Physical Layer Devices

This layer is responsible for the physical connection among two or more devices hence this layer uses the majority of networking devices are as follows:

• Hub - This is a mostly used device for the connection of LAN networks. It can categorize as Passive hub, Active hub, and intelligent hub.

• Repeater - This is used in transmission systems to regenerate analog or digital signals.

• Cables and Connector - It is widely used to connect multiple devices with the help of different types of cables such as Copper cable, Coaxial cable, Ethernet cable, Shielded Twisted Pair Cable, Unshielded Twisted Pair Cable.

• Modem - This is a hardware component that helps to send and receive information over the telephone line.

• Network Interface Card (NIC) - This allows a computer system to make a connection with the network system.

• Transmitter - This is used to deliver radio waves through an antenna.

• Receiver - This is used to receive signals like analog electromagnetic signals or waves, or digital signals.

• Transceiver - This performs both functions of transmitter and receiver for analog or digital signals.

• Couplers - These are furnished with mandatory protection equipment to secure the equipment when being unmated and in-service and to prevent calcareous buildup and marine growth.

Data Link Layer Devices

This layer transfer data hop by hop hence uses the networking devices are as follows:

• Bridge - This provides interconnection with other networks that use the same protocol, connecting two different networks and providing communication between them.

• Switch - This uses MAC addresses to forward data at the data link layer. Sometimes it is also used at the network layer to forward the data and is called layer-3 switches or multilayer switches.

Network Layer Devices

This layer performs major functionality of routing like creating routing tables and deciding the suitable route to deliver the data hence uses the networking devices are as follows:

• Routers - This is similar to switch but it is used to route or forward the data packets based on their IP addresses. It connects LANs and WANs. Update routing table dynamically based on which they make decisions on routing the incoming packets.

• Brouters - This is a bridge router or brouter that works as a bridge and as a router also because it combines features of both bridge and router. Working as a router, it is can route packets across networks, and working as a bridge, it can filter LAN traffic.

Transport Layer Devices

This layer provide end-to-end communication or process-to-process communication hence uses the networking devices are as follows:

• Gateway - This is a part of two networks, which use different protocols. It takes the data from one system, interpret it, and transfer it to another system. Hence, also called protocol converters and can operate at any network layer.

• Firewall - This is used to prevent unauthorized access to or from a private network. It provides packet filtering and proxy server facilities.

Application Layer Devices

This is the top-most layer of the TCP/IP and OSI model that provides the interface between the applications and network. Some of the networking devices used are as follows:

• Computers, Phones, Servers
• Gateways and Firewalls