users to ensure that their cabling plant could withstand the rigors of the cabling environment and still support 1000BASE-T when it was time for an application upgrade. The category 6/class E cabling specification development process also brought to light the need to limit the conversion of differential mode signals to common mode signals and vice versa through the characterization of component balance, resulting in cabling systems with improved electromagnetic compatibility (EMC) performance. Although, category 6/class E cabling was primarily targeted to support 100BASE-T and 1000BASE-T applications, the good news is that some of the installed base of category 6/class E cabling can support the 10GBASE-T application. The TIA TSB-155-A and ISO/IEC technical bulletins identify the additional performance headroom, as well as applicable field qualification test requirements and procedures, which must be satisfied by the installed base of category 6/class E cabling in order to support the 10GBASE-T application. Since the digital signal processing (DSP) capabilities of the 10GBASE-T application result in full internal pair-to-pair crosstalk cancellation, this application is particularly sensitive to undesired signal coupling between adjacent components and cabling. This coupling is called alien crosstalk and the characterization of alien crosstalk in the installed category 6/class E cabling plant is the main focus of the TIA TSB-155-A and ISO/IEC technical bulletins. Because the alien crosstalk in category 6/class E UTP cabling is extremely dependent upon installation practices (e.g. bundling, the use of tie-wraps, and pathway fill), performance values were developed based upon a typical worst case environment meaning that 10GBASE- T should operate over category 6/class E UTP channel lengths of up to 37 meters and may operate over channel lengths of 37 to 55 meters of category 6/class E UTP cabling depending upon the actual alien crosstalk levels present. Since the overall foil in category 6/class E F/UTP cabling designs significantly reduces alien crosstalk, these length limitations are not applicable to F/UTP cabling. CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

29 F R O M 5 e T O 7 A TIA TSB-155 and ISO/IEC also specify recommended mitigation practices in the event that an installed category 6/class E channel does not satisfy the minimum alien crosstalk levels. Mitigation techniques include using non-adjacent patch panel ports to support the 10GBASE-T application, separating or using improved equipment cords, using F/UTP equipment cords, unbundling cables, reconfiguring cross-connects as interconnects, and replacing category 6/class E components with category 6A/class E A components. Category 6/class E cabling is not recommended for new installations targeted for support of the 10GBASE-T application. The reason for this is that, while field test devices for determining compliance to the new PSANEXT loss and PSAACRF (previously known as PSAELFEXT loss) parameters are just now being introduced to the market, the test methodology remains extremely time-consuming, overly onerous to implement, and may not be fully conclusive. Furthermore, in a majority of installations, alien crosstalk mitigation will be required. Often, the recognized mitigation methods cannot be easily implemented due to existing pathway fill restrictions and the potential need to replace components. In addition, there is no guidance on qualification procedures for large installations or future MAC work. Since the category 6/class E Standard was published in 2002, it is more than halfway through its targeted 10-year lifecycle. Today s cabling specifiers are looking to even higher performing grades of cabling to ensure maximum performance and return-on-investment. CATEGORY 6A/CLASS E A Category 6A/class E A cabling requirements are nearing finalization and were initially developed to address the extended frequency bandwidth and alien crosstalk headroom required to support 10GBASE-T over 100 meters of cabling containing up to four-connectors. Category 6A/class E A cabling delivers positive signal-to-alien crosstalk margin up to 500 MHz and is recommended as the minimum grade of cabling capable of withstanding the rigors the cabling environment and supporting 10GBASE-T when it is time for an application upgrade. Balance requirements for channels and permanent links are also specified for the first time, thereby ensuring better electromagnetic compatibility (EMC) performance than any previous generation of cabling. Performance headroom has been incorporated into all transmission parameters, including power sum alien crosstalk, and both laboratory and field test qualification methods are specified for category 6A/class E A cabling. Average power sum alien crosstalk across all four-pairs is specified for use by the IEEE committee in their channel capacity modeling. It is interesting to note that the term equal level far-end crosstalk loss (or ELFEXT loss) previously used in TIA specifications has been replaced by attenuation to crosstalk ratio, far-end (or ACRF). The intent of this change is for TIA to harmonize with the ISO terminology and more accurately describe the actual test measurement configuration. Category 6A/class E A cabling provides the maximum return-on-investment when the calculations are performed using a 10-year lifecycle. CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

