Layers of the Internet Flashcards
what problem does physical network solve? how does it work?
Physically connecting devices to one another so that information can move through the network.
Fiber optic cables, wifi signals, or copper wires physically connect the computers, smart phones, servers, etc. that make up the Internet. Computers don’t need to be directly connected to each other, just a single point on the network.
what problem does IP: Internet Protocol solve? how does it work?
Uniquely identifying people
on the internet and routing
messages between them.
Each device on the internet is given a unique IP address. Packets
sent on the internet include to and from IP addresses. Routers
along the way use this information to move data along a path of
direct connections. Routing happens dynamically, meaning the path
is unpredictable and changes based on network conditions
what problem does TCP: Transmission Control Protocol solve? how does it work?
Send large messages over
the Internet when accuracy
is most important. You
would either use TCP or
UDP.
Messages are divided into packets and sent all at once. Packets
are numbered so that they can be re-ordered and missing packets
can be requested by the receiver. TCP is slower than UDP because
error checking like this takes more time, but it is much more
reliable.
what problem does UDP: User Datagram Protocol solve? how does it work?
Send large messages over
the Internet when speed is
most important. You would
either use TCP or UDP.
Messages are divided into packets and sent all at once. There is no
error-checking to ensure all packets arrive or that they’re in order.
UDP is faster than TCP but more errors are possible. This is useful
for streaming video or online gaming because having the picture
displayed quickly is more important than it being displayed with a
perfectly clear picture
what problem does DNS: Domain Name System solve? how does it work?
Translate human-readable
domains like code.org or
example.com into IP
addresses that can be
used by the Internet.
When you try to go to a domain like example.com, you computer
first contacts a system of servers collectively called the DNS which
keeps track of the IP addresses associated with each domain
name. Communication with DNS servers happens over the
Internet, meaning the request to and from servers are sent as TCP/
IP packets
what problem does HTTP: HyperText Transfer Protocol solve? how does it work?
Allow computers to request
and share webpages,
audio, images, videos, and
other file types on the
Internet, collectively known
as the world wide web.
Computers communicate in plain text like GET to request files or
send data. The server that receives the request responds with the
files requested which are displayed by your browser. HTTP
requests are sent between computers over the internet as part of
TCP/IP packets. The world wide web is just files that are requested
using HTTP and sent over the Internet
