Bits across the Wire Flashcards
: What layer is
‘moving ones and zeroes from one end of the link to the next’ the main focus of?
Main focus of physical layer
What layer consists of: devices and means of transmitting bits across networks.
Physical
The smallest representation of data a computer can understand. A one or a zero.
Bit
groups of ones and zeros sent across networks at the lowest level. No matter what you are doing online, you are sending these.
frames and packets of data
a way of varying the voltage of a charge moving across a cable.
Modulation:
Cabling constantly carries
an electrical charge.
line coding. Allows devices on either end of the link to let network devices know that a certain charge is a zero or a one.
modulation for computer networks
Speed of modern networking:
10 billion bits/s
The most common type of cabling
twisted pair cable
the most common type of cabling for connecting computing devices. Features pairs of copper wires twisted together.
Twisted pair cable
. Most common. act as a single conduit for information.
copper pairs
8 wires, consisting of four twisted pairs, inside a single jacket.
Standard Cat6 cable, Cat cable.
What depends on the transmission technology being used. Modern ones allow for duplex comm.
Pairs in use
the concept that information can flow in both directions across the cable.
duplex communication
Simplex communication
Unidirectional process of transmitting information.
What is possible when wiring Reserves one or two pairs for communication in one direction, and reserves the other one or two pairs for communicating in the other direction.
duplex communication
devices on either side of a networking link can communicate with each other at the exact same time.
Full duplex:
what can a connection degrade to?
connection can degrade to half duplex.
while the devices can communicate in either direction, only one device can communicate at a time.
half duplex
coaxial cable is an example of
twisted pair cable
can also supply telephone and television services:
ethernet over twisted pair technologies, cable.
What is delivered by this: coaxial cable or fiber optic cable from an internet service provider, ISP. Connection is fed to a gateway modem located inside the building or home, often provided by ISP. Modem then passes the connection through a twisted pair ethernet cable to a router or a single computer. Router uses twisted pair ethernet cables to distribute wired network connections internally to business or home.
How an internet connection to a building or home is normally delivered
two copper wires. One for transmitting and the other for receiving data, laid parallel to each other.
original telephone and early data cables:
old wires affected by:
EMI, Radio frequency interference, cross talk.