30 F R O M 5 e T O 7 A CLASS F Class F requirements were published in 2002 and describe performance criteria for a fully shielded media type (i.e. cabling with an overall shield and individually shielded pairs). Category F cabling delivers positive attenuation-to-crosstalk margin up to 600 MHz and offers unsurpassed electromagnetic capability (EMC) performance because of its shielded construction. Due to its ease of use, performance headroom, ability to support multiple applications under one sheath, and its specification as the recommended category 7 interface in the ISO Standard, the non-rj style plug and socket interface specified in IEC :2002 is the most commonly specified category 7 connector. This interface is commercially available from multiple manufacturers whose products are interoperable. There is significant evidence that the cabling industry and applications developers are ready to adopt fullyshielded cabling. For example, class F cabling was identified as the copper media of choice in one IEEE new application call-for-interest and the published ISO/IEC application Standard, entitled, A Full Duplex Ethernet Physical Layer Specification for 1000 Mbit/s operating over balanced channels Class F (Category 7 twisted pair cabling), specifies operation over a minimally rated class F channel. It is interesting to note that, although TIA is not actively developing a standard for category 7 at this time, it is acceptable to specify class F cabling in North American markets. The rationale for this is that, in addition to being recognized by BICSI, NEMA, IEEE, and other standards organizations, class F is simply a superset of TIA category 6A requirements. Field test requirements and adapters for class F cabling qualification have been commercially available since The advantage that class F has over other grades of cabling is that it is targeted for support of next generation applications beyond 10GBASE-T. Class F cabling is the only media to have a 15-year lifecycle and class F cabling provides the maximum return-on-investment when calculations are performed using a 15-year lifecycle. CLASS F A Class F A requirements are based upon the existing class F cabling requirements and category 7 non-rj style plug and socket interface. The significant enhancement in class F A specifications is the extension of the frequency bandwidth of characterization from 600 MHz to 1,000 MHz. This enhancement allows class F A cabling to be uniquely capable of supporting all channels of broadband video (e.g. CATV) that operate up to 862 MHz. It is likely that all fully-shielded cabling solutions specified in the near future will be class F A. CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

31 F R O M 5 e T O 7 A APPLICATIONS SUPPORT Table 3 summarizes cabling types capable of supporting commonly specified applications over 100-meter, four-connector topologies. TABLE 3: APPLICATIONS CHART CATEGORY/5E CLASS D CATEGORY 6/CLASS E CATEGORY 6A/CLASS E A CLASS F CLASS F A 4/16 MBPS TOKEN RING l l l l l 10BASE-T l l l l l 100BASE-T4 l l l l l 155 MBPS ATM l l l l l 1000BASE-T l l l l l TIA/EIA-854 l l l l 10GBASE-T l l l ISO/IEC l l BROADBAND CATV l PERFORMANCE COMPARISON CHART: Table 4 provides comparative channel performance data at 100 MHz for category 5e/class D, category 6/class E, category 6A/class E A, class F, and class F A channels. Where there is a slight difference between TIA and ISO performance limits, ISO performance limits are indicated in parenthesis. TABLE 4: INDUSTRY STANDARDS PERFORMANCE COMPARISON AT 100 MHZ FOR CHANNELS Category 5e/Class D Category 6/Class E Category 6A/Class E A Class F Class F A Frequency Range (MHz) ,000 Insertion Loss (db) / NEXT Loss (db) PSNEXT Loss (db) ACR (db) PSACR (db) ACRF 1 (db) / PSACRF 2 (db) / Return Loss (db) PSANEXT Loss (db) n/s n/s 60.0 n/s 67.0 PSAACRF (db) n/s n/s 37.0 n/s 52.0 TCL (db) n/s n/s ELTCTL 3 (db) n/s n/s 0.5/0 0 0 Propagation Delay (ns) Delay Skew (ns) Specified as ELFEXT loss for category 5e/class D and category 6/class E. 2 Specified as PSELFEXT loss for category 5e/class D and category 6/class E. 3 ELTCTL is specified at 30 MHz. CONNECTING THE WORLD TO A HIGHER STANDARD W W W. S I E M O N. C O M

32 D ATA C E N T E R C A B L I N G Why Category 6 Should Not be Specified for 10Gb/s A recent report 1 by the industry market research firm IDC provided the recordbreaking news: more than one million 10 Gigabit Ethernet ports were shipped during the 2nd quarter of A likely bet is that the majority of these switches are being deployed in the data center. As 10GBASE-T network equipment becomes increasing available, data center decision makers will want to take advantage of the cost savings, convenience, and flexibility provided by deploying 10 Gb/s technology over balanced twisted-pair copper cabling. While it is true that category 6 cabling can provide limited support of 10GBASE-T in some environments, the reality is that there are some very compelling reasons to specify category 6A or higher cabling in a new 10 Gb/s-ready data center. 