Exercising Due Diligence

By Author: John Tang
Total Articles: 512
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Having examined their requirements and satisfying themselves that category 6 cabling is the best solution to their network requirements, office planners should prepare themselves to evaluate the offerings of various vendors' responses to an RFP. This will equip them to sort through various marketing hype and find out if, indeed, the proposed components deliver a network that is up to spec. Here the key word is components. There are several that together make up the office LAN. In addition to the cabling itself, there are connectors, jacks, patch cords and other components that contribute to connectivity.

For example, while some manufacturers claim to have a category 6 product, these claims may be based on channel performance and may not reflect actual connecting hardware performance. Diligence is also required when reviewing how performance claims are phrased. Terminology such as average or 90th percentile should be rejected. The only acceptable low-end parameters are worst pair or worst link indicators. Claims of zero bit error rate cannot be verified by test. Furthermore, testing equipment cannot correct ...
... for bad cable, and no cabling system can correct errors. High-quality cabling can only reduce the incident of errors.

Risk is further reduced when warranties are provided. Manufacturers should warranty category 6 performance and applications support especially because they are selling a product prior to formal standards body acceptance. If they are unwilling to assume this risk in writing, chances are the performance margins of their product do not exceed those of the proposed category 6 standard.

Performance verification by independent third-party testing laboratories showing worst case configurations is an essential ingredient in a response to an RFP. As noted above, these tests should show that both the channel (cable) and individual components pass the proposed category 6 standards. Moreover, vendors must verify that they offer a complete range of category 6 products, that all of them are backward compatible with lower performing categories such as 5 and 5e, and that they will not degrade the performance of these lower categories. An assurance of full technical support by certified installers is non-negotiable.

A Macro Look at Premise Cabling Systems
High-bandwidth cabling systems are no longer confined to large corporate offices. Today companies of any size must provide an infrastructure capable of supporting all employees' voice and data requirements. Since office planners or managers in smaller organizations frequently wear several hats, they should have a basic understanding of a premise (office) cabling system. The following paragraphs serve as a primer.

Starting with the basics, and largely under the control of a building owner or manager and telecommunications service provider is the entrance facility. It is here where service provider cabling enters and interconnects with a building's backbone cabling system via the main cross connect. Somewhat like a building's water supply system, the backbone cabling system (also called riser cable because it rises vertically) is the primary conduit carrying communications traffic between a building's occupants and the outside world. Various standards apply to the design and construction of a riser cabling system. Well-planned buildings will have separate but parallel riser systems for voice, data and video circuits in order to facilitate expansion or modification of services. These systems should not share space with a building's electrical supply system.

Riser cable terminates in one or more telecommunications closets on each floor, and it is here where office planners start getting involved. The telecommunications closets serve as access points to the outside world, and provide connectivity between office occupants. Through horizontal cross connects the closets are transition points between the vertical riser system and horizontal cabling system serving occupants of each floor.

Before the onslaught of high-speed data networks and LANs, cabling offices was a relatively straightforward process with no distance limitations, no pathway constraints and no closet requirements. Telephones, fax and telex machines were hard wired into the network, and that was that. But with the advent of the computer and the proliferation of equipment to be accessed within and from the office, standards were called for. These are embodied in TIA/EIA-568A and 569A. They require installers to meet more stringent installation standards to protect the integrity of the cable system and eliminate the need for constant re-cabling with the addition of each new application.