CCNA 1 and 2 Companion Guide, Revised (Cisco Networking Academy Program) part 92 docx

Appendix A Structured Cabling This appendix covers the following topics: ■ Structured cabling systems, standards, and codes ■ Safety ■ Tools of the trade ■ The installation process ■ The finish phase ■ The cabling business ■ Case study Completing this material and the associated labs in the Cisco Networking Academy Program CCNA 1 and 2 Lab Companion, Third Edition, will provide a broad introduction to all facets of structured cabling installation. Structured Cabling Systems, Standards, and Codes Structured cabling systems refer to telecommunications wiring built in a standardized, approved manner, starting at the demarcation point, working through the various equip- ment rooms, and continuing to the work area. The issue of scalability also is addressed. Items of importance that students should be aware of include these: ■ Rules of structured cabling ■ Subsystems of structured cabling ■ Scalability ■ Demarcation point ■ Telecommunications and equipment rooms appen_a.fm Page 879 Tuesday, May 20, 2003 4:54 PM 880 Appendix A: Structured Cabling ■ Work areas ■ MC, IC, and HC ■ Telecommunications Industry Association (TIA) and Electronic Industries Association (EIA) ■ European Committee for Electrotechnical Standardization (CENELEC) ■ International Organization for Standardization (ISO) ■ U.S. codes ■ Evolution of standards Rules of Structured Cabling for LANs Structured cabling is a systematic approach to cabling. It is a method for creating an organized cabling system that can be easily understood by installers, network adminis- trators, and any other technicians that deal with cables. The following three rules help ensure that the structured cabling design projects are both effective and efficient: ■ Look for a complete connectivity solution—An optimal solution for network connectivity includes all the systems that are designed to connect, route, manage, and identify structured cabling systems. A standards-based implementation will help to make sure that both current and future technologies can be supported. Following standards makes sure that the project will deliver performance and reliability over the long term. ■ Plan for future growth—The number of circuits installed should meet these future requirements as well. Category 5e, Category 6, and fiber-optic solutions should be considered where feasible to ensure that future needs will be met. It should be possible to plan a physical layer installation that works for ten or more years. ■ Maintain freedom of choice in vendors—Even though a closed and proprietary system may be less expensive initially, this could end up being much more costly over the long term. A non-standard system from a single vendor may make it more difficult to to make moves, adds, and changes at a later time. More Information For more information on the rules of structured cabling, visit www.panduitncg.com/NCG_SYSSOL/ncg_syssol_pm/ncg_syssol_pm_markets/Finance/rules.asp. appen_a.fm Page 880 Tuesday, May 20, 2003 4:54 PM Structured Cabling Systems, Standards, and Codes 881 Subsystems of Structured Cabling Seven subsystems are associated with the structured cabling system (see Figure A-1). Each subsystem performs certain functions to provide voice and data services through- out the cable plant. Figure A-1 Subsystems of Structured Cabling Backbone Pathways Equipment Room Horizontal Pathways Entrance Room/Main Terminal Space Interbuilding Backbone Alternate Entrance Antenna Entrance Telecommunications Room Backbone Pathways Demarcation Point Telecommunications Outlet Box Work Area Telecommunications Room Horizontal Pathways appen_a.fm Page 881 Tuesday, May 20, 2003 4:54 PM 882 Appendix A: Structured Cabling ■ The demarcation point (demarc) within the entrance facility (EF) in the equip- ment room ■ The telecommunications room (TR) ■ Backbone cabling, also known as vertical cabling ■ Distribution cabling, also known as horizontal cabling ■ The work area ■ Equipment room (ER) ■ Administration The demarc is where the outside service provider cables connect to the customer’s cables in the facility. Backbone cabling is the feeder cables that are routed from the demarc to the equip- ment rooms and then on to the telecommunications rooms throughout the facility. Horizontal cabling distributes cables from the telecommunication rooms to the work areas. The telecommunications rooms are where connections take place to provide a transition between the backbone cabling and horizontal cabling. These subsystems make structured cabling, by nature, a distributed architecture with management capabilities that are limited to the active equipment (PCs, switches, hubs, etc.). Designing a structured cabling infrastructure that properly routes, protects, iden- tifies and terminates the copper or fiber media is absolutely critical for network perfor- mance and future upgrade. Scalability A LAN that can accommodate future growth in size is referred to as being scalable. It is important to plan ahead when estimating the number of cable runs and cable drops in a work area. It is always easier to ignore extra installed cables than to not have them when they are required. In addition to