8 Standards recognize category 6A as the minimum grade of cabling for data centers TIA, ISO/IEC, and other telecommunications Standards organizations have developed Standards that address cabling system design and installation in the data center environment. The message of these Standards is clear: the minimum grade of cabling to be deployed in the data center is category 6A. The working draft of ANSI/TIA-942-A 2 states that category 6A is the recommended grade of horizontal and backbone cabling to install in new data centers. ISO/IEC explicitly states that main distribution and zone distribution cabling systems supporting data centers shall be designed to provide a minimum of class E A (equivalent to TIA category 6A) channel performance. 8 Category 6 support of 10GBASE-T is uncertain Several published industry guidelines (e.g. TIA TSB-155-A 4 and ISO/IEC TR ) are available to assist in qualifying the capability of an existing category 6 cabling plant to support 10GBASE-T. These guidelines were not intended for newly-installed cabling. According to guidelines, category 6 cabling less than 37 meters (121 feet) should support the 10GBASE-T application and cabling between 37 meters and 55 meters (180 feet) should support the application depending upon the alien crosstalk environment. However, there is no 10GBASE-T application support assurance over short runs of category 6 because alien crosstalk is highly dependent on cable density. The only way to ensure compliance to guidelines such as TSB-155-A and ISO/IEC TR is to perform complicated alien crosstalk field tests on every channel. This testing can be extremely time-consuming and may not be fully conclusive. In a majority of data center installations, alien crosstalk mitigation will likely be required. The recognized mitigation methods cannot be easily implemented due to existing pathway fill restrictions and the potential need to replace links or components. Finally, there is no guidance on qualification procedures for large installations or future MAC ( moves, adds, and changes ) work. The added cost and uncertainty associated with alien crosstalk qualification testing of category 6 cabling makes category 6A systems a much more desirable solution for new 10 Gb/s-ready data centers. 8Category 6 running 10Gb/s should not be used in the same pathways as category 6A UTP Emerging industry guidance on pathway separation (e.g. TIA TSB ) unequivocally states that category 6 UTP cabling transmitting 10GBASE-T signals should not be placed unbundled, in adjacent bundles, or in the same bundle as category 6A UTP cabling transmitting 10GBASE-T signals. TIA TSB-190 also reaffirms TIA s position that category 6A cabling should be used for all new installations targeted for support of 10GBASE-T. 8There are no applications under development for category 6 Both TIA and ISO state that the cabling systems specified in their Standards are intended to have a useful life in excess of 10 years. Since the category 6 and class E cabling Standards were published in 2002, these systems are already beyond the halfway point of their targeted lifecycle. Furthermore, applications development groups such as IEEE or ATM are not investigating the development of new Ethernet or other data transmission solutions for deployment over category 6 cabling.

33 Why Category 6 Should Not be Specified for 10Gb/s D ATA C E N T E R C A B L I N G 8Category 6 UTP cannot support a full 100 meter 10GBASE-T channel, limiting design flexibility Category 6A and 7A can support a full 100 meter channel and potentially longer. Siemon is working with Aquantia, a leading 10GBASE-T chip manufacturer to test their shielded 6A and 7A cabling systems in extended channel distances beyond 100 meters 7 - instead of using category 6 UTP and shortening it. Shortening channels to use category 6 for 10GBASE-T may restrict equipment placement and require the addition of patching zones or switches, resulting in added connectivity, equipment and power cost. 8Category 6 UTP cannot support power-saving short reach mode (aka data center mode) Short reach mode, per the IEEE 10GBASE-T standard can reduce power consumption by approximately 1W per port when using shorter (30m or less) category 6A or higher cabling channels. Category 6 cabling cannot take advantage of this power savings mode, therefore making it a higher cost and less environmentally friendly option. 8Cables with reduced diameter conductors cannot dissipate heat as well as category 6A or higher systems Data center temperatures are increasing. ASHRAE recommendations are up to 81F/27Cº. Cable insertion loss increases as cabling temperature increases. In data centers, the majority of cabling is at the rear of server cabinets where the heat is the greatest. The increased current levels of evolving PoE+ applications also generate more heat, further compounding these temperature issues. TIA and ISO specify a temperature dependent de-rating factor used in determining horizontal cable length at temperatures above 20Cº (68F). Horizontal cables having reduced diameter conductors will be further limited in distance due to a higher temperature de-rating factor compared to category 6A and especially compared to shielded category 6A and higher cabling. References 1- Worldwide Ethernet Switch and Router 2Q10 Market Share Update, Doc # , IDC, August ANSI/TIA-942-A, Telecommunications Infrastructure Standard for Data Centers, draft 2.0, pending publication 3 - ISO/IEC 24764, Ed. 1.0, Information technology Generic cabling for data centers, April TIA TSB-155-A, Guidelines for the Assessment and Mitigation of Installed Category 6 Cabling to Support 10GBASE-T, March ISO/IEC TR 24750, Information technology Assessment and Mitigation of Installed Category 6 Cabling to Support 10GBASE-T, July TIA TSB-190, Guidelines on Shared Pathways and Shared Sheaths, draft 2.0, pending publication 7 - Aquantia Press Release, July ASHRAE (22-23C) Siemon Asia Pacific Headquarters Shanghai, China Tel: (86) Siemon CASA Headquarters Central & South America Bogota, Colombia Tel: (571) Siemon EMEA Headquarters Europe, Middle East & Africa Chertsey Surrey, England Tel: (44) (0) Siemon Brazil Sao Paulo, Brazil Tel: (55) Siemon North America Headquarters Watertown, Connecticut Tel: (1) FLR_No_10G_Cat6 9/10 Visit our website at for detailed global office contact information

