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Internet Protocols (Ch17) - Coggle Diagram
Internet Protocols (Ch17)
Transport layer protocols
TCP
Transmission Control Protocol (
reliable
)
most widely used protocol
do a lot of work in data error checking and correction (need more resources)
therefore no data loss
some
latency
e.g. Web browsing, file transfer
guaranteed user experience
file is not sent in one piece but split into small pieces called
packets
packets are reassembled on the receiving side
If data loss during transmission, then resend data, resolve missing or corrupted data
TCP packet header information (complicated)
Packet analyzer
https://youtu.be/r0l_54thSYU
TCP/IP model
https://edu.cospaces.io/MND-EKW
UDP
User Datagram Protocol (
unreliable
)
data are send in chains like machine gun, simple protocol
data loss exist
no error control
low latency
e.g. Live real-time connections, video calls, voice calls, on-line games, drones
UDP packet header information (simple)
Protocol
a set of rules (basic laws) governing the communication of network devices
just like two persons agree on certain rules (e.g. language, name of app) before they can communicate through instant messaging (IM)
Network layer protocol
IP
Internet Protocol
delivering the packets to destination
adding IP addresses to packets
choosing the shortest path to destination
IP addresses
unique identifier assigned to each networked device
analogy: postal service, IP address is similar to the address written on the envelope of a letter to be sent
Version
IPv6
designed to replace IPv4
128 bit address
IPv4
32 bit address (only)
Checking IP address of your PC
4,294,967,296 version 4 addresses were used up, then can we still workout IoT (Internet of Things)?
Privacy
Private
IP address
used in local network
unique within the same network
e.g. home network
Public
IP address
used in Internet, unique across Internet
assigned by
ISP
(Internet Service Provider)
What if someone know your public IP address? Can they know your location?
This video shows how vulnerable your home network is and how to protect it
https://youtu.be/80vIin4xGp8
Router
forwards data packets between computer networks
Application layer protocols
Web browsing
HTTPS
Hypertext Transfer Protocol Secure, provide secure communication
encrypted using Transport Layer Security (
TLS
), formerly Secure Sockets Layer (
SSL
)
HTTP
Hypertext Transfer Protocol
web browsing
Email
Sending email
SMTP
Simple Mail Transfer Protocol
sending email
Retrieving email
IMAP
Internet Message Access Protocol
synchronize all email folders with email client computer (more advance)
user can
store
email messages on email server after retrieving them
POP3
Post Office Protocol
simple protocol, only download inbox messages to email client computer
email messages are
deleted
from the email server after user retrieval
Gmail advance settings
FTP
File Transfer Protocol
transferring files between computers
DNS
(Domain Name System)
people can remember domain names, but not IP addresses
therefore need service (Domain Name Server) to translate/resolve domain names to IP addresses
How many top level domains (TLD) are there?
When and where to buy a domain name?
How to check whether a domain name is real or not? checking the owner?
URL
(Uniform Resource Locator)
web address 網址
e.g.
https://sites.google.com/view/tlonlinelearning/home
Data link layer
Ethernet
IEEE 802.3 standard
Switch
connects devices on a computer network by sending and receiving packets
Physical layer
cables, network interface card (NIC)
