Cabling
/ LAN Terms
10BaseT
The Ethernet
specification that allowed for 10 Mbps transmission over unshielded twisted
pair (UTP) cables. Unlike the 10Base2 and 10Base5 topologies, cabling is done
as a physical star, with all WAO cabling brought back to a hub location. While
logically operating as a bus, the advantages of a physical star topology are
many – a single defective station couldn’t bring the entire network down.
Station changes were much easier to implement, and most hubs had diagnostics
that could partition a problematic station as to not effect the rest of the
network. This topology has been the most popular in the history of LAN design
and installation.
110
Connector (AT&T)
A connector
type developed by AT&T which allowed for flexible cable terminations and
maximum cable density. Organized on a plastic field into 25 Pair rows, the
connecting clip (‘C’ Clip) is available in 3,4, and 5 pair designations
for different uses. The ‘C’ clip connector provided an internal bridge to
be used between the station cable termination and upstream sources (hubs,
voice switches etc) without any other intermediate connections. The connector
has been widely adopted in instances where small connector size and high
density are desirable (patch panels and voice fields are quite common).
66 Block (Siemons
66M-150)
General purpose
connecting blocks used for a variety of applications. The blocks consist of
columns of pins, with 50 pins in a column. These blocks mount on backboards
using brackets. The conductors are seated into the pins, which are calibrated
to strip the conductor insulation without breaking the conductor, providing a
point of electrical contact.
Asymmetric Cryptography
In this Cryptography a Key Pair - Private and Public Key is used. Private Key is kept secret and the Public Key is Widely distributed.
ACR
(Attenuation to Crosstalk Ratio)
Similar to a
ratio comparing signal strength and noise, this is a measurement that is
critical for high-speed data transmission. This is often a numeric value (in
decibels) which express the difference between NEXT (Near End Crosstalk) and
attenuation at a particular frequency.
Attenuation
A measure of
signal loss over distance. This is essentially the reduction of the signal
strength over distance. It is important with data transmission for many
reasons, most having to do with the signal strength and signal to noise ratios
at the receiving end.
ATM
(Asynchronous Transfer Mode)
A fast,
switching cell topology that can achieve transmission speeds of 150 Mbps to 1
Gbps. This Protocol has been selected by the ITU (International
Telecommunications Union) as the transport protocol for broadband ISDN in the
future. Because it uses a fixed cell length (for data packets), ATM is
extremely efficient, and bandwidth use is relatively flexible. It is capable
of handing a combination of voice, data and video traffic.
ACPI
(Advanced C onfiguration and Power Interface) is a
power management specification that allows the operating system to control the
amount of power distributed to the computer's devices. Devices not in
use can be turned off, reducing unnecessary power expenditure. ACPI
defines a new interface to the system board, and enables the OnNow design
initiative for instantly available PCs.
AGP
(Accelerated G raphics Port) is a PCI-based interface
that was designed specifically for demands of 3D graphics applications.
The 32-bit AGP channel directly links the graphics controller to the main
memory. While the channel runs at only 66 MHz, it supports data
transmission during both the rising and falling ends of the clock cycle,
yielding an effective speed of 133 MHz. [ top]
AIMM
(AGP I n-line Memory Module) - 4 MB Display Cache
card that plugs into the AGP port to gain additional performance.
AMR
(Audio Modem Riser) is Intel's specification on
motherboard design. Motherboard with this type of architecture allows
for designs w/o analog I/O functions. However, these functions can be
added by the codec chip on a riser card, which plugs into the motherboard
perpendicularly, resulting in better audio quality.
Array
is two or more hard disk drives grouped together to appear as a single device
to the host computer. [top
]
AT
was the original form factor of IBM's PC.
ATAPI
(AT A ttachment Packet Interface), also known as IDE or
ATA, is a drive implementation that includes the disk controller on the device
itself. It allows CD-ROMs and tape drives to be configured as master or
slave devices, just like hard drives. [top]
ATX
form factor was designed to replace the AT form factor. It improves on
the AT design by rotating the board ninety degrees, so that the IDE connectors
are closer to the drive bays, and the CPU is closer to the power supply and
cooling fan. The keyboard, mouse, serial, USB, and parallel ports are
built in.
