Data centre connectivity optimization

By William L. DiBella

Uptime! Downtime! The foresight in managing risk is a critical element in operating a Data Centre. A tremendous amount of money and time is spent on power and cooling solutions, software, and redundancy, to include hardware and backup power configurations.

“The choices you make today will determine the integrity and sustainability of your infrastructure tomorrow.”
-William L. DiBella

If the Data Centre is the body, the arteries which sustain life consist of the physical layer connectivity components, which are very often overlooked and taken for granted.  These components are crucial in keeping the Data Centre operational, efficient, and manageable, providing the pathway to a dynamic environment. , and easily adapting to technological changes and upgrades which result in a lower total cost of ownership (TCO).

A combination of customization, product definition, quality, and best practices will augment and enhance optimization in the area of infrastructure connectivity.  As 40 Gig and 100 Gig parallel fibre optic solutions are implemented within the Data Centre, the physical layer infrastructure composition will become one of the primary determining considerations with regards to increased bandwidth and speed availability.

"Interestingly enough, the cost of obtaining an optimal position within the physical layer infrastructure  will not add any cost to the infrastructure but will actually lower costs over time."

The best approach to achieve optimization is to start with well defined purchase specifications of the vital infrastructure components.  Listed below are some of the significant components and associated best of breed attributes that should be considered for inclusion in the specifications for optimization.

Cabinetry does not have to be a continuous source of cost or change. Newer offerings incorporate a telescoping design with dynamically adjustable depths enabling hardware changes on the fly. To illustrate, a cabinet with a depth of  36 inches may be expanded to a depth of 42 or 48 inches to accommodate deeper equipment.  Cabinets are now offered with door management systems that provide added flexibility.  The doors may either be opened individually, or all doors may easily be slid and housed in an end bay system.  By opening up the entire cabinet in a manner similar to an open relay rack, moves, adds, and changes are easily accomplished in timely manner.

Cabinets offering integrated horizontal, vertical, and above the floor front-to-rear cable management pathways allow jumpers to be run above the raised floor. Proper cable management  removes air flow obstruction lowers power and cooling cost, increases cable management ease, and reduces installation time and cost. Mounting switches in the same cabinet housing fibre optic patch panels may reduce the number of trunk cables needed, allowing replacement with short lower cost jumpers.

Fibre Optic Patch Panels built with front access may reduce floor space requirements and reduce the amount of Cabinets required.  This design allows for the installation of patch panels on the front and rear of the cabinet, effectively doubling the fibre optic channel capacity in each cabinet bay.

Fibre Optic Connectors, Couplers, and Adapters are the critical alignment components of the fibre optic infrastructure, producing optimal signal strength and performance for data transmission (especially at higher speeds).  To achieve superior alignment and optimal signal strength at 10 Gig, 40 Gig, and 100 Gig, all multi-mode fibre optic cable terminations (connectors) should be constructed with single-mode quality ferrules.  This will ensure    optimum throughput for high speed applications.  All multimode patch panel couplers and adapter alignment sleeves should also be single-mode quality with diagonal sleeve construction to ensure optimal signal strength and alignment.  An added benefit of installing single-mode couplers and adapters in patch panels is the provision of an easy migration to single-mode cabling extending the life cycle of infrastructure components. A good example of this premise is the introduction of enhanced multi-mode ferrules for MTP ribbon array terminations as well as enhanced LC multi-mode ferrules.

On fibre optic connectors the use of single-body or uni-boot construction in conjunction with DFX style fibre cable in place of zip cable construction results in improved cable management. This is due to the smaller cable diameter, and the resultant higher density connectivity in patch panels and cabinets.  Single-body connectors also contribute to lower power and cooling cost due to increased air flow.

Secured LC connectors offer the following advantages to keyed LC connectors:

1)    The connectors may not be removed without the proper removal key, preventing interruption of critical data

2)    Two levels of authorization via the utilization of  both color coded and master removal keys

3)    Secure connectors mate with existing patch panels and hardware, keyed connectors do not

Fibre Optic Trunk Cables and Jumpers are now available in Bend Insensitive Fibre (BIF) construction, also referred to as "Bend Tolerant Cable".  For multi-mode cable the recommended BIF cable bend rating is 7.5mm.  All single-mode BIF cables are 5.0mm rated. The advantages of  BIF are improvement in bend performance, and the fibre is easier to handle and install.  BIF offers increased protection against poor installation practices and errors to include cable ties that are installed too tight, fibre that is caught in cabinet doors, or fibre incorrectly installed in conveyance tray.

Looking forward to the implementation of 40 Gig and 100 Gig solutions SAN (Storage Area Networks) cabling should possess a minimum rating of OM3, equating to 300 meters for 10 Gig applications and 100 meters on 40 Gig and 100 Gig installs.  On longer cable runs for 10 Gig (up to 550 meters) use O4 rated fibre, which will be rated at 150 meters for parallel optics infrastructures.

Trunk cables constructed with integrated sub-unitized breakouts provide better protection (especially at the ring cut area) over traditional lose tube configurations, and add flexibility to change the breakout length on site, if needed.

This design enables the end user to retain the value of the cable when migration or upgrade to parallel optic infrastructures occur.

Summary:

Efficiency may be achieved by following the guidelines listed. Cables, patch panels, and cabinets will sustain a longer life cycle, resulting in improved management, lower costs, and the production of a solidly constructed, robust infrastructure.

One additional consideration is the integration of RFID technology on cables, patch panels, cabinets, and servers. RFID integration has shown to be beneficial in automation, connection management, documentation, MACs (moves, adds, changes), and provides readily available product attributes. RFID may also assist in simplifying and automating the information input processes.  RFID adds tremendous value to an organization with the ability to manage assets, assist in information retrieval, improve operational efficiencies, improve reaction to new business requirements, eliminate manual spread sheets, improve asset tracking, and achieve real time accurate information availability.

Remember that product standards are only a starting point.  A common sense approach to business needs is the best standard to follow.