pulling extra cables in the backbone area for future growth, it is also common practice to pull an extra cable to each workstation or desktop for future use. This protects against pairs that might fail during installation and also provides for expansion. Backbone Scalability To determine how much extra copper cabling to pull, first determine the number of runs that are needed now and then add some extra, about 20 percent. appen_a.fm Page 882 Tuesday, May 20, 2003 4:54 PM Structured Cabling Systems, Standards, and Codes 883 One way to obtain this reserve capability is to use fiber-optic cabling and equipment in the building backbone. Updating the termination equipment (by inserting faster lasers and drivers, for example) can accommodate fiber growth. Work Area Scalability Although it might be obvious that each work area needs one cable for voice and one for data, other devices might need a connection to either the voice system or the data system. Network printers, fax machines, laptops, or another user in the work area all can require their own network cable drops. When the cables are in place, use multiport wall plates over the jacks. Many types of configurations are possible for either walls or partition walls. In addition, use jacks that are color-coded to make it easier to identify types of circuits. Administration stan- dards require that every circuit should be clearly labeled to assist in connections and troubleshooting. A new technology that is becoming popular is Voice over Internet Protocol (VoIP). This technology allows special telephones to use data networks when placing telephone calls. A great advantage to this technology is the capability to avoid costly long-distance charges by using this service over existing network connections. Other devices, such as printers and computers, can be plugged into the IP phone. The IP phone thus becomes a hub or switch for the work area. Even if these types of connections are planned, enough cables should be installed to allow for growth. Especially consider that IP telephony and IP video traffic may share the network cables in the future. To accommodate the changing needs of users in offices, it is recommended to provide at least one spare cable to the work area outlet. Offices might change from single-user to multiuser spaces. In these cases, a work area can become inefficient if only one set of communication cables were pulled. Assume that every work area could accommodate multiple users in the future (see Figure A-2). Demarcation Point The demarcation point (demarc), provides the point at which outdoor cabling inter- faces with the intrabuilding backbone cabling (See Figure A-3). It represents the boundary between the service provider’s responsibility and that of the customer. In many buildings, this is near the point of presence (POP) for other utilities, such as electricity and water. appen_a.fm Page 883 Tuesday, May 20, 2003 4:54 PM 884 Appendix A: Structured Cabling Figure A-2 Allow for Growth Figure A-3 Demarcation Point The service provider is responsible for everything from the demarc to the service provider’s facility. Everything from the demarc into the building is the customer’s responsibility. appen_a.fm Page 884 Tuesday, May 20, 2003 4:54 PM Structured Cabling Systems, Standards, and Codes 885 The local telephone carrier typically is required to terminate cabling within 15m (49.2 ft.) of building penetration and to provide primary voltage protection. This usually is installed and provided by the service provider. The Telecommunications Industry Association (TIA) and Electronic Industries Associ- ation (EIA) develop and publish standards for many industries, including the cabling industry. To ensure that the cabling installation is safe, is installed correctly, and retains performance ratings, these standards always should be followed when performing any voice or data cabling installation or maintenance. TIA/EIA-569-A specifies the standards for the demarc space. The standards for the structure and size of the demarc space are based on the size of the building. In buildings larger than 2000 usable square meters, a locked, dedicated, and enclosed room is rec- ommended. The following are general guidelines when setting up a demarcation point space: ■ Allow 1m 2 of plywood wall mount for each 20m 2 (215.3 ft 2 ) area of floor space. ■ The surfaces where the distribution hardware is mounted must be covered with fire-rated plywood or plywood that is painted with two coats of fire-retardant paint. ■ Either the plywood or the covers for the termination equipment should be col- ored orange to indicate the point of demarcation. Telecommunications and Equipment Rooms After the cable enters the building through the demarc, it travels to the entrance facility (EF), which is usually in the equipment room (ER). The equipment room is the center of the voice and data network. An equipment room is essentially a large telecommuni- cations room that may house the main distribution frame, network servers, routers, switches, the telephone PBX, secondary voltage protection, satellite receivers, modula- tors, high-speed Internet equipment, and so on. The design aspects of the equipment room are specified in the TIA/EIA-569-A