10 Factors to consider when choosing a cabinet or rack

The sheer number and different types of cabinets and racks can make choosing the right one for your data center a daunting task. But, if you consider your requirements one at a time, you can zero in on the right cabinet or rack for your application.

A cabinet is an enclosure with four rails and a door (or doors) and side panels. A rack is an open, freestanding 2- or 4-post frame that doesn’t have doors or sides. The decision on whether to use a cabinet or rack depends on a number of factors.

1. Equipment
Before you choose a cabinet or rack, you need to determine what equipment you’re planning to house. This list can include servers, switches, routers, and UPSs. Consider the weight of your equipment as well. The extra stability of a cabinet might be important if you’re installing large, heavy equipment like servers. An open rack is more convenient than a cabinet if you need frequent access to all sides of the equipment.

2. Environment
With the open design, racks are a good choice in areas where security isn’t a concern such as in locked data centers and closets. And racks typically cost less than cabinets.

Cabinets, on the other hand, protect equipment in open, dusty, and industrial environments. Aesthetics can be a factor too. Will customers or clients see your installation? A cabinet with a door looks much neater than an open rack. When you’re trying to create a professional image, everything counts.

3. Ventilation
If your equipment needs ventilation, a rack offers more air circulation than a cabinet. Even if your cabinet is in a climate-controlled room, the equipment in it can generate a lot of heat. The requirements for additional airflow increase as more servers are mounted in a cabinet. Options to improve airflow include doors, fans, and air conditioners.

4. Size
Width: The width between the rails in both cabinets and racks is 19 inches with hole-to-hole centers measuring 18.3 inches. But there are also cabinets and racks with 23-inch rails. Most rackmount equipment is made to fit 19-inch rails but can be adapted to fit wider rails.

Rack Units: One rack unit (RU or U) equals 1.75″ of vertical space on the rails. A device that’s 2U high takes up 3.5 inches of vertical rack space. Rack units are typically marked on the rails. The number of rack units determines how much equipment you can install.

Depth: Cabinets and four-post open racks come in different depths ranging anywhere from 24″ to 48″ to accommodate equipment of varying sizes, particularly extra-deep servers. The rails on some cabinets and 4-post open racks are also adjustable to different depths.

When you consider the width, height, and depth of a cabinet or rack, clarify whether they are inside or outside dimensions.

5. Weight
Cabinets and racks vary in terms of the amount of weight capacity. Some cabinets can hold 1,000 pounds or more. Carefully consider the weight of your equipment and decide where you want to mount it before choosing a cabinet or rack.

6. Rails
The vertical rails in cabinets and racks have holes for mounting equipment. Two post racks typically have threaded 12-24 or 10-32 tapped holes. 4-post racks and cabinets often have M6 square holes for mounting servers.

7. Moisture, dust, shock, vibration
When housing electronic components outside of a protected data center, look for a cabinet with a NEMA (National Manufacturers’ Association) rating. NEMA standards are designed for corrosion resistance, protection from rain, submersion, liquids, dust, falling objects, and other hazards. There are also NEBS-Telcordia standards for protection against seismic activity, shock, and vibration. Cabinets and racks can also be bolted to the floor for extra stability.

8. Power provisioning
There are multiple options for powering rackmounted equipment. Power strips mount can be mounted vertically or horizontally. Power Distribution Units (PDUs) and Power Managers have additional capabilities such as remote management and metering. Uninterruptible power supplies (UPSs) typically mount in the bottom of a cabinet or rack because of their weight.

9. Cable management
Most cabinets and racks have built-in cable management troughs and cable rings for routing cable. For more information on cable management, see 9 Ways to Improve Data Center Cable Management.

10. The extras
The type of shelving you choose depends on the equipment you plan to mount. There are multiple options: solid, vented, stationary, and pull-out shelves. And there are shelves built to hold specific pieces of equipment, such as servers or keyboards. Other extras include fans, waterfall brackets, and grounding bars.

Credit card liability shift leads retailers to PoS upgrade

The U.S. is the last major market in the world to use magnetic-stripe swipe-and-sign credit card systems. These legacy credit cards are also one of the big reasons why almost half of the world’s credit card fraud happens in America although the U.S. accounts for only a quarter of all credit card transactions. The Target breach affected the credit card information of about 40 million people and the personal data of up to 70 million people.

The rest of the world uses EMV (Europay, MasterCard, and Visa) credit cards. The cards have a chip embedded in them that stores customer data. They are considered much safer than magnetic stripe cards and are much more difficult to hack. The U.S. has been years behind the rest of the world in adopting chip-embedded credit cards. But that is changing.

The push is on in the U.S. to get everyone switched over to the EMV system by October 2015. That’s when there will be a big shift in credit card fraud liability.

After the October deadline, if a retailer is still using the old swipe system, the liability for any fraudulent transactions shifts from the financial institution to the merchant if the consumer is using a chip card.

The shift also involves the opposite scenario. If a retailer has the new terminal, but the bank hasn’t issued a new chip-embedded card, the liability for fraud rests with the bank.

