Ch07 e

Notas del editor

• #5: A standards-based implementation will help to make sure that both current and future technologies can be supported. The TIA/EIA standards addressed at the beginning of this module provide a blueprint to make sure that the project will deliver performance and reliability over the long term Category 5e, Category 6, and fiber-optic solutions should be considered where feasible to ensure that future needs will be met. The number of circuits installed should meet these future requirements as well. It should be possible to plan a physical layer installation that works for ten or more years.
• #6: Installing, maintaining, and supporting separate infrastructures for voice, data, and video is both costly and inefficient. A good end-to-end modular cabling solution that can handle all applications will reduce installation costs and future costs
• #7: The demarc is where outside service provider cables interface with the local system. Backbone cabling is the “main line” of the system. Horizontal cabling distributes services to work areas. The telecommunications rooms are where connections take place to distribute services from backbone cabling to horizontal cabling.
• #8: Telecommunications Industry Association (TIA) and Electronic Industries Alliance (EIA) are trade associations that jointly develop and publish a series of standards covering structured voice and data wiring for LANs Both TIA and EIA are accredited by the American National Standards Institute to develop voluntary industry standards for a wide variety of telecommunications products. This means that many standards are often labeled ANSI/TIA/EIA. The various committees and subcommittees of TIA/EIA develop standards for fiber-optics, user premises equipment, network equipment, wireless communications, and satellite communications.
• #9: Scalability or room for growth is important throughout the entire cable system. 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 gives protection against pairs that may fail during installation, and it also provides for expansion.  To accommodate the changing needs of users in offices, put separate drops to different walls. Employees typically will arrange offices to meet their personal preferences or work flow patterns. Few consider whether the new office configuration is accessible to nearby outlets. Offices can also be changed from single user to multi-user 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.
• #10: To ensure that the labels do not rub off or get cut off (the end) later, mark the cable three times After pulling the cable along the selected route, bring it into the room Use the labels on each spool as a reference, then mark each cable with the appropriate room number and letter. Do not cut the cables unless they have a label
• #11: To ensure that the labels do not rub off or get cut off (the end) later, mark the cable three times After pulling the cable along the selected route, bring it into the room Use the labels on each spool as a reference, then mark each cable with the appropriate room number and letter. Do not cut the cables unless they have a label
• #12: The problem of abandoned cable can be addressed in several ways. One solution is to remove cabling carefully, lifting it from wire ladders and trays rather than pulling it along in the tray. Another is to avoid abandoning cable, but to maintain the labeling and connectivity for at least some kind of application. A final solution may be to recognize the meaning of “accessible” cabling. NEC2002 in several places states that abandoned cable shall not be permitted to remain. In NEC2002 800.52(B) however, the code seems to make room to allow parts of copper cable that is installed but not accessible to be left in place
• #13: 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 recommended. 
• #14: 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 recommended. 
• #15: 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 recommended. 
• #16: There are other terms for some of these subsystems. Telecommunication rooms may also be called main distribution facilities (MDF). The demarcation point is also called the minimum point of entry (MPOE). 
• #17: The equipment room is a similar room that may exist in larger networks or in companies that specialize in telecommunications
• #18: When designing a network, some designers will include both a telecommunications room and an equipment room depending on the amount of equipment and the needs of the customer. A TR should be easily accessible, but it is a vulnerable point in the network and should be well secured.
• #19: This distance must be reduced because wires cannot usually be strung across the floor, but rather 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, once back down) must be subtracted from the proposed work area radius. In addition, ANSI/TIA/EIA-568-B specifies that there can be 5 meters (16.4 ft) of patch cord to interconnect equipment patch panels, and 5 meters of cable from the cable termination point on the wall to the telephone or computer. This must also be deducted from the maximum segment length. Finally, the routes that the cables actually take may not be straight to the destination.
• #20: This distance must be reduced because wires cannot usually be strung across the floor, but rather 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, once back down) must be subtracted from the proposed work area radius. In addition, ANSI/TIA/EIA-568-B specifies that there can be 5 meters (16.4 ft) of patch cord to interconnect equipment patch panels, and 5 meters of cable from the cable termination point on the wall to the telephone or computer. This must also be deducted from the maximum segment length. Finally, the routes that the cables actually take may not be straight to the destination.
• #21: The cables used in the work area can take a lot of abuse. This cable is a good place to start when troubleshooting a connection to a piece of equipment when other equipment around is not having problems. Although the cables are generally made using stranded conductors to help minimize the chance of breaking, many things can happen to it like heavy equipment being set on top of the cable, which can damage the conductors and cause a loss of connectivity. It is always best to replace these cables with factory-made, stranded-conductor patch cables, and route them properly to avoid future damage.
