Network Devices - Explained

 

Network devices, or networking hardware, are physical devices that are required for communication and interaction between hardware on a computer network.

• Hub: A hub connects individual devices on an Ethernet network so that they can communicate with one another. The hub operates by gathering the signals from individual network devices, optionally amplifying the signals, and then sending them onto all other connected devices. Hubs operate at the physical layer (Layer 1) of the OSI model.

• Switch: Switches generally have a more intelligent role than hubs. A switch is a multiport device that improves network efficiency. The switch maintains limited routing information about nodes in the internal network, and it allows connections to systems like hubs and routers. Generally, switches can read the hardware address of incoming packets to transmit them to the appropriate destination. A switch operates at the data link layer (Layer 2) of the OSI model.

• Router: Routers can filter traffic so that only authorized personnel can enter restricted areas. They can permit or deny network communications with a particular website. They can recommend the best route for information to travel. Routers are intelligent devices, and they store information about the networks they are connected to. Routers operate at the network layer (Layer 3) of the OSI model.

• Bridge: A bridge connects two or more networks or segments of the same network. The basic role of a bridge in network architecture is storing and forwarding frames between the different segments that the bridge connects. They use hardware media access control (MAC) address for transferring frames. Bridge operates at the data link layer of the OSI model.

• Gateway: It normally works at the transport and session layers of the OSI model. At the transport layer and above, there are numerous protocols and standards from different vendors; gateways are used to deal with them. Gateways provide translation between networking technologies such as Open System Interconnection (OSI) and Transmission Control Protocol/Internet Protocol (TCP/IP).

• Modem: Modems (modulators-demodulators) are used to transmit digital signals over analog telephone lines. Thus digital signals are converted by the modem into analog signals of different frequencies and transmitted to a modem at the receiving location. The receiving modem performs the reverse transformation and provides a digital output to a device connected to a modem, usually a computer. Modems work on both the physical and data link layers.

• Repeater: A repeater is an electronic device that amplifies the signal it receives. It works on the physical layer.

• Access Point: An access point works at the second OSI layer, data link layer, and it can operate either as a bridge connecting a standard wired network to wireless devices or as a router passing data transmission from one access point to another.