Backbone
A High-Speed
link connecting hubs, concentrators, servers or other devices which require
more bandwidth than an individual workstation.
Backbone
Cabling
Cables used to
link Telecommunications Closets (TC) with the Main Cross Connect (MC) or
Equipment Room (ER). In Premises Distribution System terminology, this would
be similar to linking IDF’s with the MDF. Due to the increased data
transmission rates of network backbones, cables supporting increased bandwidth
or transmission speeds are sometimes specified as ‘backbone cables’.
Optical Fiber cable, while rarely used to the WAO, is often used as the
backbone cable of choice.
A range of
consecutive frequencies. This is term is used primarily to describe the
capacity of a cable, source or connector. As bandwidth increases, the amount
of potential data transmission also increases.
A small piece
of metal used to bridge several termination positions on a 66-M150 style
termination block.
Broadband
A cable capable
of carrying several signals simultaneously on different channels.
Bus segment
A portion of a
network based on the Bus Topology. This term was used most often with station
counts and repeating requirements of 10Base2 based Ethernet networks.
Bus Topology
A network
topology based on all stations attaching to a single transmission channel.
This was popularized with 10Base2 and 10Base5 networks. Several disadvantages
exist for Bus based networks – all stations on the network hear all network
traffic, and problems with one station or link can bring down the entire bus.
Bandwidth
refers to carrying capacity. The greater the bandwidth, the more data
the bus, phone line, or other electrical path, can carry. Greater
bandwidth, then, also results in greater speed. [ top]
A BBS
(Bulletin Board System) is a computer system with a
number of modems hooked up to it which acts as a center for users to post
messages and access information.
The BIOS
(Basic Input/Output System) program resides in the
ROM chip, and provides the basic instructions for controlling your computer's
hardware. Both the operating system and application software use BIOS
routines to ensure compatibility. [top]
A buffer
is a portion of RAM that is used to temporarily store data, usually from an
application, though it is also used when printing, and in most keyboard
drivers. The CPU can manipulate data in a buffer before copying it, all
at once, to a disk drive. While this improves system performance --
reading to or writing from a disk drive a single time is much faster than
doing so repeatedly -- there is the possibility of losing your data should the
system crash. Information stored in a buffer is temporarily stored, not
permanently saved.
A bus
is a data pathway. The term is used especially to refer to the
connection between the processor and system memory, and between the processor
and PCI or ISA local buses. [top]
Bus
Masptering
allows peripheral devices and IDEs to access the system memory without going
through the CPU (similar to DMA channels).
- Certificate
- A Data Record that contains the
information as defined in the X.509 Format.
- Certificate Authority (CA)
(CA)
- Issuer of the Digital Certificate.
Also validates the Identity of the End-Entity that posseses the Digital
Certificate.
- Certificate Signing Request
(CSR) (CSR)
- Certificate Signing Request (CSR) is
what you send to a Certifiate Authority (CA) to get enrolled. A CSR
contains the Public Key of the End-Entity that is a requesting the
Digital Certificate.
- Common Name (CN) (CN)
- Common Name is the name of the
End-Entity e.g. Saqib Ali. If the End-Entity is a WebServer the CN is
the Fully Qualified Domain Name (FQDN) of the WebServer
Categories
A rating system
developed to outline specifications for cabling, connectors and termination
practices as they apply to Unshielded Twisted Pair cabling and data
transmission. These standards have been developed to insure interoperability
and acceptable levels of performance from differing components.
Category 3
The EIA/TIA
grading system which denotes UTP cabling or connecting hardware with
transmission characteristics up to 16 MHz. This grade of cable was primarily
used in 10BaseT and Token Ring (4 Mbps) installations.
Category 5
The EIA/TIA
grading system which denotes UTP cabling or connecting hardware with
transmission characteristics up to 100 MHz. This grade of cable is the most
common UTP cable installed today for use with data transmission. Correctly
installed, it provides bandwidth sufficient for Fast Ethernet (100BaseT), 16
Mbps Token Ring, and TP-PMD.
Category 5e
An evolving
standard which had not been ratified as of September 1998, this standard is
expected to denote cabling or connecting hardware which will support Gigabit
Ethernet (also sometimes called 1000BaseT). As would be expected, the
transmission characteristics for Cat 5e will be much more stringent than those
for Cat 5.