Many U.S. banks, credit unions, and credit card issuers have already issued chip-enabled cards or are in the process of changing over to them. The big question is will retailers be ready?

New PoS terminals
Currently, consumers swipe legacy magnetic-stripe credit cards at point-of-sale (PoS) terminals. The new chip-enabled cards require different processing terminal called a “chip-and-dip.” Instead of swiping, the consumer inserts (or “dips”) the card into the EMV processor. This requires retailers to invest in new equipment and, possibly, new infrastructure to support the processors.

Some retailers, such as Walmart, have already installed checkout terminals that can process the chip-and-pin cards. Other retailers are in the process of installing the new terminals.

One national retailer, a longtime Black Box customer, is using this opportunity to upgrade its infrastructure from the data center to the IDF at the front-line cash registers. The upgrade includes installing new horizontal CATx cable, patch cables, patch panels, and secure wallmount cabinets.

Depending on the network (retail or not), other extension and IDF upgrades can include:

• Running fiber cable beyond the 100-meter copper limit and for EMI/RFI immunity.
• Using small, locking enclosures, including climate-controlled cabinets.
• Saving space at crowded registers with right-angle patch cables.
• Securing network connections with lockable patch cables.

For the key structured cabling standards, you may be interested in this white paper: Structured Cabling Standards and Organizations.

How to choose and use PVC and plenum cable

Deciding between PVC and plenum cable is very important because the type of cable you choose can have critical consequences.

The difference between PVC and plenum is the type of jacket that surrounds the cable. Whether you choose PVC- or plenum-jacketed cable depends on where you are going to use the cable. Most of the time, the type of cable depends on your local building codes and/or the age and design of the building.

What’s plenum?
First, let’s define plenum. The term plenum is an HVAC term. A plenum space is the part of a building, or pathway, designed for circulating heated and cooled environmental air and for return airflows. In most buildings, the space above the ceiling or below a raised floor is used for HVAC air. Duct work is also considered a plenum. A plenum ceiling is where the air is forced through the ceiling rather than being ducted.

Plenum spaces are air tight and usually have a greater atmospheric pressure and a greater oxygen content. Plenums can be particularly dangerous in case of fire. The oxygen can turn a small spark into an out-of-control fire. And because the air is forced through the plenum, smoke and fire can very quickly travel throughout the building. If cable is run through a plenum, it must be a plenum-rated cable if no conduit is used.

The importance of properly cleaning fiber during termination – Part 3

This is part three of a three part series on fiber cleaning. For part two, click here.

From the August, 2014 Issue of Cabling Installation & Maintenance Magazine
By Sean Sheedy

Unless you are working in the tropics, never select a water-based fiber cleaner. It is very slow to dry and will freeze in cold weather.

One excellent characteristic of IPA is its ability to dissipate static. With a static charge, particulate will bind to surfaces surprisingly aggressively. For example, a large 500-micron (μ) particulate takes twice the force of gravity (2 G’s) of “scrubbing” (mechanical action) to remove. But a 5-μ flake of solid residue takes 20,000 G’s to break loose from the intermolecular grip the particulate has on the substrate. How do you get 20,000 G’s of scrubbing force inside an LC connector? You don’t. So solvents help solve the problem by neutralizing the static charge.

In the past decade there have been at least two studies looking at static on endfaces. iNEMI’s results were presented in “Accumulation of Particles Near the Core During Repetitive Fiber Connector Matings and Dematings,” at NFOEC in 2007. And during the development of the IPC-8497-1 standard, 18 researchers worked on the problem of static. Their findings were presented in “Cleaning Methods and Contamination Assessment of Optical Assembly,” at NFOEC in 2006. This research clearly observed that wiping an endface with a dry wipe did not dissipate the static on the endface, and indeed may have added a triboelectric charge to the endface, which made the endface even more prone to attracting particulate. This problem was eliminated with a wet-dry cleaning process, in which a cleaning fluid was used to dissipate the static, and then a dry wipe was used to polish away any residual fluids. This is an excellent procedure and should be used by everyone in the fiber industry.

9 Ways to improve data center cable management

Cable management is one of the most important aspects of data center design. Last week, Processor magazine interviewed our Wire and Cable Product Engineer, Steve Molek, on ways to improve data center cable management. Below is the transcript from that interview.

Processor: Do you feel data centers have made inroads in recent years in terms of cable management, neatness, and organization? If so, what do you attribute the improvement to?

Steve: Yes. Equipment overall has become smaller, thus allowing more electronics in a cabinet.  Because of this, installers must pay closer attention to cable management, otherwise they can lose the valuable space gained to the additional cables.

Processor: In what areas do data centers still falter in terms of cable management? Where can they still improve?

Steve: Old habits die hard. In the past, cable management was not a focus, since data centers used a more “centralized design.” Today, cable management should follow a more structured design, similar to horizontal cable runs.

Also, one of the simplest ways to organize your data center is by using colored patch cables and bulk cables. Colored cable has been around a long time, and coloring the security system differently from accounting or customer service lines, for example, is a great way to visually identify different runs of cable at a glance. We offer the same kind of coloring in our fiber patch cable lines as well, which is not as common in the industry.