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White Paper

Fiber-Optic Cabling Connectivity Guide for 40-Gbps
Bidirectional and Parallel Optical Transceivers

What You Will Learn

As data centers consolidate into more complex systems, they take advantage of new speed increases and

technologies. The speed changes from 1- to 10-Gbps infrastructure were easy to understand. With speeds in the

data center now increasing from 10 Gbps to 40 Gbps and eventually to 100 Gbps, different optical technologies

and cabling infrastructure are required. This document introduces the cable requirements for 40-Gbps

infrastructure and fundamental cabling principles supporting Cisco Nexus® 9000 Series Switches. Although

alternative cabling options are mentioned (Twinax and active optical assemblies), the main focus of the document

is cabling for pluggable optical Enhanced Quad Small Form-Factor Pluggable (QSFP+) modules.

The new Cisco Nexus 9000 Series provides high 1-, 10-, 40-, and (future) 100-Gbps Ethernet densities with

outstanding performance and a comprehensive feature set. The Cisco Nexus 9000 Series provides a versatile

platform that can be deployed in multiple scenarios - direct-attach 1-, 10-, and 40-Gbps access and collapsed

aggregation and access deployments, leaf-and-spine architecture, and compact aggregation solutions.

Structured (Semi-permanent Links) or Unstructured System

When designing a networking system, it is important to plan the cabling system in advance. The goal is to address

current network requirements as well as accommodate future growth. A structured cabling system provides a

flexible cabling plan to address the commonly performed tasks of moving, adding, and changing the infrastructure

as the network grows. A good analogy for a structured cabling system is the electrical wiring in your home. When

connecting appliances and devices, you require only a 5-foot connection to the closest electrical outlet. However,

without an electrical outlet, all appliances would have to connect directly to the breaker or panel, requiring a cable

of 200 feet or more. This approach would be inefficient and would become unmanageable as you add multiple

appliances and devices throughout the home. The structured wiring is those permanent wires in the walls and

ceilings to electrical outlets throughout your home. The same concept applies to data centers with the deployment

of robust cabling links between two patch panels (similar to the outlets in the wiring example). Structured cabling

becomes a necessity as the infrastructure grows and as constant moves and changes reinforce the need for a

reliable network that is also easy to troubleshoot.