Specifier's Notebook: To Gigabit and Beyond ...
Two special system engineers analyze the current state of facility communication network needs and cabling.
Facility communication functions are quickly converging into large, single networks utilizing common protocols such as Internet Protocol (IP). Leading this trend are voice, data and video applications, but building-management systems-which previously operated over proprietary network backbones-are also integrating circuit types to support IP.
The convergence of these technologies will substantially increase network traffic, which necessitates more bandwidth, superior network administration strategies, enhanced security features and dependable system operation.
To meet the challenges posed by this network convergence, better electronics and cabling are necessary. Gigabit Ethernet network architecture is a good example of the technologies that will satisfy this developing need. Gigabit Ethernet is the latest Ethernet standard for local-area network circuit types, operating at 1,000 Mbps, or ten times faster than Fast Ethernet .
Category-5E UTP cable was standardized by the Electronic Industries Association/Telecommunications Industry Association to support Gigabit Ethernet to the desktop, yet it still offers backward compatibility for existing applications. Soon to be standardized, Category-6 cable will offer the same characteristics, as well as growing space for bandwidths up to 250 MHz. Gigabit Ethernet can also realistically be utilized for backbone distribution where tremendous amounts of information must be transmitted via single- and multi-mode fiber-optic cabling.
While there are major advantages to converging functions onto one network, it is impractical to design an infrastructure using only the 'bleeding edge' cabling technologies. The latest trends may be incompatible with one another, unreliable and expensive. For example, while an 'all fiber' installation can definitely serve all facility needs, the cost will generally be prohibitive.
Instead, a much better design approach for now is to create a stable, robust cabling infrastructure that meets current technology demands while still allowing for transition to newer technologies. This can be accomplished by choosing a diversified cable plant that could include the following:
High pair-count Category-3 cable. This wiring presents an affordable and dependable way to provide the services associated with telephone service, conventional analog/digital PBX and high speed Internet connections such as T1, ISDN and DSL.
Category 5E or 6. This more advanced option can support the above applications, as well as Ethernet (10 Mbps), Fast Ethernet (100 Mbps) and Gigabit Ethernet (1,000 Mbps).
Fiber. This medium must be added to the backbone to support data applications due to length limitations of copper media.
This type of diverse cable plant can 'bulletproof' systems by supporting current technology as well as anticipated future technologies.
In addition, despite growing network traffic and data-transfer rates, the most fundamental step in network design still should be to develop a strong physical support structure. This is because a user's technology requirements are likely to change much more than architectural elements such as communications rooms and distribution pathways. And although cabling is considered part of the infrastructure, it is more likely to get replaced than raceway, thus making raceway more important in the initial installation.
The support structure must promote physical growth and the implementation of new technology, all without unduly impacting the facility's architecture and occupants. Furthermore, when new technology is implemented, networks are rarely taken offline to pull out old cable and install new. Thus it is extremely important to anticipate the future installation of new cabling in conjunction with the initial cabling plant. Every facility should plan for a minimum of 20% physical growth.
Finally, an increase of network traffic must be planned into any communications infrastructure. Designing a 'bulletproof' cable infrastructure that supports the main data stream is vital, but it needs to be done without sacrificing the bandwidth requirements anticipated by future applications and network convergence.
Telecom Infrastructure Keys:
Future technology requirements
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