Layer Name

Layer Function

Sample Protocol

Hardware

Application Layer

The Application Layer represents the services, that directly support the user applications such as programs for web browsing,  email, file transfers, etc.

SNMP, SMTP, FTP, HTTP Data

Presentation Layer

The Presentation Layer converts incoming and outgoing data from one presentation format to another. This layer also include data encryption and text compression.

MIME, SSL, TLS Data

Session Layer

The Session Layer opens, manages, and closes conversations between two computers. It also performs name recognition and the functions like security, needed to allow two applications to communicate over the network, also provides error handling.

NetBIOS,  RTP, RPC Data

Transport Layer

The Transport Layer provides transparent transfer of data between hosts, and its responsibilities include end-to-end error recovery and flow control. It also ensures complete data transfer, Sequencing of data packets, and requests retransmission of missing packets. It can also repackage messages for more efficient transmission over the network.

TCP, UDP Segment

Network Layer

The Network Layer establishes, maintains and terminates network connections. It also routes data packets across network segments and translates logical addresses and names into physical addresses.

IP, IPX, ARP Packet

Routers

Data Link Layer

The Data Link Layer transmits frames of data from computer to computer on the same network segment. This layer ensures the reliability of the physical link established at Layer 1. These standards define how data frames are recognized and provide the necessary flow control and error handling at the frame set. This layer is divided into two sublayers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. The MAC sublayer controls how the computer on the network gets access and permission to the data to be able to transmit it. The LLC layer controls frame synchronization, flow control and error checking.

PPP, Frame Relay, bridges and switches

Network interface cards

Physical Layer

The Physical layer defines all the electrical and physical specifications for devices. This includes the layout of pins, voltages, and cable specifications. This layer defines cabling and connections. It also transmits data over the physical media.

Hubs, repeaters, network adapters, Cat 5, Fiber Optic Bits

Wires, Network adapter

Application Layer

The Application Layer is the application software used by the network user and includes a lot of what the OSI model has in the application, presentation, and session layers. It gives user's access to the network and by using the application software, the user can define what messages are being sent over the network

HTTP, HTML, Browsers(Internet Explorer, Safari, Firefox, Chrome, Opera), Messengers, SMTP, IMAP, POP Data

Transport Layer

The Transport Layer is responsible for linking the application layer software to the network and establishing end-to-end connections between the sender and receiver when those connections are needed. Other responsibilities include breaking long messages into several smaller messages to make them easier to transmit and then later recombining messages back into the original larger message at the receiving end. it can also detect lost messages and request that they be resent

TCP, SPX, Packets Segment

Network Layer

The Network Layer performs routing, selecting the next computer to which the message should be sent. Also it can find the address of that computer if it doesn't already know it.

IP, IPX, Gateways, routers Packet

Data Link Layer

The Data Link Layer is responsible for moving a message from one computer to the next in the network path from the sender to the receiver. It also controls the physical layer by deciding when to transmit messages over the media. It then formats the messages by indicating where they start and also end. It detects and sometimes correct any errors that may have occurred during transmission of the message.

Ethernet, MAC addresses, ARP, Switches Frame

Routers

Physical Layer

The Physical Layer is the actual physical connection between the sender and receiver. The role of this layer is to transfer a series of electrical, radio, or light signals through the circuit. The physical layer specifies the type of connection that can pass through it.

Cat 5 , Fiber Optic

Wires, network interface cards