IT2101: Communication Technology

4. Common Network Devices / Hardware

Program: BSCS I (January Semester – 2014)Lecturer: Rebecca Asiimwe

Email: rasiimwe@technology.ucu.ac.ug

Network Devices

• Network devices are tangible parts of a computer Network that facilitate communication between nodes on the network.

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Common Network Hardware

• These are equipment that facilitate the use of computer networks.

They include:-A Router - A Gateway

-A Switch - A Hub

-Access point - A bridge

-Network Interface Card - Modem

-Networking cables - A Firewall

e.t.c…

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The NIC

• A network card, network adapter or Network Interface Card (NIC) is a piece of computer hardware designed to allow computers to communicate over a computer network.

• Provides a low-level addressing system through the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly.

• The NIC is both an OSI layer 1 (physical layer) and layer 2 (data link layer)device.

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NIC

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Hubs

• A hub contains multiple ports. When a packet arrives at one port, it is copied to all the ports of the hub.

• This means that a communication will be exposed to all other connected nodes to the Hub.

• It connects multiple devices together & makes them act like a single network segment.

• Note: The difference between a Hub and a Switch in Networking.

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Hubs

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Switches

• A small hardware device that joins multiple computers together within one Local Area Network (LAN).

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Switches

• These are capable of inspecting data packets as they are received, determining the source and destination device of that packet, and forwarding it appropriately.

• This is the main difference between them and the Hubs.

Question:

• What is a Switching Hub?

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Firewall

A firewall is a device or set of devices designed to permit or deny network transmissions based upon a set of rules and is frequently used to protect networks from unauthorized access while permitting legitimate communications to pass.

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Firewall - Front

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Firewall - Back

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A Router

• Is a device that extracts the destination of a packet it receives, selects the best path to the destination and forwards data packets to the next device along the path.

• Note: Routers connect networks together: e.g. LAN to WAN to access the internet

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A Router Cont’d

• Routers forward data packets along networks by using headers and forwarding tables to determine the best path to forward the packets.

• Routers work at the network layer (layer 3) of the OSI model (OSI is to be discussed in a later lecture)

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Routers

Switches

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A Repeater

• A repeater is an electronic device that receives a signal and retransmits it at a higher level or higher power.

• This helps in regenerating the signal since it gets weak as it travels further from its origin.

• This process (weakening of the signal as it travels further from its point of origin) is called attenuation

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Research About:

• A Bridge

• A Brouter

• A Gateway

• An Access point

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Q & A