Circuit switching is a method of establishing a dedicated communication path between two devices before data transmission. Elaboration: Example: A landline telephone call reserves a circuit for the entire call duration.

Packet switching is a method of data transmission where messages are broken into packets and sent individually over the network. Elaboration: Example: When sending an email, the message is broken into packets, each taking different routes, and reassembled at the destination.

Forwarding is the process of directing incoming data packets to the correct output port based on the routing table. Elaboration: Example: A router receives a packet, looks up the destination IP, and forwards it to the next hop.

Routing is the process of determining the best path for data packets to travel across networks. Elaboration: Example: When you access google.com, routers determine the shortest path to Google’s server.

NAT (Network Address Translation) is a technique used to translate private IP addresses into a public IP, allowing multiple devices to share a single external IP address. Elaboration: Example: A home router assigns private IPs (192.168.1.x) to devices while using a single public IP to access the internet.

A VPN (Virtual Private Network) is a secure communication channel that encrypts internet traffic and allows users to access private networks remotely. Elaboration: Example: A company employee connects to a corporate VPN to securely access internal company resources.

ICMP (Internet Control Message Protocol) is a network layer protocol used to send error messages, diagnostics, and operational queries. Elaboration: Example: A ping command uses ICMP to check the availability of a host: bashCopyEditping google.com

TCP (Transmission Control Protocol) is a connection-oriented transport layer protocol that ensures reliable, ordered, and error-checked data transmission. Elaboration: Example: Web browsing, file downloads, and secure email transmissions rely on TCP. Code Example: (TCP Client) pythonCopyEditimport socket client = socket.socket(socket.AF_INET, socket.SOCK_STREAM) client.connect((“example.com”, 80)) client.send(b”GET / HTTP/1.1\r\nHost: example.com\r\n\r\n”) print(client.recv(1024).decode()) client.close()

UDP (User Datagram Protocol) is a connectionless transport layer protocol that sends data without establishing a connection, making it fast but unreliable. Elaboration: Example: Online multiplayer games like PUBG or Fortnite use UDP for real-time data transmission. Code Example: (Simple UDP Server) pythonCopyEditimport socket server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) server.bind((“0.0.0.0”, 12345)) data, addr = server.recvfrom(1024) print(f”Received…

SMTP (Simple Mail Transfer Protocol) is an internet standard protocol used for sending and relaying emails between mail servers. Elaboration: Example: When you send an email via Gmail, your client uses SMTP to send the message to the recipient’s mail server. Code Example: (Sending an email using Python’s smtplib) pythonCopyEditimport smtplib server = smtplib.SMTP(“smtp.example.com”, 587)…