Transcript What is Network

Network Concepts
Outlines
• What is Network ?
• Types of Networks
• Network Topologies
• Some of Network Devices and cables
• What is protocol
• CCNA
What is Network ?
• Computer network : A collection of computing
devices that are connected in various ways in order to
communicate and share resources .
• Usually, the connections between computers in a
network are made using physical wires or cables
–
However, some connections are wireless, using radio
waves or infrared signals .
• The generic term node or host refers to any device
on a network
What is Network ? cont….
Gateway
Servers
Firewall
Switches
Clients
Types of Networks
Local Area
Network
(LAN)
Wide Area
Network
(WAN)
Types of Networks cont…
• Local Area Network (LAN) :
– A network that connects a relatively small number of machines in a
relatively close geographical area
• Wide Area Network (WAN) :
– A network that connects two or more local-area networks over a
potentially large geographic distance
LAN Network Topologies
Bus
Topology
Ring
Topology
Topologies
Star
Topology
LAN Network Topologies cont…
• Bus Topology:
– All nodes are connected to a single communication line that carries
messages in both directions
Disadvantages :
•
•
Adding more computers
will reduce the access
speed on the network.
•
Collations
CSMA/CD : Carrier Sense Multi Access / Collation Detection
Terminator
LAN Network Topologies cont…
• Ring Topology:
– A configuration that connects all nodes in a closed loop on which
messages travel in one direction
Token : In this topology, to
transmit on the wire your computer
must have control of the token or
wait for the token to be free
Disadvantages :
• that a single malfunctioning
workstation can disable the
whole network
LAN Network Topologies cont…
• Star Topology:
– A configuration that centers around one node to which all others
are connected and through which all messages are sent
Disadvantages :
• Expensive
• if a central device was to fail then all
computers connected to that device
would not be able to see the network
Network Devices
Network Devices
• What is a Hub?
– A hub is usually a small rectangular box, often made of plastic, which
receives its power from an ordinary wall outlet
– A hub joins multiple computers (or other network devices) together to
form a single network segment
– On this network segment, all computers can communicate directly with
each other
– Larger hubs contain 8, 12, 16, and even 24 ports
– Many times the last port is reserved for "uplink" which is the
connecting of one hub to another hub or similar device (joining two
segments together).
Network Devices cont….
• What is a Hub?
– Essentially, a hub simply receives incoming packets, possibly amplifies
the electrical signal, and broadcasts these packets out to all devices
on the network - including the one that originally sent the packet!
• a packet:
– is a formatted block of data carried by a computer network
• types of hubs :
Passive : do not amplify the electrical signal of incoming packets
Active : amplify the electrical signal of incoming packets back to
their original level
Intelligent: is typically stackable (built in such a way that multiple
units can be placed one on top of the other to conserve
space).
Network Devices cont….
• What is a Network Switch?
– A network switch is a small hardware device that joins multiple
computers together within one local area network (LAN)
– Unlike hubs, network switches are capable of inspecting data
packets as they are received, determining the source and
destination device of that packet, and forwarding it appropriately
– By delivering each message only to the connected device it was
intended for, a network switch conserves network bandwidth and
offers generally better performance than a hub
Network Devices cont….
• What is a Router?
– Routers are physical devices that join multiple wired or wireless
LAN networks together
– Technically, a wired or wireless router is a Layer 3 gateway device
• A Gateway:
– is a device that acts like a security guard and only allows data in or
out if it has the right network headers
Network Cables
What is protocol
• Protocols:
– are the rules governing the transfer of data information, it
can also be compared to how humans use languages (to get
your point across you must talk in the same language as the
person you are speaking to).
• Home “networkers” often use an Internet Protocol (IP) wired or
wireless for communication
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Course Information
CCNA Certification
Adaptive Testing
1 Paper
: 150 US $
Time Limit
: 90 minutes
No. Questions : 55 – 65
Passing Score : 849/1000
Questions Format :
1. Single Choice
2. Multiple Choice
3. Drag & Drop
4. Fill in the Blanks
5. Router Simulations
6. Scenario Based
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Reference Books
Reference Books
CCNA Routing and Switching
Study Guide by Todd
Lammle
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CCNA Course Overview
Day
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Day 5 :
Day 6
Day 7
Day 8
Day 9
Day 10
Day 11
Day 12
Day 13
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OSI Layers
IP Addressing & Subnetting
Subnetting, VLSM & CIDR
Initial Configuration &
Internal & External of Routers
Wan Interface Configuration &
Static & Default Routing
Dynamic Routing : RIP & IGRP
Dynamic Routing : OSPF & EIGRP
Access List - Standard, Extended & Named
Switching
VLAN – Virtual Lan
Integrated Service Digital Network
Frame- Relay
Troubleshooting of Leased Line
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Thank You
Questions ???