• #22: Telecommunications Grounding Busbars must be made of predrilled copper and be at least 50mm (2 in) wide by 6mm (.25 in) thick, by as long as is required to connect to the bonding wires it serves and to allow for future growth. It must be separated from the wall it is mounted to by insulated standoffs. Each TGB should be located close to the backing board of a telecommunications closet so as to minimize the length of the grounding conductors that attach to it. The TMGB shall be of predrilled copper, and have minimum dimensions of 100mm (4 in) wide and 6mm (.25 in) thick. It shall be as long as is required to support its role as the central grounding point for telecommunications grounding in a building. There is generally only one TMGB, and it should be situated near the main building electrical ground so as to minimize the length of the wire that connects the two. The TMGB must be separated from the wall on which it is mounted by standoff insulators
• #23: Telecommunications Grounding Busbars must be made of predrilled copper and be at least 50mm (2 in) wide by 6mm (.25 in) thick, by as long as is required to connect to the bonding wires it serves and to allow for future growth. It must be separated from the wall it is mounted to by insulated standoffs. Each TGB should be located close to the backing board of a telecommunications closet so as to minimize the length of the grounding conductors that attach to it. The TMGB shall be of predrilled copper, and have minimum dimensions of 100mm (4 in) wide and 6mm (.25 in) thick. It shall be as long as is required to support its role as the central grounding point for telecommunications grounding in a building. There is generally only one TMGB, and it should be situated near the main building electrical ground so as to minimize the length of the wire that connects the two. The TMGB must be separated from the wall on which it is mounted by standoff insulators
• #24: Special cable management systems called innerducts are used exclusively for fiber-optic cables. They are plastic tubing that protect fiber-optic cabling which are then tied to ladder racks Wire minders are used vertically and horizontally on telecommunications racks to distribute cable in a neat and orderly fashion
• #25: Special cable management systems called innerducts are used exclusively for fiber-optic cables. They are plastic tubing that protect fiber-optic cabling which are then tied to ladder racks Wire minders are used vertically and horizontally on telecommunications racks to distribute cable in a neat and orderly fashion
• #26: Special cable management systems called innerducts are used exclusively for fiber-optic cables. They are plastic tubing that protect fiber-optic cabling which are then tied to ladder racks Wire minders are used vertically and horizontally on telecommunications racks to distribute cable in a neat and orderly fashion
• #27: Special cable management systems called innerducts are used exclusively for fiber-optic cables. They are plastic tubing that protect fiber-optic cabling which are then tied to ladder racks Wire minders are used vertically and horizontally on telecommunications racks to distribute cable in a neat and orderly fashion
• #28: If active electronic equipment is also planned for the rack, plans must be made to power this equipment. Many designers put transient-suppressing power strips in the racks, and then run individual power cords down the rack rail to the surge suppressor. Powered equipment generates heat, which must be dispersed. Care must be taken not to block fans or cooling fans. Scalability is also a consideration in an equipment layout, as future growth should be accommodated. Space should be left on a rack for future patch panels, or floor space left for future rack installations in an initial layout
• #29:           Orange - Demarcation point (central office terminations).           Green - Network connections (network and auxiliary equipment).           Purple - Common equipment, private branch exchange (PBX), local area networks (LANs), and multiplexers (switching and data equipment).           White - First-level backbone (MC to an HC or to an IC).           Gray - Second-level backbone (IC to an HC).           Blue - Horizontal cable (horizontal connections to telecommunications outlets).           Brown - Inter-building backbone (campus cable terminations). Brown takes precedence over white or gray for inter-building runs.           Yellow - Miscellaneous (auxiliary, alarms, security) . Red - Reserved for future use (also, key telephone systems).
• #30: In the cross connect fields located in these rooms, cross-connect cables are used to connect the incoming and outgoing cables. Incoming cables are terminated in a field while outgoing cables are terminated in another. The cross-connect wires connect these cables together to provide services. The reasons this method is used are to comply with cable length restrictions and provide easy moves, adds, and changes (MACs )
• #31: One example of using patching over cross-connecting is a telephone in an office where people are moved around often. It is much easier to simply patch the work area outlet circuit to a different outside circuit than it would be to remove terminated wires from connected hardware and re-terminate them to another circuit. Patch cords are also used to connect networking equipment to the cross-connects in a TR
• #32: One example of using patching over cross-connecting is a telephone in an office where people are moved around often. It is much easier to simply patch the work area outlet circuit to a different outside circuit than it would be to remove terminated wires from connected hardware and re-terminate them to another circuit. Patch cords are also used to connect networking equipment to the cross-connects in a TR
• #33: This configuration allows the transmit pins of one device to send signals to the receive pairs of another. If a straight-through cable were used in this situation, the devices would not communicate because the pairs would connect to the same pins on both devices. Crossover cables are used to connect two like devices. Although many pieces of equipment can be set to accept either crossover or straight-through connections, there are some legacy devices in use that still need to be connected using the proper cable type.
