Not long ago, it was not uncommon for a student to have to trudge across campus in order to use one of the school's computer terminals. In today's competitive education market, that simply is unacceptable. Students and researchers expect direct access from their personal computers to the institution's mainframe and a myriad of computing applications.
Unfortunately, most school telecommunications infrastructures do not fully support current and projected needs, which is forcing institutions to upgrade. Properly planned, an upgraded telecommunications infrastructure will support state-of-the-art data, voice and video applications today and for the next several decades.
Essential elements Infrastructure design is the key to a powerful, adaptable telecommunications system. One of the most difficult tasks in creating a telecommunications network is designing a system that can be adapted to future changes. Many current infrastructure designs fail to address voice, video and data. Therefore, whenever a school changes equipment, the infrastructure must be expanded, upgraded or replaced.
To be flexible and reconfigurable, design an infrastructure that supports the different technologies. Then, as technology changes, the system can be upgraded by changing end components. To achieve this, create a common, fiber-optic-based physical network with sufficient fiber to support all three telecommunications elements.
An effective way to design this infrastructure is to break the campus into areas, usually by function. Fiber-distribution points can be located in equipment rooms throughout the campus, with fiber-optic cables being installed between distribution points, or nodes.
If the distribution points are designed with pass-through, patch and cross-connect capability, technicians or a contractor can reconfigure the network to accommodate changes in network topology, to bypass cable cuts or accommodate new construction--all without interrupting service. Depending on what construction activities are taking place, the telecommunications cable duct bank may have to be severed. Creating a ring/subring infrastructure allows technicians to reroute the flow of information from any of those strategically located equipment rooms.
Laying the groundwork There are two types of fiber-optic cable: single-mode and multi-mode. Each has distinct characteristics, and, in order to meet an institution's current and future needs, both should be installed. Use of a hybrid cable, which consists of both multi-mode and single-mode fibers in a single jacket, minimizes cable pulls and conduit space, reducing the time and cost of installation.
A well-designed fiber-optic infrastructure should provide sufficient fiber-optic capacity for several decades. The reason is that as technology increases, the need for fiber decreases. In fact, the limiting factor on the amount of information that can be carried along a fiber-optic cable is not the cable--it is the transmit and receive equipment at each end. As laser technology continues to progress, more information can be transmitted on a single strand of fiber.
The conduit system should be designed to minimize construction costs, maintain low-pulling friction to protect fibers during installation, and support telecommunication needs well into the future. Selecting the most efficient route (one that minimizes both the length of conduit required and the number of street and utility crossings), selecting conduit to enable future expansion, and providing pull points at strategic locations are important in achieving these goals.
Conduits typically are installed about 3 feet below grade and encased in concrete, with a metallic warning tape placed about 1 foot below grade. If precast hand holes or manholes are placed at convenient pulling distances and building entrances, then future construction required to connect new facilities can be accomplished at the nearest hand hole. Filling each conduit with innerduct liners reduces pulling friction and subdivides conduits for future use. Spare conduits, with empty innerduct liners, should be provided for future services.
In addition to inadequate infrastructure, many schools are struggling with outdated telephone systems. Institutions are requiring many telephone features, such as abbreviated dialing, voice mail, automated attendants, message centers for event announcements and ticket sales, and call accounting. These features require a single or integrated telephone network.
Build for speed and volume The design of a data network must incorporate speed and volume. Determine how many users need to connect, how many need to exchange information, and the projected volume of use. The traditional copper-based network often functions below today's standards for speed, and troubleshooting is difficult, which results in high system maintenance and low reliability.
The most challenging aspect is implementing a local-area network (LAN) that will function effectively into the future. Select the best technology the institution can afford that meets current and projected needs, keeping in mind that there always will be a new technology just around the corner. One of the current state-of-the-art technologies is a LAN backbone based on asynchronous transfer mode (ATM) technology, which offers these benefits:
*Fiber-optic equipment, which increases system reliability. *A topology capable of operation using redundant fiber paths and capable of supporting exponentially growing data requirements. *A network-management station, which monitors the network and provides warnings and alarms to alert network administrators to imminent problems with the system. A fiber-based ATM data network will support more users than a copper-based network at greater speed and performance.
East Carolina University (ECU), Greenville, N.C., recently completed an integrated telecommunications system for its 17,500 students. ECU's administration and Division of Computing and Information Services worked closely with the engineers to plan and design a fiber-optic infrastructure that would be flexible, capable of being reconfigured, and sized to support current and future applications.
The infrastructure design breaks the campus down into six areas by function. Fiber distribution points are strategically located in equipment rooms and fiber-optic cables are installed between nodes, forming a combination ring/subring and star topology. The infrastructure, which serves 70 buildings on the main campus and health-science campus, has 144 strands of fiber on the main ring and 72 strands on the subrings. The distribution points have pass-through, patch- and cross-connect capability. The system uses a hybrid cable consisting of both multi-mode and single-mode fibers in a single jacket.
The installation required a total of 35,000 feet of trench, which was reduced by using common routes for the rings and subrings, and by minimizing the number of obstacles and street crossings.
In total, the ECU installation required 69,000 feet of single-mode and 75,000 feet of multi-mode fiber. In addition, the installation required 90,000 feet of 4-inch conduit and 130 fiber-optic distribution panels.
Once installation of below-ground conduit was completed, the crews were able to begin pulling cable and work in various equipment rooms without interrupting the daily campus activities. The university decided to provide its own local telephone service, including voice mail, abbreviated dialing, caller identification, and the capability of developing a campus emergency-dispatch system that would identify the origin of the call. The main campus is divided into four individual SONET nodes, which are connected in a bi-directional line switched-ring configuration.
ECU elected to build comprehensive broadcast and interactive video systems, controlled and managed from a video-distribution center housed with the SONET and telephone main switching center. This permits import and export of live video to and from multiple campus locations using a single link to the public switched network.
The 80-channel broadcast system is distributed over the fiber-optic network to faculty, staff and students. Five channels are interfaced directly to the local cable-television company, allowing ECU to send local programming to the community and receive and re-broadcast public programming on campus. The interactive video system provides distributed switching over the fiber-optic infrastructure to specific staff and faculty locations to provide distance learning and videoconferencing capability.
Both systems are capable of interfacing with the public switched network, providing access to North Carolina Department of Education's Information Highway. This design will allow ECU the flexibility to use a myriad of interactive video systems, or combine various manufacturers' equipment, and to customize its interactive video sessions. The total project cost, including design, construction, hardware and software, was $13 million, of which $3.4 million was for the infrastructure.