34 Short Length 26 AWG Data Center Solutions Equal Long Term Risks Convergence, virtualization, and an improving economy are fueling tremendous data center growth. As would be expected, the increasing number of ports and congestion in today s data centers presents a new set of cabling challenges including: Managing air flow for optimum thermal performance Maintaining proper pathway fill requirements Supporting advanced applications such as 10GBASE-T and PoE Plus Unfortunately, a recent trend in the industry is to respond to these challenges by deploying twisted-pair cables constructed from 26 AWG conductors over a restricted length channel topology. The trend is based on the idea that these cables reduced outside jacket diameter will help alleviate thermal and pathway fill issues. The primary concern with this practice is the fact that these reduced-length systems are not Standards compliant. Cables with 26 AWG conductors do not comply with any TIA or ISO/IEC Standard for horizontal cable requirements, all of which specify a minimum of 24 AWG (0.5mm) conductors. Any claim that these cables are category 6A, 6, or 5e compliant is a violation of the Uniform Commercial Code. As a result of the deficiencies imparted by the use of these smaller diameter conductors, the length of channels must be shortened (typically to 70 meters) to satisfy maximum channel insertion loss requirements. While this approach is commonly justified by the rationale that 100 meter topologies are not often deployed in data centers, there are multiple long term risks associated with specifying a cabling system that fails to meet one of the most fundamental mechanical construction requirements. 8 Risk: Support of Future Applications is Unknown Should a future application be developed for operation over category 6A cabling, there is no assurance that channels constructed from 26 AWG horizontal cables will support it. 8 Risk: Power Delivery Applications Generate Excessive Heat Horizontal cables constructed from 26 AWG conductors have significantly higher per unit length direct current or dc loop resistance than the maximum 0.25Ω per meter requirement specified by TIA and ISO Standards. These cables can exhibit dc loop resistance as high as 0.29Ω per meter. Depending upon bundle size, this increased resistance may result in a temperature rise in excess of the maximum 10 C allowed by IEEE 802.3at for PoE Plus deployment; calling into question the ability of these solutions to adequately support power delivery. Excessive heat not only adversely affects the operation of electronic equipment, but can result in premature aging of the dielectric materials that are used in the cable jacket and conductor insulation. As targets for future power delivery applications increase from the PoE Plus level of 30 watts to proposed values as high as 100 watts, compliance to TIA and ISO Standards requirements for per unit length dc loop resistance becomes extremely critical to avoid excessive heat generation. 8Risk: Reduced Flexibility for Future Growth: The challenges that data centers are facing today are fueled by growth, but short length channel topologies ultimately restrict flexibility to accommodate data center expansion in the future. This is counterintuitive. Standards specified cabling topologies provide the most flexibility for growth and support of new applications. 8Solution: Reducing overall cable diameter is not the only way, nor the best way, to manage airflow and maintain proper pathway fill in the data center. These issues can be effectively addressed without the specification of noncompliant, reduced-length cabling systems that compromise applications support and future growth. Data center products such as Siemon s VersaPOD cabinet and cable management solution maximize air flow through specialized design features that include perforated front and rear doors, open base construction, air flow management between cabinets, and provisions for roof mounted cooling fans and additional accessories such as brush guards, blanking panels, and grommets that promote proper air flow and temperature control. VersaPOD also features an array of integrated horizontal and vertical cable management options that support high cable capacity in addition to a concealable pathway for cable routing and slack management. With so many smart and flexible options available, it just doesn t make sense to take on the long term risks associated with short length cabling. FLR_LngTerm Risk_B 11/10 Siemon Asia Pacific Headquarters Shanghai, China Tel: (86) Siemon CASA Headquarters Central & South America Bogota, Colombia Tel: (571) Siemon EMEA Headquarters Europe, Middle East & Africa Chertsey Surrey, England Tel: (44) (0) Siemon Brazil Sao Paulo, Brazil Tel: (55) Siemon North America Headquarters Watertown, Connecticut Tel: (1)