Basic Networking Terminology Cont Repeaters Repeaters are the

Basic Networking Terminology (Cont. )

Repeaters • Repeaters are the devices that are used to amplify or regenerate the digital signals that they receive, while sending them to different parts of the network. Before transmitting the signals to different parts of the network they remove unwanted noise from the incoming signals. • Repeaters are used to extend LAN. They have only two ports that connect two networks. They are useful if the computers in the network are located at longer distances. However, repeaters do not have any built in intelligence, so, they propagate the errors, if it is there, in the original signal. • In a wireless network the repeaters consist of radio receivers, transmitters, amplifiers, isolators and antennas.

Hubs • A hub is a small, inexpensive device that is used to join multiple computers in a computer network. It contains multiple ports and it is used to connect segments of a LAN. • A hub never examines or manages the traffic that comes through it. Any signal that enters any port is rebroadcasted by the hub on all the other ports. • However, there are intelligent hubs also that include additional features that enables an administrator to monitor the traffic that passes through the hub. The administrator can configure each port in the hub.

Switches • Switches are the devices that are used to join multiple computers in a network. • They differ from hubs as switches are more intelligent than hubs. Switches have the capability to inspect the data packets (small formatted parts of the data to be transmitted) that they receive and also, they determine the source device from where the packets are transmitted and the destination device where the packets are to be sent. • After determining the source and the destination devices they forward the data packets appropriately.

Bridges • A bridge is a networking device that is used to connect two LANs that use the same protocol. It reduces the data traffic on a LAN by filtering it and dividing it into two segments. • Bridges operate at the data link layer (layer 2) of the OSI model. They inspect the incoming data traffic to decide whether to forward the data or discard it. • Bridges serve the similar functions as switches. However, traditional bridges support only one network boundary, while switches offer four or more hardware support, that is why some times switches are called multi-port bridges.

Routers • Routers are the network devices that are used to connect multiple similar wired or wireless networks. Routers are generally used in large inter networks that uses TCP/IP protocol suite. They forward data packets from one logical network to another. • Routers have better packet routing and filtering capabilities and greater processing power.

Firewall • A firewall is a system in the Local Area Network that is designed to allow or deny a network transmission based on a set of pre-defined rules. • It prevents unauthorized access to the organization’s network by the unauthorized internet users. • All the messages that try to enter or leave the organization’s network pass through the firewall. The firewall then examines the messages on the basis of the set of rules defined and then allows or blocks the message.

Ethernet • Ethernet is a networking technology widely used for physically connecting computers together in Local Area Network (LAN). • Its used to connect computers in an office, school, college, etc. to form a LAN as well as it is used to connect a home-PC to connect to internet using a cable modem or DSL modem. • It makes use of a network cable with RJ-45 connector, a network hub or network switches and a network adaptor card to form a LAN. However, it can form a LAN without cable also using “Wi-Fi” card. • Ethernet supports a data transmission speed up to 100 mbps (mega bits per second).