Presentation on Networking devices which are used for communication.

1. Presentation on
Introduction to Networking
&
Network Devices

2. What is a Network?What is a Network?
A network consists of 2 or more computers connected
together, and they can communicate and share
resources (e.g. information)

3. Why Networking?Why Networking?
Sharing information — i.e. data communication
Do you prefer these?
• Or this?

4. HowHow many kinds of Networks?many kinds of Networks?
• Depending on one’s perspective, we can classify
networks in different ways
• Based on transmission media: Wired (UTP, coaxial
cables, fiber-optic cables) and Wireless
• Based on network size: LAN and WAN (and MAN)
• Based on management method: Peer-to-peer and
Client/Server
• Based on topology (connectivity): Bus, Star, Ring
…
:
:

5. Network DeviceNetwork Device
Hubs
Repeaters
Bridges
Switches
Routers
Gateways
MODEM

6. OSI ModelOSI Model

7. HUBHUB
Acts on the physical layer
Operate on bits rather than frames
Multiple Hubs can be used to extend the network
length
Regenerate the network’s signal and resend them to
other segments

8. Features & LimitationsFeatures & Limitations
 Features
• Can connect different types of media
• The most economic way of expanding networks
 Limitations
• Cannot join segments with
different access methods (e.g.
CSMA/CD and token passing)
• cannot filter network traffic
• cannot determine best path

9. RepeatersRepeaters
• Used to boost the signal between two cable segments
or wireless access points.
Repeaters clean, amplify, and resend signals that are
weakened by long cable length.
• Resides on Layer 1 of the OSI model.

10. BridgesBridges
• Connects two LANs and forwards or filters data
packets between them.
• Forward data depending on the Hardware (MAC)
address, not the Network address (IP).
• The purpose is to filter traffic on a LAN, to keep
local traffic local, yet allow connectivity to other
segments of the network.
• Resides on Layer 2 of the OSI model.

11. Differences Between Bridges andDifferences Between Bridges and
RepeatersRepeaters
Repeaters Bridges
OSI layer Physical layer Data link layer
Data
regeneration
Regenerate data at
the signal level
Regenerate data
at the packet
level
Reduce network
traffic
No Yes

12. SwitchesSwitches
Switches operate at the Data Link layer (layer 2) of the OSI
model
• Split large networks into small segments, decreasing the
number of users sharing the same network resources and
bandwidth.
Each channel has its own capacity and need not be shared
with other channels
10Mbps
10Mbps
10Mbps
Switch
Hub 3.3Mbps
3.3Mbps
3.3Mbps

13. RouterRouter
• Connects any number of LANs.
• Uses standardized protocols to move packets
efficiently to their destination.
• More sophisticated than bridges, connecting
networks of different types (for example, star and
token ring)
• Forwards data depending on the Network address
(IP), not the Hardware (MAC) address.
• Used routing tables to determine the best path for
data delivery

14. RouterRouter

15. GatewaysGateways
Joining together two networks that use different base
protocols.
Implemented completely in software, completely in
hardware, or as a combination of both.
Gateways operate at the any layer of the OSI model.
Also called protocol converters.

16. GatewaysGateways

17. MODEMMODEM

18. Devices and the layers at whichDevices and the layers at which
They operateThey operate
Layer Name of Layer Device
3 Network Routers, layer 3
switches
2 Data Link Switches,
bridges, NIC’s
1 Physical Hubs

19. SummarySummary
• Repeaters are the least expensive way to expand a
network, but they are limited to connecting two
segments
• Bridges function similar to repeaters, but can
understand the node addresses
• Switches can be considered as multiport bridges,
can divide a network into some logical channels
• Routers interconnect networks and provide
filtering functions. They can determine the best
route