Chapter 4: Structured Cabling and Networking Elements

surge protector

A device that directs excess voltage away from equipment plugged into it and redirects it to a ground, thereby protecting the equipment from harm.

Electronic Industries Alliance (EIA)

A former trade organization composed of representatives from electronics manufacturing firms across the United States that sets standards for electronic equipment and lobbies from legislation favorable to the growth of the computer and electronics industries. EIA (Electronic Components, Assemblies, Equipment & Supplies Association), but the standards brand name, EIA, will continue to be used.

network diagrams

A graphical representation of a network's devices and connections.

electric circuit

A medium for the transfer of electrical power over a closed loop.

brownout

A momentary decrease in voltage, also known as a sag. An overtaxed electrical system may cause brownouts, recognizable as a dimming of the lights.

brownout

A momentary decrease in voltage; also known as a sag. An overtaxed electrical system can cause brownouts, which you might recognize in your home as a dimming of the lights. Such voltage decreases can cause computers or applications to fail and potentially corrupt data.

surge

A momentary increase in voltage caused by distant lighting strikes, solar flares, or electrical problems.

CSMA/CD (Carrier Sense Multiple Access with Collision Detection)

A network access method specified for use by IEEE 802.3 (Ethernet) networks. In CSMA/CA, before a node begins to send data, it checks the medium. If it detects no transmission activity, it waits a brief, random amount of time, and then sends its transmission. If the node does dect activity, it waits a brief period of time before checking the channel again. SCMA/CA does not eliminate, but minimizes, the potential for collisions.

punch down tool

A pointed tool used to insert twisted-pair wire into receptors in a punch-down block to complete a circuit.

half-duplex

Signal may travel in both directions over a medium but in only one direction at a time.

simplex

Signal may travel in only one direction, and is sometimes called one-way, or unidirectional, communicaiton.

full-duplex or duplex

Signals are free to travel in both directions over a medium simultaneously.

FCS ( frame check sequence)

Trailer 4 bytes

intermediate distribution frame (IDF)

a junction point between the MDF and end-user equipment. The TIA/EIA standard specifies at least one IDF per floor, although large organization may have several data closets per floor to better manage the data feed from the main data facilities.

cross-talk

a phenomeno cause by transmission interference between wires.

offline UPS

a standby UPS doesn't provide continuous power

half-racks

an equipment rack that is about half the height of the standard rack. Standard racks measure 42U, but half-racks are typically 18U-22U tall.

Cable trays

are usually metal trays built into equipment racks, office desks, or even along the ceiling to help collect cables into a single track.

CRC (cyclic redundancy check)

ensure that the data at the destination exactly matches the data issued from the source

noise

fluctuation in voltage levels caused by other devices on the network or EMI. Some noise is unavoidable on an electrical circuit, but excessive noise can cause a power supply to malfunction, immediately corrupting program or data files and gradually damaging motherboards and other computer circuits.

plenum cabling

if you run cable in the plenum, the area above the ceiling tile or below the subflooring, make sure the cable sheath is plenum-rated, and consult with local electric installation codes to be certain you are installing it correctly. A plenum rated cables is coated with a flame-resistant jacket that produces less smoke than regular cable coated with PVC (polyvinyl chloride) In the event of a fire, smoke produced by plenum cabling is less toxic than that produced by PVC cabling.

avoid EMI

install cable at least 3 feet away from fluorescent lights or other sources of EMI.

Thunderbolt

is Apple's proprietary competitor to the USB port and can be used to connect several types of external peripheral devices Mac computers.

iSCSI (Internet SCSI)

is a Transport Layer protocol that runs on top of TCP to allow fast transmissions over LAN, WAN, and the Internet.

Fibre Channel (FC)

is a Transport Layer protocol used on fiber-optic media instead of TCP or UDP.

UPS (uninterruptible power supply)

is a battery-operated power source directly attached to one or more devices and to a power supply, such as a wall outlet, that prevents undesired fluctuations of the wall outlet's AC power from harming the device or interrupting its servives.

SAN (storage area network)

is a distinct network of storage devices that communicate directly with each other and with other networks.