A
Cache
is a temporary, fast storage area that holds data from a slower storage device
for quick access as needed by an application. Access time is fast using
a cache, because the needed information is stored in the SRAM instead of in
the slower DRAM. Note that the cache is also much smaller than your
regular memory: a typical cache size is 512KB, while you may have as much as
2GB of regular memory. [ top]
Cache
size refers
to the physical size of the cache onboard. This should not be confused
with the cacheable area, which is the total amount of memory that can be
scanned by the system in search of data to put into the cache. A typical
setup would be a cache size of 512KB, and a cacheable area of 512MB. In
this case, up to 512MB of the main memory onboard is capable of being cached.
However, only 512KB of this memory will be in the cache at any given moment.
Any main memory above 512MB could never be cached.
Closed
and open jumpers
Jumpers and jumper pins are active when they are On or Closed, and inactive
when they are Off or Open. [top]
CMOS
(Complementary M etal-Oxide Semiconductors) are
chips that hold the basic start-up information for the BIOS.
CNR
(C ommunication & Network Riser)
Codec
(Color-decoder) is a filter that manipulates data in some form,
usually by compressing or decompressing the data stream. [top]
The COM
port is
another name for the serial port, which is so-called because it transmits the
eight bits of a byte of data along one wire, and receives data on another
single wire (that is, the data is transmitted in serial form, one bit after
another). Parallel ports transmit the bits of a byte on eight different
wires at the same time (that is, in parallel form, eight bits at the same
time).
Distance
Limitation
Expressed as a
maximum, it is the tested maximum length for link. For Ethernet over UTP
cable, the distance limitation would be 90 meters for the link (workstation
cabling) and 100 meters for the Channel (Workstation cabling plus applicable
patch cables). While it is possible that a link will function over the
distance limitation, most vendors will not support links that exceed the
distance limitation.
DC
(Display Cache)
DIMM
(Dual In-line Memory Modules) are a faster and
more capacious form of RAM than SIMMs, and do not need to be installed in
pairs. [top]
DIMM
banks are
sometimes called DIMM sockets, because the physical slot and the logical unit
are the same. That is, one DIMM module fits into one DIMM socket, which
is capable of acting as a memory bank.
DMA Direct Memory Access channels are similar to IRQs.
DMA channels allow hardware devices (like sound cards or keyboards) to access
the main memory without involving the CPU. This frees up CPU resources
for other tasks. As with IRQs, it is vital that you do not double up
devices on a single line. Plug and Play devices will take care of this
for you. [top]
In Doze
mode , only
the CPU's speed is slowed.
DRAM
(Dynamic
RAM) is a widely available, very affordable form of RAM that has the
unfortunate tendency to lose data if it is not recharged regularly (every few
milliseconds). This refresh requirement makes DRAM slower by a factor of
three to ten compares to non-recharged RAM such as SRAM. [top]
Dulpexing
- RAID means
mirroring across two RAID cards.
EIA
(Electronics Industries Association)
An industry
group consisting of users, manufacturers, suppliers and installers of
electronic equipment. The group assists in the formation of standards and
specifications, which insure equipment with similar or interrelated functions,
are compatible with each other.
EIA/TIA 568A
This standard
applied to the Commercial Building Standard for Telecommunications Wiring
Standards. Specifications are outlined for minimum specifications for office
cabling, acceptable cable types, topologies, distance limitations, pinouts,
detailed cable and component specifications, electrical attributes and so
forth.
EIA/TIA 569
This standard
applied to the Commercial Building Standard for Telecommunications Pathways
and Spaces. Specifications are outlined for the size, placement, pathways,
environmental conditions and design parameters for Entrance Facilities (EF),
Telecommunications Closets (TC), Equipment Rooms (ER) and Work Area Outlets (WAO).
EIA/TIA 570A
This standard
applies to Residential and Light Commercial Telecommunications Wiring and
Cabling Standards. As the design parameters and needs of the Residential and
Light Commercial buildings were distinctly different than those for Commercial
Buildings, a separate set of guidelines was written.
EIA/TIA 606
This standard
applied to the Administration Standard for the Telecommunications
Infrastructure of Commercial Buildings. Specifications are outlined for the
size, placement, pathways, environmental conditions and design parameters for
Entrance Facilities (EF), Telecommunications Closets (TC), Equipment Rooms
(ER) and Work Area Outlets (WAO).
