Too often, the cable assemblies used to interconnect equipment in the data center environment are considered commodity products and not given much thought. However, cables assemblies are an important part of your network, and there are differences among the myriad of cabling choices available on the market. Buy cheap and beware of the consequences – data errors, slow speeds, and hours upon hours of IT time spent searching for the offending cable. These issues can be avoided by choosing the right cables to begin with.
Here are six things to consider:
1. Compatibility Equipment built to industry standards are intended to be interoperable with other standards-based devices – but beware. That bargain priced, no-name brand cable you have in the drawer may look like it meets a standard, such as InfiniBand™ FDR, but the internal electronics may actually be specific to an OEM, which could mean that it is not compatible with your piece of equipment. Consult the device’s manual for the specified I/O cable. You may need to buy the cable from the same manufacturer or an authorized distributor to prevent voiding the warranty or creating technical support issues. If you are assembling your own computing equipment, make sure your cables are not specific to a particular OEM’s products by carefully reading the specs and consulting your distributor’s technical service engineers.
2. Performance Cables can’t speed up your system, but they can certainly slow it down. Make sure your cable can support the speed you need. Industry standards prescribe performance – for instance, a cable marked SFP+ should be capable of supporting 10 Gigabit Ethernet.
Another aspect of performance to consider is: How will the cable perform when routed? Because of the precise conductor geometry required to maintain signal integrity, many cables have a less-than-generous prescribed bend radius. If an installer bends it beyond its limit, cable performance can be compromised. Choosing a cable that can be bent and folded without significantly affecting signal performance, such as the 3M™ Twin Axial Cable, can help ensure that the cable will perform at a high level after it’s deployed.
3. Routability Ease of routing is an issue, especially in horizontal runs, where copper cable assemblies are generally used to interconnect servers within the rack. Save space by using cables that can still perform well if bent or folded. Traditionally, round twin axial Cables are used within the rack. These cables typically need a generous bend radius. Bending them too much can distort the precise cable geometry needed to maintain impedance control, degrading signal performance. On the other hand, the 3M Twin Axial Cable’s innovative construction allows it to be tightly bent and folded – even multiple times – without significantly affecting signal performance. A small bend radius means it can be routed to consume less real estate in the rack and can be routed out of the way of air flow channels, potentially reducing cooling costs.
3M Twin Axial Cables can also aid in designing high-density modular data center designs. For instance, Nor-Tech, a leading manufacturer of HPC solutions, used the cables in a sealed, portable data center solution for a client who needed a custom super computer that would fit in tight quarters. Nor-Tech designed a compact, sealed, portable data center solution comprised of 1,300 CPU cores, with InfiniBand™ cables connecting each compute core. Air flow within the cooled system was critical to keep it performing to its highest capability. Nor-Tech was able to route the 3M Twin Axial Cable Assembly for SFP+ Applications away from air flow channels, helping the company’s engineers create a highly compact system that would not overheat.
Photo courtesy of Nor-Tech
4. Energy Efficiency Active Optical Cables (AOCs) have become a common sight in data centers due to fiber’s ability to deliver high-speed data rates over long reaches. Be aware that these cable assemblies contain a transceiver on each end that performs the electrical-optical-electrical conversion, and those transceivers consume power – up to one-third of the power used by a 10 Gbps port, in fact. Therefore, choosing a low-power AOC is essential to creating an energy efficient data center.
Interconnect suppliers have toiled to bring down power consumption of AOCs. Yet, even within the low-power category, power consumption varies from product to product. Compare the power usage specs of AOC products in order to make sure you are purchasing a cable assembly that will help maximize energy efficiency. 3M offers some of the lowest power AOCs available on the market for QSFP+ and SFP+ applications in order to help data centers reduce consumption and cost.
5. Reliability As data rates increase and customers become less tolerant of errors and failure, the reliability of all equipment becomes more critical. Like anything else, with cables, you get what you pay for. Look for a trusted cable manufacturer with expertise in the interconnect space and that backs up its products with technical service and warranties. Go to the cable manufacturer’s website and download the very latest supporting technical documentation and reference materials. Authorized distributors are another good source of information. Above all, choose a cabling vendor that can show test data that confirms product reliability and that has a proven track record of producing robust products.
6. Total Cost of Ownership If you still insist on buying the cheapest cable available, consider this: The price of the cable itself provides only part of the cost picture. Like any piece of hardware, determining the true cost must include an evaluation of its associated operating expense. One important aspect of total cost of ownership (TCO) to consider is ease of maintenance. For instance, in the Nor-Tech case, its client required clearance between the nodes so that frequent maintenance and changes could be performed unencumbered. When a technician has to maneuver though a “rat’s nest” of cabling in order to perform a task, unproductive time on the clock ticks away. That’s another reason Nor-Tech chose the 3M Twin Axial Cable. The cable’s ability to be bent at sharp angles allows it to be neatly folded out of the way for ease of maintenance.
Photo courtesy of Nor-Tech
Making informed choices about cabling can make the difference between a system that performs reliably and one prone to errors. These six simple pointers will help you ask the right questions of your provider so your manager doesn’t have to.
Learn more at 3m.com/getconnectedfaster