Internet Protocol Stack Flashcards
(10 cards)
five layers
Application Layer (e.g., HTTP, FTP)
Transport Layer (e.g., TCP, UDP)
Network Layer (e.g., IP, ICMP)
Link Layer (e.g., Ethernet, Wi-Fi)
Physical Layer (e.g., cables, radio signals)
Application Layer
Provides end-user services
HTTP (web browsing), FTP (file transfer), SMTP (email)
Transport Layer
Ensures reliable or fast data delivery between applications
TCP (reliable, connection-oriented), UDP (fast, connectionless)
Network Layer
Routes packets across multiple networks
IP (delivers packets), ICMP (error reporting)
Link Layer
Manages direct communication between connected devices
Ethernet (wired networks), Wi-Fi (wireless networks)
Physical Layer
Transmits raw bits over physical media
Fiber optics (light signals), Ethernet cables (electrical signals)
TCP (Transmission Control Protocol)
Connection established by three way handshake process between client and server
SYN :
Client sends tcp packet with:
syn flag =1
Random initial sequence number (SEQ = 2000)
SYN-ACK:
Server replies with:
SYN flag = 1
ACK flag = 1
New sequence number (SEQ = 4000)
Ack number = client seq + 1 (2001)
ACK:
Client confirms:
ACK flag= 1
ACK number = Servers Seq + 1 (4k)
Example:
(Browser) hi server I want to connect, my starting sequence number is 2000
(Server) ok. My sequence number is 4000, and I expect your next byte to be 2001.
(Browser) confirmed. Let’s transfer data
UDP (User Datagram Protocol)
No connection established before sending data
UDP sends data immediately without SYN, SYN-ACK, ACK
If packet is lost, UDP does not retransmit it
Packets may arrive out of order
TCP UDP difference
TCP:
Connection-oriented
Reliable delivery
Slower speed
UDP:
Connectionless
Unreliable delivery
faster speed
protocol
a standardized set of rules for network communication, ensuring proper data exchange
defines format, timing, sequencing and error control of data exchange (e.g., HTTP for web browsing)