EIA/TIA 607
This standard
applied to the Commercial Building Standard for Grounding and Bonding.
Grounding is the providing of a conduction path from equipment or a circuit to
the earth. This is important to limit any shock dangers and provide a minimum
amount of electrical potential variances. Bonding is the use of conductors to
bridge several grounding conductors to each other.
ECC
(Error-Correcting Code) functions to test the accuracy of
data transmission, both in and out of memory. [top]
EDO
DRAM (Extended
Data Output DRAM) a faster type of DRAM in that it can
start working on the next block of memory at the same time it sends previous
one to CPU.
EEPROM
(Electrically Erasable Programmable ROM) also
called Flash BIOS, is a ROM chip that can, unlike normal ROM, be updated.
This allows you to keep up with changes in the BIOS programs without having to
buy a new chip. TYAN's BIOS updates
. [top]
ESCD
(E xtended System Configuration Data) is a format
for storing information about Plug and Play devices in the system BIOS.
This information helps properly configure the system each time it boots.
FDDI
One of the
first 100 Mbps network types was FDDI. Distributed over Optical Fiber cable,
FDDI could support up to 1000 stations over a total distance of 100
Kilometers. Comprised of two concentric rings, a token is passed in opposite
directions on each ring. This allows for fault tolerance – if the ring were
to be broken, it would be possible to route data around the break. This
redundant routing feature makes FDDI extremely reliable.
FEP
(Fluorinated Ethylene-Propylene)
A synthetic
polymer often used in communications cable insulation.
FEXT (Far
End Crosstalk)
A new
measurement, this is the effect of Crosstalk measured at the opposite end from
where it is being disturbed. At the higher bandwidths required by current
network equipment, the measurement of and elimination of signal noise becomes
of paramount importance.
Fiber Optic
Also called
‘Optical Fiber Cable’, this would be a fine glass strand (measured in
microns) that is used by Light-emitting diodes. The electrical signal is
converted to pulses of light, transmitted through the optical fiber cable and
re-assembled back to electrical signals at the remote end. Due to its optical
nature, fiber has extremely lenient distance limitations, and is rarely
effected by sources of outside interference that would be detrimental to
copper based connections.
Floor Cell
A cell system
implemented when buildings are built, it is usually comprised of metallic
raceways in the slab, or concrete that facilitate distribution of cabling to
WAO through the floor. Generally speaking, a floor cell system is comprised of
two parts, the floor cells to allow placement of WAOs, and the trench, which
the cells intercept at right angles. The trench is a larger pathway to
facilitate routing of cables to equipment rooms or telecommunications closets.
Floor Trench
The second
component (with Floor Cells) in an under--carpet cabling distribution system.
This is installed when buildings are built and is usually comprised of
metallic raceways in the slab, or concrete that facilitate distribution of
cabling to WAO through the floor. Generally speaking, a floor cell system is
comprised of two parts, the floor cells to allow placement of WAOs, and the
trench that the cells intercept at right angles. The trench is a larger
pathway to facilitate routing of cables to equipment rooms or
telecommunications closets.
Fault
Tolerance
refers to the ability of a system to continue to perform its functions even
when one or more hard disk drives have failed. [top]
Firmware
is low level software that controls the system hardware.
Form
factor is an
industry term for the size, shape, power supply type, and external connector
type of the PCB (personal computer board) or motherboard. The standard
form factors are the AT and ATX, although TYAN also makes some Baby-AT boards.
[ top]
Hub
Equipment used
to link multiple network devices with each other.
A
Global timer
is an onboard hardware timer, such as the Real Time Clock.
Handshaking
is a form of encryption. One system, typically the server, sends an
encryption scheme to another agent, typically a client. Thus, the
client's data is protected during transmittal to the server. [ top]
HCT
(Hardware Compatibility Test) is a suite of tests from
WHQL that verifies hardware and device driver operations under a specific
operating environment.
HDD
stands for H ard Disk Drive. [top]
Hot
Spare drive
will automatically be used to replace the failed member of a redundant disk
array.
