This document discusses various connectivity devices used in computer networks. It describes a transceiver as a device that can both receive and transmit signals. A repeater is used to regenerate incoming signals to maintain signal strength during transmission. A hub and switch are central devices in star networks that connect other devices, with the main difference being that a switch can deliver messages directly to the intended recipient while a hub broadcasts to all. A bridge connects two or more local area networks, while a router routes signals between similar networks and keeps routing information. A gateway interconnects dissimilar networks and is installed at the application layer.

1. CONNECTIVITY
DEVICES
By: PRINCE KUMAR

2. CONTENTS…
 COMPUTER NETWORK
 IDENTIFICATION OF A NODE IN THE
NETWORK
 MEDIA & CONNECTORS
 CONNECTIVITY DEVICES
 TRANSCEIVER
 REPEATER
 HUB
 SWITCH
 BRIDGE
 ROUTER
 GATEWAY

3. COMPUTER NETWORK
 A computer network is collection of interlinked
nodes.
 The goals for which a computer network is
established_
 Communication
 Resource sharing
 Reliable environment
 To achieve goals a network involves_
 Message : Data content.
 Sender and Receiver: Nodes
 Media : Any thing though which the message is
transferred from sender to receiver.
 Protocols : Certain algorithms to control
communication.

4. IDENTIFICATION OF A NODE IN
THE NETWORK
 Each Node has an address
through which it is identified in
the network.
 NIC [Network Interface Card]:
An special device connected
on the motherboard of the
computer having a 6 digit
hexadecimal address [MAC
Address] by which it is
identified by matching the
logical address[IP Address] at
network support layers .

5. MEDIA & CONNECTORS
 Any thing though which the message is
transferred from sender to receiver is called as
Medium.
 It may be_
 Unguided: Air or Vaccum space.
 Guided: A physical way or link between nodes.
 E .g; Twisted pair cable (STP, UTP with RJ
connectors), Coaxial cable (with RG connectors) and
Fibre Optics.

6. MEDIA & CONNECTORS
RJ45
RG

7. CONNECTIVITY DEVICES
 The devices used to establish a network are
known as CONNECTIVITY DEVICES.
 They may be categories as_
 Networking Devices
 Within a network; HUB, SWITCH etc.
 Internetworking Devices.
 Between two or more networks; BRIDGE, ROUTER
etc

8. TRANSCEIVER
 A device that is able to receive as well as
transmit signals is known as TRANSCEIVER.

9. REPEATER
 A device having
capacity to repeat or
regenerate the
incoming signals.
 To make the signals
strength constant
during transmission.
 It is installed at
Physical layer in the
network.

10. HUB
 A HUB is a device used as
a central device in star
networks.
 It broadcasts the message
in the entire network,
because it can not keep
connected nodes
addresses.
 It is installed at Data link
Layer.
 It has 4-24 ports.
 It may be_
 ACTIVE : HUB with
Repeater.

11. HUB

12. SWITCH
 Like a HUB Switch is also a central device
used in star networks.
 By default it unicast the message because it
keeps the address information of all the
connected devices but when broadcasting is
allowed it also broadcasts.
 It has 4-32 ports normally but also available in
128-256 ports.
 Modern Switches have inbuilt Repeaters.
 Installed at Layer2 or Layer 3 as required and
reads MAC addresses.

13. SWITCH

14. BRIDGE
 A device to connect two or more LANs.
 It may be_
 Transparent : connects homogeneous LANs.
 Translational : connects heterogeneous LANs.
 It keeps the information about configurations of
all the networks connected via Bridge; such as
topologies and access techniques.
 Installed at Data link layer.

15. BRIDGE

16. ROUTER
 A device that routes the signals
between the nodes from source to
destination between two or more
similar networks.
 It is installed at the network layer
and capable to read IP addresses
of the nodes.
 It also keeps the information about
the neighbour routers or nodes to
maintain the flow of forwarding the
data packets and therefore this
routers are known as mini
computers.

17. ROUTER
 Routers have
repeaters.
 Routers have inbuilt
firewall that filtrates
the unwanted
contents in the data
packets.
 Routing techniques
are helpful to select a
path for transmission.
 Virtual circuit
 Datagram approach

18. ROUTER
 Some devices are used as Bridge as well as
Routers called BROUTERS.
 At a time it works either as a Bridge or as a
Router.

19. GATEWAYS
 Gateway is a internetworking device.
 It is used to interconnect two dissimilar networks.
 It is installed at application layer in the network.
 Also known as protocol converter.

20. THE END