Computer Networks

TCP is a connection-oriented protocol, meaning it establishes a formal connection (the three-way handshake) before data transfer begins to ensure reliability.

The Application Layer is the highest layer in the OSI model, making it the one that interacts directly with software applications used by the user.

At the Data Link Layer, data is encapsulated into frames. Packets are associated with the Network Layer, and bits are associated with the Physical Layer.

The Data Link Layer is divided into the Media Access Control (MAC) sublayer and the Logical Link Control (LLC) sublayer.

SSH (Secure Shell) is the standard protocol used for secure, encrypted remote command-line access to devices. Telnet is unencrypted, and TFTP is for simple file transfers.

The Presentation Layer (Layer 6) is responsible for data translation, compression, and encryption/decryption to ensure the Application Layer can read the data.

The Host-to-Host layer of the TCP/IP model corresponds to the Transport Layer of the OSI model, as both are responsible for end-to-end communication.

Telnet is a legacy protocol that uses TCP port 23 for remote terminal access.

Switching, specifically Layer 2 switching based on MAC addresses, occurs at the Data Link Layer of the OSI model.

HTTPS (HTTP over TLS/SSL) uses TCP port 443 by default for secure web communication.

TCP port 143 is the standard port assigned to IMAP (Internet Message Access Protocol), which is used for retrieving email from a server.

POP3 is a standard mail protocol used to receive emails from a remote server to a local client. It is officially assigned to TCP port 110.

DNS is used to resolve domain names into IP addresses. It primarily uses port 53 for both UDP and TCP queries.

SMTP is the standard protocol for sending emails across the internet. It is assigned to port 25.

Telnet is an older protocol used for remote terminal access. It operates on port 23.