Transcript A Router

IT2101: Communication
Technology
4. Common Network Devices
/ Hardware
Program: BSCS I (January Semester – 2014)
Lecturer: Rebecca Asiimwe
Email: [email protected]
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 Switch
-Access point
-Network Interface Card
-Networking cables
- A Gateway
- A Hub
- A bridge
- Modem
- 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