Hot
Swap refers
to the ability to remove a failed member of a redundant disk array and replace
it with a good drive without bringing down the server or interrupting
transactions that involve other devices. [ top]
H-SYNC
controls the horizontal properties of the monitor.
IBM
Type 1
A thick,
shielded cable invented by IBM for use with token ring networks. A total of
two pairs of 22 AWG conductors, the pairs are shielded from each other, and
both pairs are shielded together. While expensive and difficult to terminate,
this cable provided suitable bandwidth for 4 Mbps and 16 Mbps Token Ring, and
was extensively used in the 1980’s.
IBM Type 2
An IBM Type 1
cable with an additional UTP four pair bonded in the outer jacket. Sometimes
used where voice and data termination points would allow.
Intermediate
Distribution Frame (IDF)
This term has
been replaced by Telecommunications Closet (TC) by ANSI/TIA/EIA. It is a
component of a hierarchical cabling system. The IDF, or TC would be the point
at which local station cables would terminate, as well as a backbone cable
that would provide connectivity to the MDF or ER.
IC
(Integrated Circuit) is the formal name for the computer chip. [top]
IDE
(Integrated D evice/Drive Electronics) is a
simple, self-contained hard drive interface. It can handle drives up to
8.4GB in size. Almost all IDEs sold now are in fact Enhanced IDEs (EIDEs).
IDE
INT (IDE
Interrupt) is a hardware interrupt signal that goes to the IDE. [top]
I/O
(Input / O utput) is the connection between your computer and
another piece of hardware (mouse, keyboard, etc.).
IRQ
(Interrupt Request) is an electronic request that runs
from a hardware device to the CPU. The interrupt controller assigns
priorities to incoming requests and delivers them to the CPU. It is
important that there is only one device hooked up to each IRQ line; doubling
up devices on IRQ lines can lock up your system. Happily, Plug and Play
operating systems take care of these details for you. [top]
ISA
(Industry S tandard Architecture) is a slower 8- or
16-bit BUS (data pathway).
LAN
(Local Area Network)
A systematic
approach to data communications in which common resources are shared by
multiple users. A local area network is geographically limited in area, and
does not exclusively utilize physical media owned by others (i.e. a Local
Telephone Carrier etc).
Mbps
(Megabits per second)
One million
bits per second.
MC (Main
Cross Connect)
Interchangeable
with Equipment Room (ER).
MPOE
(Minimum Point of Entry)
A term used to
describe the first termination point of underground cables bringing dial tone
and outside services to a building. This can be the same as the Demarcation
Point.
Multi-mode
Optical Fiber
Relatively
inexpensive compared to Single Mode Optical Fiber, Multi-Mode fiber has a much
larger central core than Single Mode, and the glass is tuned to reflect
signals towards the center of the core. This allows light to be refracted
through the cable. The electronics used in Multi-Mode fiber are much less
precise, as the available source-to-fiber aperture (opening) is somewhat
large. Light Emitting Diodes (LED’s) are often used with Multimode Fiber.
NAT
Network Address Translation
Pair
A coupling of
two conductors to be used together. They are often twisted together or color
coded in a manner to allow their easy identification.
Patch Cable
Used with Patch
Panels or WAO’s, these are to connect equipment with the physical wiring
structure, then to equipment on the remote end. A hub would utilize patch
cables to a patch panel, which provides a termination point for station
cabling. At the remote end of the station cabling, a patch cable would be used
from the WAO to the device or computer.
Patch Panel
The physical
termination points where cables are converted to connectors for using in
patching services. Patch panels are signified by several parameters, such as
Jack type, number of ports, types of terminations, pair capacity, and mounting
options. The most common panel in use today is a RJ45 panel, where station
cables are wired the panel, which uses circuit cards or jumper wiring to
provide a corresponding RJ45 port. This port, in combination with patch
cables, provides an easy, manageable and flexible way to provide different
services to the WAO.
Proprietary
1 : one that possesses,
owns, or holds exclusive right to something; specifically :
2 : something that is used, produced, or marketed under
exclusive legal right of the inventor or maker; specifically : a
drug (as a patent medicine) that is protected by secrecy, patent, or copyright
against free competition as to name, product, composition, or process of
manufacture
3 : a business secretly owned by and run as a cover for an
intelligence organization
PVC (CMR)
Do to its fire
resistance characteristics, these cables are not suitable for use in air
return (air plenum) ceilings. The CMR designation denotes a CM branded PVC
jackets that are also suitable for use between floors. All PVC jacketed CMR
cables will carry the letters CMR on the cable jacket.