Fiber-optic cable

is a form of cable that contains one or several glass or plastic fibers in its core and comes in two types: single-mode fiber (SMF) or multimode fiber (MMF).

wiring schematic

is a graphical representation of a network;s wired infrastructure.

patch cable

is a relatively short (usually between 3 and 25 feet) length of cabling with connectors at both ends.

Telecommunications Industry Association (TIA)

is a single cabling standard formulated

network attached storage (NAS)

is a specialized storage device or group of storage devices that provides centralized fault-tolerant data sharing.

shielded twisted pair (STP)

is a type of copper-based cable containing twisted-wire pairs that are not only individually insulated, but also surrounded by a shielding made of a metallic substance such as foil.

unshielded twisted pair (UTP)

is a type of copper-based cable that consists of one or more insulated twisted-wire pairs encased in a plastic sheath.

electromagnetic interference (EMI)

is a type of interference that may be caused by motors, power lines, televisions, copiers, fluorescent lights, or other sources of electrical activity. This reduce the possibility of noise (interference) that can affect your network's signals.

hub

is an inefficient and outdated networking device that has been replaced by switches.

vertical cross connect

is one of the component of the backbone which runs between a building's floors. Ex (connect MDF and IDF or two IDF within building.) (On modern networks, backbones are usually composed of fiber-optic or UTP cable.)

volt-ampere (VA)

is the product of the voltage and current (measured in amps) of the electricity on a line. 1.4 volt-amps = 1 watt (w)

bend radius

is the radius of the maximum arc into which you can loop a cable without impairing data transmission. A twisted-pair cable's bend radius is equal to or greater than four times the diameter of the cable.

collision domain

is thee portion of a network in which collisions could occur.

slack in cable runs

measure first, and always leave some slack in cable runs. Stringing cable too tightly risks connectivity and data transmission problems.

media access control (MAC)

method used by the nodes for arbitration on the network.

entrance facility

the location where an incoming network service (whether phone, the Internet, or long-distance service enters a building and connects with the building's backbone cabling.

rack units (RU or U)

the measured with the industry standard being 42U tall about 6 feet.

ethtool

utility allows you to view and change NIC settings.

3 hour

$5000

documentation

-cable documentation -lable every jack or port -use color cables different -update documentation

574 VA UPS

20 minute

cost

5 to 10 minutes cost $100 and $300

1100 VA UPS

90 minute

work area

an area that encompasses all patch cables and horizontal wiring necessary to connect the NICs in workstations, printers, and other network devices to the data closet.

four-post rack

an equipment rack consisting of four vertical side posts to which equipment is attached via brackets incorporated in the posts.

two-post rack

an equipment rack consisting of two vertical side posts to which equipment is attached via brackets incorporated in the posts.

cinch cables loosely

avoid cinching cables so tightly with cable ties that you squeeze their outer covering, a practices that leads to difficult-to-diagnose data errors.

protect cables

avoid laying cable across the floor where it might sustain damage from rolling chairs or foot traffic. If you must take this tack, cover the cable with a cable protector or cord cover.

alternating current (AC)

continually switches direction on the circuit.

rectifier

converts AC to DC. All computers require the constant flow of electricity that DC power provides. The power supply in a laptop or desktop computer contains a rectifier to convert AC to DC.

inverter

converts DC to AC. A generator might contain an inverter. The better inverters will also condition the power, which helps protect sensitive electronic equipment from power fluctuations.

speed and duplex mismatch

speed and duplex that's not supported by the neighboring device and cause a failed transmissions.

company standards and stock

standard cable use by organization and maintain lists of approved cabling vendors.

loopback plug or loopback adapter

test the NIC or cable with a loopback.

backbone wiring

the cables or wireless links that provide interconnection between entrance facilities and MDFs, and between MDFs and IDFs.

main distribution frame (MDF) or main cross connect

the first point of interconnection between an organization's LAN or WAN and a service provider's facility. (The first door Internet enters into the building.)

period of time to keep a device running

the longer you anticipate needing a UPS to power your device, the more powerful your UPS must be.