• #34: All ICs or HCs are connected to the MC in a star topology. Backbone, or vertical cabling is used to connect those ICs and HCs located on other floors. Where the entire network is confined to a single multi-story building, the MC is usually located on one of the middle floors of the building, even though the demarc might be located on the first floor or in the basement
• #35: ANSI/TIA/EIA-568-B standards specify that ICs should be connected to the MC by using backbone cabling called vertical cabling. When the backbone cable lengths are longer than the Category 5e UTP cable supports, fiber-optic cabling is normally used. Any time the ICs are in separate buildings or on other floors, fiber-optic cabling should be considered.
• #37: Horizontal cabling includes the networking media that is used in the area that extends from the wiring closet to a workstation. Horizontal cabling includes the networking medium that runs along a horizontal pathway to the telecommunications outlet or connector in the work area and the patch cords or jumpers in the HC. According to ANSI/TIA/EIA-568-B.1, the horizontal cable length from the HC to the work area cannot exceed 90 m (295.3 ft). From there, the maximum cable length from the outlet to the workstation is 5m (16.4 ft). In the HC, the maximum length of the cable is 5m (16.4 ft). This is true for all types of Category 5e UTP recognized networking media.
• #38: The MC, IC, and HC are hierarchical in nature. When more than one TR is required, the extended star topology is used. Because more complex equipment is located at the most central point in an extended star topology, sometimes it is referred to as a hierarchical star topology. In the extended star topology, there are two ways in which a HC can be connected to the MC. In the first, each HC can be connected directly to the main distribution facility. In this case, the HC is where the horizontal cabling connects to a patch panel in the TR whose backbone cabling then connects to the switch in the MC. Therefore, this cross-connect is the HC. Alternatively, HCs can be connected to the MC through an IC. When an IC is used, ANSI/TIA/EIA-568-B.1 specifies that only one IC can be used between the HC and the MC
• #39: The MC, IC, and HC are hierarchical in nature. When more than one TR is required, the extended star topology is used. Because more complex equipment is located at the most central point in an extended star topology, sometimes it is referred to as a hierarchical star topology. In the extended star topology, there are two ways in which a HC can be connected to the MC. In the first, each HC can be connected directly to the main distribution facility. In this case, the HC is where the horizontal cabling connects to a patch panel in the TR whose backbone cabling then connects to the switch in the MC. Therefore, this cross-connect is the HC. Alternatively, HCs can be connected to the MC through an IC. When an IC is used, ANSI/TIA/EIA-568-B.1 specifies that only one IC can be used between the HC and the MC
• #40: The MC, IC, and HC are hierarchical in nature. When more than one TR is required, the extended star topology is used. Because more complex equipment is located at the most central point in an extended star topology, sometimes it is referred to as a hierarchical star topology. In the extended star topology, there are two ways in which a HC can be connected to the MC. In the first, each HC can be connected directly to the main distribution facility. In this case, the HC is where the horizontal cabling connects to a patch panel in the TR whose backbone cabling then connects to the switch in the MC. Therefore, this cross-connect is the HC. Alternatively, HCs can be connected to the MC through an IC. When an IC is used, ANSI/TIA/EIA-568-B.1 specifies that only one IC can be used between the HC and the MC
• #41: Backbone, or vertical, cabling consists of the backbone cables, intermediate and main cross-connects, mechanical terminations, and patch cords or jumpers used for backbone-to-backbone cross-connection
• #42: When using MUTOAs, the TIA/EIA-568-B.1 standard specifies the following:           At least one MUTOA is needed for each furniture cluster.           Maximum 12 work areas can be used for each MUTOA.           Patch cords at work areas shall be labeled on both ends with unique identifiers.           Maximum patch cord length is 22 m (72.2 ft).
• #43: In the consolidation point a work area outlet is present near the user. This means users can plug in and remove appliances with ease. The connecting function takes place in the consolidation panel, which often is located in a box in the floor or ceiling. This leads to the question of how it is that the consolidation point is not considered an additional cross-connect, which would violate the standard. The answer may lay in the fact that the horizontal cable leading to the consolidation point terminates in a patch panel or punch block, and the wires from the work areas usually connect to this termination rather than on separate blocks or patch panels. This eliminates patch cords, making the consolidation point an interconnect rather than a cross-connect.
• #44: In the consolidation point a work area outlet is present near the user. This means users can plug in and remove appliances with ease. The connecting function takes place in the consolidation panel, which often is located in a box in the floor or ceiling. This leads to the question of how it is that the consolidation point is not considered an additional cross-connect, which would violate the standard. The answer may lay in the fact that the horizontal cable leading to the consolidation point terminates in a patch panel or punch block, and the wires from the work areas usually connect to this termination rather than on separate blocks or patch panels. This eliminates patch cords, making the consolidation point an interconnect rather than a cross-connect.