2. Cabling and Topology Flashcards
network topology
Describes how computers connect to each other in that network. The topologies on the test are star, bus, ring, and mesh.
bus topology
All computers connected to the network via a main line. The cable (bus) was terminated at each end to prevent signal reflections.
ring topology
All computers on the network attached to a ring of cable. A single break would stop the data for everyone.
star topolgy
All computers connect to a central wiring point, providing fault tolerance.
hybrid topologies
Star-bus and star-ring. Only star-bus is used today.
mesh topology
Each computer connects to every other via 2 or more routes. Used in wireless networks.
two forms of copper cabling
coaxial (coax) and twisted pair
coaxial cable
Shields against EMI. Was used widely in early bus networks with BNC connectors.
Mainly used to connect a cable modem to an ISP now.
coax ratings
RG-6 is the predominant coax today.
twisted pair types
Comes either shielded or unshielded and is the most common type of network cable.
UTP is less expensive and more popular.
UTP ratings
Cat 5 Cat 5e Cat 6 Cat 6a are the most common, but Cat 3 Ca7 are also on the test.
UTP connector
RJ-45 (which is really a 8P8C)
2 types of fiber-optic cable
LED - MMF (multimode fiber)
Laser - SMF (single-mode fiber)
modal distortion
A situation that occurs in MMF where signals that are sent at the same time don’t arrive at the same time due to slight variations in the length of their paths.
4 fiber-optic cable parts
The core; the cladding, which covers the fiber and helps to reflect light down the fiber; buffer material to give strength; and the outer insulating jacket.
4 common fiber connectors
ST
SC
LC
MT-RJ
UTP fire ratings
A plenum-rated cable gives off less smoke and fumes than PVC but costs more. Plenum is often required by city ordinance.
A PVC-rated cable offers no significant fire protection.
serial cable
An old, retired cable used for point-to-point connections. The connector was a DB-9 and looked like a male VGA.
RS-232 protocol.
parallel cable
An old, retired cable. The connector was a DB-25.
IEEE-1284 set the standards for parallel communication.
IEEE 802
Committee that defines frames, speeds, distances, and types of cables used in networks. It split into subcommittees like 802.3 and 802.11
8P8C
8 position 8 contact (commonly referred to as RJ-45)
bandwidth
The amount of data that goes through a cable per second.
buffer
Material found within the insulation of a fiber optic cable to give it strength.
BNC connector
An early model of connector used on coax cables.
category (Cat) rating
Measures the bandwidth of a cable.
cladding
The covering over the actual fiber of a fiber-optic cable which reflects light down the line.
core
The glass fiber in a fiber-optic cable.
crosstalk
When a signal transmitted on one circuit interferes with the signal on another. (Increasing the twists per foot in UTP decreases crosstalk).
EMI
electromagnetic interference
F (F-type) connector
Replaced the BNC connector for coax. Screws into place.
fault tolerance
A single fault in the network won’t bring the whole thing down.
fiber-optic cable
Transmits data way further than copper, but is more expensive, less durable, and less flexible.
fully meshed topology
Refers to a wireless network where each computer has a direct connection to every other computer.
hybrid topology
Any form of networking that combines a physical topology (an actual layout) with a signaling topology (how the electrical current travels).
insulating jacket
The outer layer of a fiber-optic cable.
physical topology
The arrangement of devices on a computer network and how they communicate with one another.
MMF
multimode fiber (used for LELDs)
SMF
single-mode fiber (used for LASERs)
network topology
The way that cables and other pieces of hardware connect to one another.
segment
in bus topology:
The new, smaller bus that was put inside a router.
logical topology
Relating to how a signal travels electronically (ie, how the circuit works).
Ohm rating
A measure of resistance in a cable
partially meshed topology
In this topology, at least two machines have redundant connections.