Rack
Available in a
variety of widths (19", 23" and 25" are the most common, with
19" being the standard) and heights (7" is the standard), equipment
racks are aluminum, predrilled frames in which network equipment, patch
panels, and wire management are mounted. Due to their standard drilling and
sizing, all ‘rack mountable’ equipment and patching hardware can generally
be mounted in an equipment rack.
Reflected
Ceiling Plan
A architectural
print which details all ceiling level construction, which may include HVAC
registers and returns, light fixtures and fire sprinkler heads.
Resistance
A force that
tends to slow or oppose current flow through a medium. All cables inherently
exhibit resistance to current flow.
RFI (Request
for Information)
A document
submitted to the project manager, architect or general contractor that asks
for specific information or clarification that the contractor or consultant
feel is overlooked or unclear.
RJ21X
A 66-M150
terminating block that has a hinged cover attached. These are often used for
incoming dial tone, as the cover provides a location for circuit labeling.
RJ45
An industry
term describing an eight conductor, keyed connector. This has become the
Standard connector for many networks, including Ethernet (10BaseT) and Fast
Ethernet (100BaseT). This term may describe either the male (patch cable) end
or the female (Outlet location) end. [ top]
Single
Mode
A designation
for Optical Fiber cable that has an extremely small central core. This has
advantages and disadvantages - as the path of light through the fiber
straightens, data timing becomes less variable. This can result in increased
bandwidth and higher data transmission rates. The disadvantages include the
electronics required for Single Mode fiber are much more precise than those
used for Multi-Mode fiber, and are also much more expensive. Lasers are
generally used with Single Mode fiber due to its narrow aperture. [ top]
TC
(Telecommunications Closet)
Predesignated
rooms, closets or areas to be used for the termination, connection and
equipment for horizontal, vertical or backbone cabling installations.
TIA
(Telecommunications Industries Association)
A subgroup of
the Electronics Industry Association (EIA), the TIA was formed in 1988 to
assist with formation of standards and specifications to govern components and
protocols in use for data distribution systems and telecommunication
equipment. Standards were first introduced in 1991, and have continued to
evolve since then. [ top]
Token Ring
A network
protocol using a token method of access appropriation. Each station shares
network usage equally, and access is governed by a ‘token’, which is
shifted from station to station. The ‘token’ would contain the addresses
of the sending and receiving stations, and the data to be transmitted. If the
station with the ‘token’ has no network requests, it simply sends the
‘token’ on to the next station. [ top]
TSB – 67
The Technical
Service Bulletin (TSB) which was amended to the EIA/TIA 568A specification for
appointment and clarification of approved testing procedures and minimum
values. This standard provided for four cable parameters to be tested: Length,
Wire Map (Pin Out), Attenuation and Near End Cross Talk (NEXT). Cables or
infrastructure which is to be considered ‘Category 5’ or ‘Category 5
Compliant’ must adhere to these specifications. [
top]
UTP
(Unshielded Twisted Pair)
Two conductors,
generally 24 AWG, wrapped around each other as to form a pair. Multiple pair
groups are combined in a single outer insulation (of PVC or Plenum
composition) to form a Paired cable. The pairing and twisting of the pairs can
determine their suitability for data transmission, impervious to outside
influences, and reliable distance limitations.
Vertical
Cabling
Cabling which
connects several floors of a building. Generally refers to Backbone or Riser
cabling. [ top]
WAN
(Wide Area Network)
A network which
is not bound by a particular geographic area. This may consist of satellite
offices in several states or countries. Many methods may be used to connect
these offices, but these methods would not rely on physical infrastructure
owned by the end user. [ top]
WAO (Work
Area Outlet)
A vague and
somewhat nebulous term used to describe a location where connections would be
required. Used interchangeably with ‘drop’, ‘outlet’ and
‘station’. This would describe any situation whereas connectivity, either
voice / data or video a combination would be required. [
top]
Wire
Management
Components of a
Structured Cabling System (SCS) which provide for tractable and manageable
patch and connector cable routing and support. [ top]
Wire Map
