Cable design is a critical element of a quality data center. With the volume of data cables required for interconnectivity between servers, storage, and core network switching, data center cabling architects must plan in advance when considering cabling architectures to support their facilities. Six operational characteristics which are critical to consider:
- Access layer flexibility
- Capacity and service scalability
- High availability and fabric stability
- Consistency
- Easy operations and management
- A simple, deterministic topology
In addition to the critical operational characteristics above, it is important to consider six cabling characteristics which will impact the cabling approach:
- Scalability
- Flexibility and management
- Availability
- Cost
- Media type
- Life expectancy
Once the operational and cabling characteristics have been reviewed and evaluated, there are several design approaches and choices to make. Data cabling designers consider:
Top-of-Rack versus End-of-Row Aggregation
Network design within the data center significantly impacts the final cabling design. For most build-outs, network architects will consider either a Top-of-Rack or End-of-Row aggregation design for core network switching. A discussion between the network architect and cabling architect will help to drive the best approach for a particular data center build-out.
Field Terminated vs. Pre-Terminated Cabling
Cables can be either field-terminated or pre-terminated and each approach has advantages and disadvantages to consider. Data center cabling architects need to consider both when determining the design approach as well as the aptitude and skills of cabling technicians. It is not always feasible to field terminate cables and pre-terminated cabling should be considered.
Inside-of-Cabinet vs. Outside-of-Cabinet Termination
After deciding upon aggregation switch location and cabling termination, cable designers need to consider the termination approach at the cabinet or rack itself. The two choices include Inside-of-Cabinet and Outside-of-Cabinet terminations. As with field termination and pre-termination, one approach is not better than the other. Rather, the decision comes down to various factors such as expected cabinet churn rate, possible re-organization of cabinets down the road, and typical data center IT solution refresh requirements.
Copper vs. Fiber Media
The two choices for data center cabling are copper and fiber media. Cable designers need to understand the specific network design structure, expected distances within the enterprise environment, and current and future bandwidth requirements to determine the best approach to media.
In summary, a number of factors influence the best suited cabling architecture and design for a data center build. There is not one specific approach that is better than all others. The requirements of the data center IT and facility supporting infrastructure, along with future requirements, budget, modularity, etc., drive the best approach for a particular situation. A Registered Communications Distribution Designer or RCDD should work with the IT and data center operations personnel to determine the proper approach for your data center.
For more information on the topic of data center cabling design, download PTS’ new White Paper – Cable Architecture Design for Next Generation Data Centers (registration required) or email us.
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