CSE32P4
Computer Networks Lab
Lab#1: Introducing with the Network Devices
Sumaya Kazary
Assistant Professor
Department of Computer Science and Engineering
Dhaka University of Engineering & Technology, Gazipur
Acknowledgement
Thanks to the authors of all the books and online tutorials used in this slide.
Network Devices
❑ Components to connect computers to other devices
together so that they can share files/resources like
printer/Fax.
❑ NIC
❑ Repeater
❑ Hub
❑ Bridge
❑ Switch
❑ Router
NIC (Network Interface Card)
➢ Also called Network Adapter.
➢ It connects a host to a network medium.
➢ It provides the physical interface between
computer and cabling.
➢ It prepares data, sends data, and controls the flow
of data.
➢ It can also receive and translate data into bytes
for the CPU to understand.
➢ Contain unique MAC Address to control data
communication.
Repeater
Two port device , functioning at PHY Layer
A repeater is an electronic device that receives a
signal and Regenerates it at a higher level and/or
higher power
◦ so that the signal can cover longer distances.
It removes Noise from the received signal
◦ then regenerates the original bit pattern/signal
◦ then sends the refreshed signal.
No Filtering of signal
◦ Broadcast the regenerated signal to all ports.
Hub
It is basically a MULTI-port Repeater
Functioning at PHY Layer
A hub connects multiple wires coming from
different branches
No Filtering of signal
◦ Broadcast the regenerated signal to all ports.
Active Hub
These are the hubs that have their own power
supply
It serves both as a repeater as well as a wiring
centre.
Can clean, boost, and relay the signal along with
the network.
These are used to extend the maximum distance
between nodes.
Passive Hub
These are the hubs that collect wiring from
nodes
No own Power Supply
◦ Power supply from the active hub.
These hubs relay signals onto the network
without cleaning and boosting them
Can’t be used to extend the distance between
nodes.
Intelligent Hub
It works like active hubs
Includes remote management capabilities.
They also provide flexible data rates to network
devices.
It also enables an administrator to monitor the
traffic passing through the hub and to configure
each port in the hub.
Bridge
A bridge operates at the DLL (Layer 2 of the OSI model)
Bridges connects two or more different LANs that has a
similar protocol and provides communication between the
devices (nodes) in them.
Filtering of traffic : On the basis of MAC Address
On receiving a Data Frame, the bridge consults a database
(MAC Table) to decide whether to pass, transmit or discard
the frame.
◦ If the frame has a destination MAC address in the same
network, the bridge passes the frame to that node and
then discards it.
◦ If the frame has a destination MAC address in a
connected network, it will forward the frame toward it.
Bridge
Switch
A Switch operates at the DLL (Layer 2 of the OSI
model)
It is an intelligent network device that can be
conceived as a multiport network bridge.
Switch connects two or more different LANs that has a
different protocol and provides communication
between the devices (nodes) in them
It uses MAC addresses to send data packets to selected
destination ports.
Filtering of traffic : On the basis of MAC Address
Router
A Router operates at the NWL (Layer 3 of the OSI model)
A router is a device that routes data packets based on their
IP addresses.
It connects different networks together and sends data
packets from one network to another.
Routers have a dynamically updating routing table based
on which they make decisions on routing the data packets
In order to prepare or refresh the routing table, routers
share information among each other
Routers are more expensive than other networking devices
like hubs, bridges and switches.
Thank You
