The data center is the most critical resource of any business, providing the means for storage, management and dissemination of data, applications and communications. Within the data center, large amounts of information are transmitted to and from servers, switches, routers and storage equipment via the physical layer’s low-voltage cabling infrastructure. The design and deployment methods of the cabling infrastructure have a direct impact on data center space savings, proper cooling and reliability and uptime.
Space Savings
Business environments are constantly evolving, and as a result, data center requirements continuously change. Providing plenty of empty floor space when designing your data center enables the flexibility of reallocating space to a particular function, and adding new racks and equipment as needed.
As connections, bandwidth and storage requirements grow, so does the amount of data center cabling connecting key functional areas and equipment. Maximizing space resources is one of the most critical aspects of data center design. Choosing the right mix of cabling and connectivity components can have a direct impact on the amount of real estate required in your data center. Fundamentally, you cannot use the same cabling components designed for low-density LANs and expect them to perform to the level required in a data center. To properly design your data center for space savings:
• Ensure ample overhead and underfloor cable pathways for future growth.
• Select high-density patching solutions that require less rack and floor space.
• Consider higher port-density solutions like 12-fiber MPO cables and cassettes.
• Look for smaller diameter cables that take up less pathway space.
Expanding the physical space of a data center requires construction, movement of people and equipment, recabling and downtime. Expansion can cost more than the original data center build itself. Given these consequences, properly designing the data center for space savings at the start is essential. TIA-942 Telecommunications Infrastructure Standard for Data Centers, which was published in 2005 and specifies requirements and guidelines for data center infrastructures, covers cabling distances, pathways, site selection, space and layout. This standard is a valuable tool in designing your data center infrastructure for maximum space savings.
Proper Cooling
The reliability of data center equipment is directly tied to proper cooling. Servers and equipment are getting smaller and more powerful, which concentrates an enormous amount of heat into a smaller area. Proper cooling equipment is a must, as well as the use of hot aisle/cold aisle configuration where equipment racks are arranged in alternating rows of hot and cold aisles. This practice, which is recommended in the TIA-942 standard, allows cold air from the cold aisle to wash over the equipment where it is then expelled out the back into the hot aisle (see Figure 1).
Figure 1: Hot Aisle/Cold Aisle Cooling
Good cable management solutions are also necessary for proper cooling. Cables that are not properly stored and organized can block air inlets and exits, which can raise the temperature of switches and servers. Other considerations for cooling include the following:
• Increase airflow by removing obstacles to air movement, blocking unnecessary air escapes, and/or increasing the height of the raised floor.
• Spread equipment out over unused portions of the raised floor, space permitting.
• Use open racks instead of cabinets when security is not a concern, or use cabinets with mesh fronts and backs.
• Choose components that manage fiber overhead, reducing the need to store it in the raised floor and helping to increase airflow.
• Use perforated tiles with larger openings.
Reliability & Uptime
When employees and customers are unable to access the servers, storage systems and networking devices that reside in the data center, your entire organization can shut down, and millions of dollars can be lost in a matter of minutes. With 70 percent of network downtime attributed to physical layer problems, specifically cabling faults, it’s paramount that more consideration is given to the cabling infrastructure design and deployment.
As information is sent back and forth within your facility and with the outside world, huge streams of data are transferred to and from equipment areas at extremely high data rates. The low-voltage cabling deployed in the data center must consistently support the flow of data without errors that cause retransmission and delays. A substandard performing data center can be just as costly and disruptive to your business as total downtime.
Because networks expand and bandwidth demands increase, the cabling should be selected to support current needs while enabling migration to higher network speeds. In fact, the cabling chosen for the data center should be designed and implemented to outlast the applications and equipment it supports by at least 10 to 15 years. With 10 Gigabit Ethernet already a reality, that means implementing the highest-performing cable available such as augmented category 6 copper cabling and laser-optimized 50µm multimode fiber. These types of copper and fiber cabling will support bandwidth requirements for the future and ensure reliability of your data center for many years to come.
The protection of cabling and connections is a key factor in ensuring data center reliability and uptime. When cabling is bent beyond its specified minimum bend radius, it can cause transmission failures, and as more cables are added to routing paths, the possibility of bend radius violation increases (see Figure 2). The separation of cable types in horizontal pathways and physical protection of both cable and connections should also be implemented to prevent possible damage.
Figure 2: Care must be taken to avoid violating minimum
bend radius when adding fibers
Manageability is also key to maintaining uptime, and it starts with strategic, unified cable management that keeps cabling and connections properly stored and organized, easy to locate and access, and simple to reconfigure. Infrastructure components that offer proper cable management reduce the time required for identifying, routing and rerouting cables during upgrades and changes, thereby reducing downtime.
The use of a central patching location in a cross-connect scenario is the optimum solution for enhanced manageability in the data center, providing a logical and easy-to-manage infrastructure whereby all network elements have permanent equipment cable connections that once terminated, are never handled again. In this scenario, all modifications, rerouting, upgrades and maintenance activities are accomplished using semi-permanent patch cord connections on the front of the cross-connect systems (see Figure 3).
Figure 3: Interconnect vs. Cross-Connect
To improve the reliability and uptime of the data center:
• Choose the highest performing cabling and connectivity backed by a reputable manufacturer and engineered for uptime with guaranteed error-free performance.
• Select components that maintain proper bend radius, efficiently manage cable slack, and provide separation of cable types and physical protection.
• Deploy common rack frames with ample cable management that simplify cable routing and ensure paths are clearly defined and intuitive to follow.
• Use connectivity components that ensure connectors are easily defined and accessed with minimal disruption to adjacent connections.
• Deploy plug-and-play cabling solutions for faster configuration and upgrades.
• Use a central patching location in a cross-connect scenario.
Summary
The enterprise network is made up of layers with each layer supporting the one above it. When transmitting information across the network, control starts at the application layer and is moved from one layer to the next until it reaches the physical layer at the bottom where low-voltage cabling and components provide the means for sending and receiving the data. Since the total cost for low-voltage cabling components of the physical layer is but a fraction of the entire data center cost, decisions for selecting that physical layer are often taken lightly. But the fact remains that the cabling infrastructure is the core foundation upon which everything else depends – failure at the physical layer affects the entire network.
By recognizing the value of the data center cabling infrastructure, you can ensure that employees and customers have access to the servers, storage systems and networking devices they need to carry out daily business transactions and remain productive. Selecting fiber and copper cable, connectivity and cable management components that work together to satisfy space savings, reliability and uptime requirements lower the total cost of ownership. This is the ultimate means to a thriving data center and overall successful business.
About the Author
John Schmidt is the Senior Product Manager for Structured Cabling at ADC. John has been with ADC for 10 Years in a variety of design engineering and product management roles. He is the author of several articles, white papers, and presentations related to the design of telecommunications and data networks. John has a Bachelor of Science degree in Engineering from the University of Minnesota, and has 10 patents for telecommunications and network equipment design.
About ADC
Founded in 1935, ADC provides the connections for wireline, wireless, cable, broadcast and enterprise networks around the world. ADC’s network infrastructure equipment and professional services enable high-speed Internet, data, video, and voice services to residential, business, and mobile subscribers. The company sells products and services in more than 130 countries. Today, ADC is focused on serving the converged network, carrying simultaneous voice, data, and video services over wireline and wireless connections via products engineered for uptime. For more information about ADC, call 1-800-366-3891 or visit www.adc.com.
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