standard. In larger facilities, the equipment room may feed one or more telecommunications rooms (TR) which are distributed throughout the building (see Figure A-4). A wiring hub and patch panel in a TR may be mounted to a wall with a hinged wall bracket, a distribution rack (see Figure A-5), or a full equipment cabinet. appen_a.fm Page 885 Tuesday, May 20, 2003 4:54 PM 886 Appendix A: Structured Cabling Figure A-4 Telecommunications Room Figure A-5 Panduit Distribution Rack appen_a.fm Page 886 Tuesday, May 20, 2003 4:54 PM Structured Cabling Systems, Standards, and Codes 887 ■ If the choice is a hinged wall bracket, the bracket must be attached to the plywood panel that covers the underlying wall surface. The purpose of the hinge is to allow the assembly to swing out so that workers and repairmen easily can access the back side of the wall. Care must be taken, however, to allow 48 cm (18.9 in.) for the panel to swing out from the wall. ■ If you are using a distribution rack, it must have a minimum of 1 meter (3 feet) of workspace clearance in the front and rear of the rack. A 55.9-cm (22-in.) floor plate, used to mount the distribution rack, provides stability and determines the minimum distance for its final position. ■ If the patch panel, hub, and other equipment are mounted in a full equipment cabinet, they require at least 76.2 cm (28.6 in.) of clearance in front, for the door to swing open. Typically, such equipment cabinets are 1.8m high × .74m wide × .66m deep (5.9 ft. × 2.4 ft. × 216.5 ft.). Equipment must be placed in equipment racks with care. Considerations include whether the equipment uses electricity, cable routing, cable management, and ease of use. For example, a patch panel would not be placed high on a rack if a significant number of changes were to take place after the systems were installed. Convenience of use is a large consideration when planning the equipment layout. Scalability is also a consideration in an equipment layout because future growth should be accommodated. Space should be left on a rack for future patch panels, or floor space should be left for future rack installations in an initial layout. Proper installation of equipment racks and patch panels in the TR allows easy changes and modifications to the cabling installation in the future. This is important when con- sidering the design and layout of the work areas. Work Areas The area serviced by an individual telecommunications room is called a work area. In most cases, a work area occupies one floor or part of one floor of a building (see Figure A-6). The maximum distance for a cable from the termination point in the TR to the termination at the work area outlet must not exceed 90 meters (295 ft). This 90 meter maximum horizontal cabling distance is referred to as the permanent link. Each work area must have at least two cables, one for data and the other for voice. As previously discussed, accommodations for other services and future expansion must also be considered. appen_a.fm Page 887 Tuesday, May 20, 2003 4:54 PM 888 Appendix A: Structured Cabling Figure A-6 Work Areas This distance must be reduced because cables usually cannot be strung across the floor; they usually ride in wiring-management devices such as trays, baskets, ladders, and raceways. These devices route the paths of the wires above workspaces, often in the plenum areas above suspended ceilings. This means that the height of the ceiling times two (once up to the wiring management device and once back down) must be sub- tracted from the proposed work area radius. In addition, ANSI/TIA/EIA-568-B specifies that there can be 5m (16.4 ft.) of patch cord to interconnect equipment patch panels, and 5m of cable from the cable termina- tion point on the wall to the telephone or computer. This additional maximum of 10 meters of patch cords added to the permanent link is referred to as the horizontal channel. The maximum distance for a channel is 100 meters—the 90 meter maximum permanent link plus 10 meters maximum of patch cords. Finally, the routes that the cables actually take might not be straight to the destination. Wiring-management devices can be costly, and the location of heating, ventilation, and air-conditioning equipment; power transformers; and lighting equipment can dictate paths that add length. This further decreases the radius of the work area. Typically, when everything is taken into account, the actual radius might be closer to 60 to 70m (196.9 to 229.7 ft.) than 100m (328.1 ft.); 50m (164 ft.) commonly is used as a work- area radius for design purposes. appen_a.fm Page 888 Tuesday, May 20, 2003 4:54 PM . closer to 60 to 70m (19 6.9 to 22 9.7 ft.) than 10 0m ( 328 .1 ft.); 50m (16 4 ft.) commonly is used as a work- area radius for design purposes. appen_a.fm Page 888 Tuesday, May 20 , 20 03 4:54 PM . Cisco Networking Academy Program CCNA 1 and 2 Lab Companion, Third Edition, will provide a broad introduction to all facets of structured cabling installation. Structured Cabling Systems, Standards,. May 20 , 20 03 4:54 PM Structured Cabling Systems, Standards, and Codes 885 The local telephone carrier typically is required to terminate cabling within 15 m (49 .2 ft.) of building penetration and