Lecture 5 Flashcards
How do internet and web function:
1) packet switching and TCP-IP and IP adress
2) client server model
3) internet cloud computing model
How internet communication works - Packet switching
Method of slicing digital messages into packets (of a fixed size)
To be sent along different communication paths as these become available and
Reassembling the packets once they arrive at destination
The TCP-IP protocol has four layers
1) Application layer to exchange data between software applications
2) Transport layer to connnect internet to a software application
3) Internet layer to address packages and routing messages across internet
4) Network interface layer to place packages on and receiving packages from internet
IP adress
Every device connected to the internet must have a unique adress number called an internet protocol adress
Domain names
The domain names system allows expressions such as peasoned.com to stand for numeric IP locations
DNS server
DNS servers are databases that keep track of IP adresses and domain names on the internet
Root server:
Root servers are central directories taht list all domain names currently in use for specific domains; for example, the .com root server. DNS servers consult root servers to look up unfamiliar domain names when routing t raffic
IPv4
uses 32 bits to identify an address –> 2^32 = 4284967296 different IP addresses
Domain name
IP address expressed in natural language (not binary or decimal)
Domain name system (DNS) allows numeric IP addresses to be expressed in natural language
Uniform resource locator (URL)
Thick clients
Have their own (internal) computing power and storage for data and software
May also use cloud computing to store some data on/use some software from servers
Thin clients
use (cloud) servers (local and/or wide area networks) for computing and storage of data and software
Cloud computing
Clients obtain shared and standardized services over internet from various servers
Businesses (and consumers) need to know…
Where are my data
-In my device
-In my local network
-In the cloud
Where is my software
Where is my hardware
And is it still secure
Cloud computing is
On demand self service (obtain IT only when your business needs it)
Ubiquitous network access (use access anywhere, anytime)
Location independent resource pooling (share IT resources)
Rapid elasticity (increase or decrease IT as needed)
Measured service (pay per use, no need to invest)
Cloud computing offers firms to focus on
Using IT instead of
Buying and managing IT
Public cloud
Third party service offering computing, storage, and software services to multiple consumers
Private cloud
Cloud infrastructure operated soley from a single organization and hosted either internally or externally
Hybrid cloud
Combination of private and public cloud services that remain separate entities
Internet backbone
High-bandwidth fiber-optic cable networks
Private networks owned by a variety of NSPs
Bandwidth
Build in redundancy
Internet exchange points (IXPs)
Hubs where backbones intersect with regional and local networks, and backbone owners connect with one another
Tier 3 internet service providers (ISPs)
Provide end users (homes, businessess) connection to the internet and internet services
Internet of things
Use of the internet to connect a wide variety of devices, machines and sensors
Use existing technologies such as RFID (bank cards)
Fitbits, smart fridge, smart weight scales etc.)
smart TVs
Smart cars
Limitations of the current internet
Bandwidth limitations
quality of service limitations
Latency
Best effort QOS (no guaranteed delivery time of packages)
Network architecture limitations
Network performances low if many ask 1 service
First mile (server slide) - last mile (client side) congestions
Language development limitations
HTML (not really for rich texts, pictures, etc)
Wired internet limitations
Who governs the internet
ORganizations that influence the internet and monitor its operations include
Internet architecture board (IAB)
Internet corporation for assigned names and numbers (ICANN)
Internet engineering steering group (IESG)
Internet engineering task force (IETF)
Internet society (ISOC)
World wide web consortium (W3C)