Medium sized server with a monitor and external tape drive

use 402 W ,and requiring a UPS capable of providing at least 562 VA power.

Desktop computer

use a 200 W power supply, and require a UPS capable of at least 280 VA to keep the CPU running.

termination

when terminating twisted-pair cabling, don't leave more than 1 inch of exposed (stripped) cable before a twisted-pair termination.

horizontal wiring

wiring that connects workstations to the closest data closet. The maximum allowable distance for horizontal wiring is 100m. This span includes 90 m to connect a data jack on the wall to the data closet plus a maximum of 10 m to connect a workstation to the data jack on the wall. (((90 m to data closet) and (10 m to the node or workstation)))

configuration management

The collection, storage, and assessment of information related to the versions of software installed on every network device and every device's hardware configuration.

blackout

a complete power loss. A blackout could cause significant damage network. For example, if a server loses power while files are open and processes are running, its NOS might be damaged so extensively that the server cannot restart and the NOS must be reinstalled from scratch.

KVM (Keyboard video mouse) switch

a device that connects the equipment in a rack to a single console to provide a central control portal for all devices on the rack.

line conditioning

a type of filtering to guard against line noise or special noise filters that remove line noise.

110 block

a type of punch-down block designed to terminate Cat 5 or better twisted-pair wires and typically used to handle data connections rather than telephone connections. The numeral 110 refers to the model number of the earliest blocks. (more suitable for data connections than the older 66 block)))))

Nmap

A scanning tool designed to assess large networks quickly and provide comprehensive, customized information about a network and its hosts. Nmap, which runs on virtually any modern operating system, is avaailable for download at no cost at nmap.org

66 block

A type of punch-down block designed to terminate telephone connection. The numeral 66 refers to the model number of the earliest blocks.

Power converters

change the form of electrical energy in some way.

Transformer

changes the voltage of AC, such as when the power over the main line from the electric company is transformed before being delivered to your house.

black-out

complete loss of power

direct current (DC)

flows at a steady rate in only one direction

Voltage regulator

maintains a constant voltage level for either AC or DC power.

grounding

pay attention to grounding requirements and follow them religiously.

Rack systems

provided mounting hardware for network equipment to optimize the use of square footage in equipment rooms and ensure adequate spacing, access, and ventilation for these devices. 19 inch frame = 10 inch wide.

collision

1.) In Ethernet networks, the interference of one node;s data transmission with the data transmission of another node sharing the same segment. 2.) In the context of hashing, a problem that occures when the input of two different data sets result in the same hash value.

airflow

In a chassis, the path along which air from a cool air source is conducted, past equipment to cool it, and then out of the rack. Typically, air moves from front to back. Clutter in the rack should be minimized to prevent airflow blockages.

server rails

Slides mounted directly on a rack to make equipment access easier for technicians to service the equipment without completely removing as they arrive.

Preamble

The field in an Ethernet frame that signals to the receiving node that data is incoming and indicates when the data flow is about to begin.

network mapping

The process of discovering and identifying the devices on a network.

power redundancy

The provision of a backup power source, such as a generator.

device driver or driver

The software that enables an attached device, such as a NIC or mouse, to communicate with the computer's operating system.

standby UPS or standby power supply (SPS)

provides continuous voltage to a device by switching virtually instantaneously to the battery when it detects a loss of power from the wall outlet.

fault tolerance

refers to techniques that allow data storage or other operations to continue in the event of a failure or fault of one of its components.

verify continuity

use a cable tester to verify that each segment of cabling you install transmits data reliably. This practice help track down errors in multiple, long stretches of cable.

cable trays

use cable management devices such as cable trays, braided sleeving, and furniture grommets, but don't overfill them.

patch panels

use patch panels to organize and connect lines. patch panel is a rack-mounted panel of data receptors. -help keep lines organized as they run from walls to racks to network devices, and they make it easy to switch out patch cables of variable lengths when devices are moved or changed.

online UPS

use the AC power from the wall outlet to continuously charge its battery, while providing power to a network device through its battery.