Network+Devices

Network Devices  Back To make data transmission more extensible and efficient than a simple peer-to-peer network, network designers use specialized network devices, such as hubs, switches, routers, and wireless access points, to send data between devices. Hubs

Hubs are devices that extend the range of a network by receiving data on one port, and then regenerating the data and sending it out to all other ports. This process means that all traffic from a device connected to the hub is sent to all the other devices connected to the hub every time the hub transmits data. This causes a great amount of network traffic. Hubs are also called concentrators, because they serve as a central connection point for a LAN.



Bridges

LANs are often divided into sections called segments, similar to the way a company is divided into departments. The boundaries of segments can be defined using a bridge. A bridge is a device used to filter network traffic between LAN segments. Bridges keep a record of all the devices on each segment to which the bridge is connected. When the bridge receives a frame, the destination address is examined by the bridge to determine if the frame is to be sent to a different segment or dropped. The bridge also helps to improve the flow of data by keeping frames confined to only the segment to which the frame belongs.



Switches

Switches are sometimes called multiport bridges. A typical bridge has two ports, linking two segments of the same network. A switch has several ports, depending on how many network segments are to be linked. A switch is a more sophisticated device than a bridge. A switch maintains a table of the MAC addresses for computers that are connected to each port. When a frame arrives at a port, the switch compares the address information in the frame to its MAC address table. The switch then determines which port to use to forward the frame.



Routers

Whereas a switch connects segments of a network, routers are devices that connect entire networks to each other. Switches use MAC addresses to forward a frame within a single network. Routers use IP addresses to forward frames to other networks. A router can be a computer with special network software installed, or a router can be a device built by network equipment manufacturers. Routers contain tables of IP addresses along with optimal destination routes to other networks.



Wireless Access Points

Wireless access points provide network access to wireless devices such as laptops and PDAs. The wireless access point uses radio waves to communicate with radios in computers, PDAs, and other wireless access points. An access point has a limited range of coverage. Large networks require several access points to provide adequate wireless coverage.



Multipurpose Devices

There are network devices that perform more than one function. It is more convenient to purchase and configure one device that serves all of your needs than to purchase a separate device for each function. This is especially true for the home user. In your home, you would purchase a multipurpose device instead of a switch, a router, and a wireless access point. The Linksys 300N is an example of a multipurpose device.

Summary

Network designers use special network devices to provide connectivity. These are the most common network devices: <span style="font-family: Georgia,serif; font-size: 120%;">· Hub <span style="font-family: Georgia,serif; font-size: 120%;">It helps in extending the range of the network by receiving the data, then regenerating it and sends it out to all devices that are connected with.

<span style="font-family: Georgia,serif; font-size: 120%;">· Bridge <span style="font-family: Georgia,serif; font-size: 120%;">It used to filter the network traffic between LANs. It keeps a record with all devices that are connected to it. Therefore, when the bridge receives a packet, it examines to determine if the packet to be sent to anther LAN or not.

<span style="font-family: Georgia,serif; font-size: 120%;">· Switch <span style="font-family: Georgia,serif; font-size: 120%;">It differs from the bridge that bridge has two ports, while the switch has several ports to connect many LAN segments. Unlike the hub, when switch receive a message to be sent to specific device, it compare the address of the message to its MAC address table to determine which device has this Mac address.

<span style="font-family: Georgia,serif; font-size: 120%;">· Router <span style="font-family: Georgia,serif; font-size: 120%;">It connects the whole network to each other. It uses IP address to know which device should receive the message that router received it before.

<span style="font-family: Georgia,serif; font-size: 120%;">· WAP <span style="font-family: Georgia,serif; font-size: 120%;">It helps to connect wireless devices like laptops and PDAs to a network. It uses radio waves for the communication between the wireless devices and other WAP. For large networks, it is needed to have several WAPs because WAP has limited range of coverage.

<span style="font-family: Georgia,serif; font-size: 120%;">· Multipurpose device <span style="font-family: Georgia,serif; font-size: 120%;">This device can do more than one function. It helps in saving our money by buying one device can to functions of multiple devices.

<span style="font-family: 'Comic Sans MS',cursive; font-size: 12pt;">Resource

<span style="font-family: Georgia,serif; font-size: 120%;">CISCO Networking Academy Program Website