Chapter 6: Telecommunications + Networking Flashcards
Computer Network
A System that connects Computers (Compu’s) + Other devices (i.e. Printers) via communications media so that data + info can be transmitted among them
Consist of Nodes + other thing
Bandwith
Refers to Transmission Capacity of a Network, it’s stated in bits per second
(we use very large bandwith, in mill/billions, if it’s less than using the Internet takes more time, 5G Infrastructure Towers?)
Broadband
Transmission Capacity of a Communication Medium
Local Area network (LAN)
Connects 2 or more devices in a limited geographical region, usually within the same building
i.e. LAN could be in a Classroom (box-like router thing)
Wide Area Network (WAN)
A Network that covers a large geographical area.
WAN’s typically connect multiple LAN’s
i.e. Internet in Uni Campus = WAN, connects diff college building LAN’s?
Router
A Communications processor that routes messages from a LAN to the Internet, across several connected LAN’s, or across a wide area network such as the Internet
Enterprise Network
Organizational interconnected networks consisting of multiple LAN’s + may also include multiple WAN’s
Corporate Backbone Networks
High - speed central networks to which multiple smaller networks (i.e./such as LANs + Smaller WANs) connect
Software - Defined Networks (SDN)
An emerging tech,
With SDN, dec’s controlling how much network traffic flows across network devices are managed centrally by software
The Software dynamically adjusts data flows to meet Bu + Application needs
LAN vs WAN
LAN’s = connected via a switch (which allows connections to multiple devices, manages ports, manage VLAN security settings) and switch connected to Router (which directs data to a network)
That router connected to other routers which connected to WAN, this connects Routers as well as the Remote user to the WAN
Digital Signals
Discrete pulses that either on or off,
Representing a series of bits (0s + 1s, 0 = off, 1 = on???)
This quality allows digital signals to convey info in a binary form that can be interpreted by compu’s
Modem or Modulator-demodulator
Converts digital signals to analog signals (this process called Modulation) + analog signals —>/to digital signals (this process called Demodulation)
The name modem is a contraction of Modulator-Demodulator
Analog vs Digital vs Brain/Neuron Spiking Signal
Neuron spiking signal similar to previous two signals?
Communications Media + Channels:
Communication Channel
A pathway or medium communicating data from 1 location to another
Communications Media
Is the Physical media used to send data (i.e Twisted - pair wire, (wire in desk in classroom) Coaxial Cable, Fiber Optic Cable (expensive_, Satellite, etc)
Then the three cables in i.e section are listed again
Adv vs Disadv of Wireline Communications Channels
Twisted Pair:
Adv:
Inexpensive
Widely Available
Easy to work with
Disadv:
Slow (low bandwidth)
Subject to interference (it Copper wire?)
Easily tapped (Low Security)
Coaxial Cable:
Adv:
High bandwidth per twisted pair
Less susceptible to electromagnetic interferences
Disadv:
Relatively Expensive + Inflexible
Easily Tapped (low to med security)
Somewhat difficult to work with
Fiber - optic Cable:
Adv:
Very High Bandwidth
Relatively inexpensive (depends on industry?)
Difficult to tap (good security)
Disadv:
Difficult to work with (difficult to splice)
Ethernet
Common LAN Protocol
Many orgs use 100-Gigabit Ethernet, where network provides data transmission speeds of 100 gigabits (100 billion bits) per second
Transmission Control Protocol/internet Protocol (TCP/IP)
4 Layers
Packet Switching
Network Protocols:
Internet Protocol (IP)
Is Responsible for DIsasembling, DElivering + REassembling the data during transmission
Packets
Before data are transmitted over the Internet, they are divided into small, fixed bundles called packets
i.e HELLO! = divided into 6 packets, P1 = H, P2 = E, P3 = L…. P6 = !
Packet Switching
The transmission tech that breaks up blocks of data into packets
i.e. Someone send message from NYC –> LA
It broken up into packets + go through diff routes and get to LA (diff internet centers?)
Packet Switching P2
Each packet carries info that will help it reach it’s destination, i.e.:
The sender’s IP adress
Th eintended recievers IP Adress
of packets i the message
+ # of the particular packet within the message
Packet Switching P3
Each Packet travels Independently across the network + can be found through diff paths in the network
When packets reach their destination, they reassembled into original message
3 Basic Functions of TCP
- Manages the movement of Data packets between compu’s by establishing a connection between the compu’s
- Sequences the transfer of packets
- Acknowledges the packets that have been transmitted
4 Layers of TCP/IP Reference Model
- Application Layer:
Enables client application programs to access the other layers + it defines the protocols that applications (apps) use to exchange data
- Transport Layer:
Provides the app layer with Communication + Packet Services
- Internet Layer:
Responsible for ADdressing, ROuting, + PAckaging Data Packets
ADROPA
- Network Interface Layer:
Places packets on + receives them from, the network medium which can be any networking tech
Sender moves down from Application + Network interface
Receiver goes from Network Interface to Application (i.e when you send an email)
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