APCSP Internet Protocols

TCP/IP (Transmission Control Protocol/Internet Protocol)

• Foundational protocol suite for the Internet, enabling communication between devices.

• Consists of two main protocols:

  • TCP: Ensures reliable data transmission.

  • IP: Handles addressing and routing.

• TCP breaks data into packets, manages their delivery, and reassembles them at the destination.

HTTP (Hypertext Transfer Protocol)

• Protocol used for transferring hypertext (web pages) over the Internet.

• Operates on a request-response model, where a client (browser) requests resources from a server.

• Stateless: Each request is independent and does not retain session information.

HTTPS (Hypertext Transfer Protocol Secure)

• Secure version of HTTP, using encryption (SSL/TLS) to protect data during transmission.

• Ensures:

  • Data integrity

  • Confidentiality

  • Authentication between the client and server

• Essential for secure online transactions and protecting sensitive information.

DNS (Domain Name System)

• Translates human-readable domain names (like www.example.com) into IP addresses.

• Acts as the Internet's phonebook.

• Operates through a hierarchical structure with multiple levels of servers to resolve queries.

IP addressing (IPv4 and IPv6)

• IP addresses are unique numerical labels assigned to each device on a network.

• IPv4:

  • Uses a 32-bit address format.

  • Allows for approximately 4.3 billion unique addresses.

  • Addresses are nearly exhausted.

• IPv6:

  • Successor to IPv4.

  • Uses a 128-bit address format.

  • Vastly increases the number of available addresses.

FTP (File Transfer Protocol)

• Standard network protocol used to transfer files between a client and a server over the Internet.

• Supports both anonymous and authenticated access.

• Operates on a client-server model.

• Can use either active or passive modes for data transfer.

SMTP (Simple Mail Transfer Protocol)

• Protocol used for sending and relaying email messages between servers.

• Operates primarily over TCP port 25.

• Responsible for the delivery of outgoing mail.

• Not used for retrieving emails; it only handles the sending process.

POP3 (Post Office Protocol version 3)

• Protocol used by email clients to retrieve emails from a mail server.

• Downloads emails to the client and typically deletes them from the server, allowing offline access.

• Simple and effective for users who access their email from a single device.

IMAP (Internet Message Access Protocol)

• Protocol that allows email clients to access and manage emails directly on the mail server.

• Supports multiple devices, enabling users to view and organize their emails without downloading them.

• Retains emails on the server, allowing for synchronization across devices.

UDP (User Datagram Protocol)

• Connectionless protocol used for transmitting data without establishing a connection.

• Faster than TCP but does not guarantee delivery, order, or error correction.

• Suitable for real-time applications.

• Commonly used for:

  • Streaming media

  • Online gaming

  • Voice over IP (VoIP) services