The Internet and the Worldwide Web Flashcards
What is the internet?
It is the physical infrastructure of all the computers networked together around the world
How does the internet send data?
using “packets”
What does www stand for?
World Wide Web
What is the world wide web?
information space that sits on top of internet
What does URL stand for?
Uniform Resource Locator
What does OSI stand for?
Open System Interconnection
What is OSI?
set of standards describing the different layers of communication
What are the stages of the TCP/IP Model?
- Physical Layer
- Datalink Layer
- Network Layer
- Transport Layer
- Application Layer
What happens in the physical layer?
Means of transmitting raw bits
wired/wireless
e.g. wifi ,bluetooth,USB
What happens in the data link layer?
creates frames made of packets
What happens in the network layer?
creates packets
uses IP address to find packet sources and destinations.
What does IP stand for?
Internet Protocol
What does IP do?
Has destination address in it
doesn’t know who to send it to
What happens in the transport layer?
Establishes the connection between applications running on the different host
Uses TCP for reliable connections
Uses UDP for fast connections
What does UDP stand for?
User Datagram Protocol
What does UDP do?
Has own header which sits inside the data payload.
Header has port number which is checked to determine which application to send data to.
Checksum checks sum
It just discards corrupted packets
packets take quickest route
What is the Physical Layer in the TCP/IP model?
Means of transmitting raw bits (wired/wireless).
Examples: Wifi, Bluetooth, USB
What does the Datalink Layer do?
Creates frames to move across the network. Frames are made of packets.
What is the role of the Network Layer?
Responsible for creating the packets to move across the network.
What is the Internet Protocol (IP)?
There is not much more than the destination address in the packet, allowing it to reach its destination without knowing the application to send it to.
What is the purpose of the Transport Layer?
Establishes a connection between applications on different hosts.
What is UDP?
User Datagram Protocol; a simple, common, fast connection with a header that contains a part number and a checksum to verify data.
What happens to corrupted packets in UDP?
Corrupted packets are discarded; UDP trades reliability for speed.
What are some examples of applications using UDP?
Streaming, Skype, Gaming.
What is TCP?
Transmission Control Protocol; reliable connection with a destination part, checksum, and sequential numbers.
What is the purpose of the sequence number in TCP?
Allows packets to be sent in the correct order.
What protocols are included in the Application Layer?
HTTP, HTTPS, DNS, SMTP.
What is HTTP?
Hypertext Transfer Protocol; a protocol to transfer hypertext containing links to other web pages.
What is HTTPS?
Hypertext Transfer Protocol Secure; data is encrypted for online payments or banking.
