Chapter 14: Network Components Flashcards
Analog vs digital signals
analog signals represent data as continuously changing wave values; digital signals encode data in discrete voltage values
Reliability of analog vs digital signals
digital signals more reliable than analog signals over a long distance and provides a clear-cut and efficient signaling method because the voltage is either on (1) or not on (0), compared to interpreting the waves of an analog signal
Synchronous communications
require a timing component but ensure reliability and higher speeds
Asynchronous communications
require no timing component and are simpler to implement
baseband technology
uses the entire communication channel for its transmission
broadband technology
divides the communication channel into individual and independent subchannels so different types of data can be transmitted simultaneously
Coaxial cable
copper core surrounded by a shielding layer and grounding wire, which make it resistant to electromagnetic interference (EMI), provides higher bandwidth, and supports use of longer cable lengths
EMI
electromagnetic interference
Twisted-pair cable
twisting of the wires, types of insulation used, quality of conductive material, and the shielding of the wire determine the rate at which data can be transmitted
Fiber-optic cabling
carries data as light waves, is expensive, can transmit data at high speeds, is difficult to tap into, and is resistant to EMI and RFI; ideal for security protection
Fiber-optic cabling uses glasses and so …
has higher transmission speeds which allow signals to travel over longer distances
depending on the materials used, network cables may be susceptible to ….
noise, attenuation, and crosstalk
line noise
random fluctuations in electrical-magnetic impulses carried along a physical medium
attenuation
the loss of signal strength as it travels
crosstalk
phenomenon which occurs when electrical signals of one wire spill over to the signals of another wire
bandwidth
the amount of information that can be transmitted over a link within a second
data throughput
actual amount of data can actually be carried over a real link
repeater
provides the simplest type of connectivity because it only repeats electrical signals between cable segments, which enables it to extend a network
bridge
LAN device used to connect LAN segments (or VLAN segments) and extends the range of a LAN
transparent bridge
starts to learn about the network’s environment as soon as it is powered on and continues to learn as the network changes by examining frames and making entries in its forwarding tables
STP
Spanning Tree Protocol
Spanning Tree Protocol
ensure forwarded frames do not circle networks forever, provides redundant paths in case a bridge goes down, assigns unique identifiers to each bridge, assigns priority values to these bridges, and calculates path costs
SPB
Shortest Path Bridging
Shortest Path Bridging protocol
defined in IEEE 802.1aq; more efficient and scalable than STP; used in newer bridges
Switches
multiport bridges which typically have additional management features
Routers are in layer ….
Layer 3 or network layer
Routers are
devices used to connect similar or different networks
Routers link …
two or more network segments, where each segment functions as independent networks
router works at the … layer, works with … addresses, has more network knowledge than X, Y, Z
network layer, works with IP addresses, and has more network knowledge than bridges, switches, or repeaters
gateway
general term for software running on a device which connects two different environments and often acts as a translator for them or restricts their interactions
PBX
Private Branch Exchange
Private Branch Exchange
private telephone switch located on an organization’s property and performs some of the same switching tasks which take place at the telephone company’s central office
Proxy server
intermediary between the clients which want access to certain services and the servers which provide those services
NAC
network access control
Network Access Control
any set of policies and controls which restrict access to their networks
endpoint
any computing device which communicates through a network and whose principal function is not to mediate communications for other devices on the network
CDN
content distribution network
content distribution network
consists of multiple servers distributed across a large region, each of which provides content optimized for users closest to it
Regular, high-volume traffic, error checking, high-speed, complex and costly implementation
synchronous signaling
data transfers happen at lower volumes at unpredictable intervals
asynchronous communications
Cheaper than fiber and allows high bandwidths but resistant to electromagnetic interference (EMI)
coaxial cable
cable tray with large number of cables running in parallel and close proximity
crosstalk! electrical signals spill over to the signals of another wire in close proximity unless shielded cables are used
loss of signal strength as it travels
attenuation; regardless of which type of cabling used, it is inevitable given a long enough distance which is why repeaters were invented
bandwidth vs throughput
amount of data that can theoretically be transmitted over a link within a second vs actual amount of data carried over a real link
Layer 3 protocols
OSPF (Open Shortest Path First), BGP (Border Gateway Protocol), IS-IS (Intermediate System-to-Intermediate System)
IEEE 802.1X protocol specifically addresses issues in …..
network access control; allows devices to connect in a very limited manner (only to the network authenticator) until the device and/or user can be authenticated
Multiprotocol Label Switching system
MPLS functionality is built into networking devices to help them move packets between endpoints more efficiently
CDN advantages
reduced latency, tailored content to users around the world, DDoS protection bc of the very distributed nature
