Computer Networks

The Network layer (Layer 3) handles logical addressing (IP) and routing, which allows data to move between different networks.

The Data Link layer (Layer 2) uses physical (MAC) addresses to deliver data between devices on the same local network, which is the primary function of a switch.

The Transport layer in the TCP/IP model is responsible for host-to-host communication, ensuring data delivery between processes on different hosts.

The Transport layer is responsible for segmenting data, managing end-to-end connections, and using port numbers to direct traffic to the correct application.

Layer 2 (Data Link) switches use MAC address tables to forward data frames to the correct destination port within a local network.

The Data Link layer is responsible for node-to-node data transfer and includes the Media Access Control (MAC) sublayer. This sublayer manages how devices gain access to the medium to transmit data.

The Network layer is responsible for logical addressing and routing across different networks, which is the core function of the Internet. It uses IP addresses to direct data packets.

The Network layer is responsible for routing data packets between different networks using logical IP addresses. This is the primary function of routers.

The Presentation layer acts as a translator for the network. It handles data formatting, encryption, and compression to ensure that data sent from the application layer is readable by the receiving system.

While basic switches operate at the Data Link layer (Layer 2), an intelligent or multilayer switch often performs routing functions, which places it at the Network layer (Layer 3).

ARP (Address Resolution Protocol) operates at the Data Link layer (or between Layer 2 and 3) to map IP addresses to MAC addresses. FTP, SSL, and NFS operate at higher layers (Application or Presentation).

The OSI model layers are: 1 Physical, 2 Data Link, 3 Network, 4 Transport, 5 Session, 6 Presentation, 7 Application.

The Session layer is responsible for establishing, managing, and terminating connections between applications, which is Layer 5 of the OSI model.

The Data Link layer is Layer 2 of the OSI model, situated directly above the Physical layer.

The Transport layer is Layer 4 of the OSI model, responsible for end-to-end communication and error recovery.