Transcript Lec1: Network Management (Review)

LEC1: NETWORK MANAGEMENT
(REVIEW)
Edited by:
Nada Alhirabi
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OUTLINE
What is the network?
Goals of the network
Network Classification
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By Distance
By resource access
By topology
By transmission medium
Rules for choosing the most suitable type of
network
Devices for Exchanging & Transferring Data
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Network Interface Card (NIC)
Modem
Hub
Repeater
Bridge
Router
Gateway
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WHAT IS THE NETWORK?
 Connecting two or more computing devices using
hardware and software to manage connection between
devices so that it is possible to:
 Share resources.
 Exchange information.
 Resources refers to: Hardware and software components
that is prepared to be used for networks. Such as:
1)
2)
3)
hardware(printer, hard disk, processor...etc),
software and systems (database management systems, extensive
programs)
Data (video, audio, voice, data,…etc)
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GOALS OF NETWORKS
1) Sharing different resources regardless of the distance.
2) Using secondary computers in the case of any failure or
malfunction.
3) Speeding up complicated operations such as: (math
applications,
simulation) by using multiple computers
and processors.
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REQUIREMENT FOR BUILDING A
NETWORK
1.
At least two computers
2.
Network Interface Card (NIC)
3.
Transmission media (wired or wireless)
4.
Switch, router or hub
5.
Application software:
1.
2.
3.
4.
Operating System.
Network operating system.
Network management system.
Network protocols.
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NETWORK CLASSIFICATION
1.
By Distance:
 Local Area Network (LAN)
 Metropolitan Area Networks (MAN)
 Wide Area Networks (WAN)
2.
By resource access:
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Peer-to-Peer network
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3.
4.
Server based network
By topology
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Bus
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Ring
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Star
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Mix
By transmission medium:
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Wired
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Wireless
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LOCAL AREA NETWORK (LAN)
Network computers are located relatively close to each other (few kilometers in
distance).
Limited to buildings owned by one organization.
Advantages:
 Efficiency & speed in data transmission.
 Less errors.
 LAN components are cheap & easily available.
Disadvantages:
 Difficulty to link different networks due to the large number of rules.
 Limitation in the geographic area.
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METROPOLITAN AREA NETWORK (MAN)
Used to cover medium size area around few kilometres) to link
computers in the same city such as universities.
Advantages:
 Fast & efficient in data transmission.
 Possibility to connect computers in one city.
Disadvantages:
 Rarely used.
 Difficulty in maintaining MAN due to its large size.
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WIDE AREA NETWORK (WAN)
Consist of group of LANs connected to each other to cover large
geographic area.
Advantages:
 Possibility to connect thousands of computers.
 Possibility to transfer large number of data.
 Possibility to connect different LANs owned by different organizations.
Disadvantages:
 Requires expensive hardware & software.
 Hard to operate
 Requires special kind of programs.
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CLASSIFYING NETWORK BY RESOURCE ACCESS
1. Peer to Peer (P2P) Networks
2. Client/Server Network
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PEER TO PEER (P2P) NETWORK
Peer-to-peer network architecture allows to connect two or
more computers in order to share their resources.
Example:
C
A
B
A->B: When A sends request to use B’s projector.
 A: the client
 B: the server
C->A: When C sends request to use A’s printer.
 C: the Client
 A: the server
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(P2P) ADVANTAGES & DISADVANTAGES
Advantages:
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Inexpensive.
Does not require additional program to manage he network.
Does not require high quality devices.
Easy to install & operate.
Disadvantages:
 Time & effort consumption due to the decentralized management.
 Not Secured.
 Poor Performance when number of users increase.
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(P2P) NETWORK MANAGEMENT
Every user in the P2P network is responsible for:
 Managing his own computer
 Obtaining which resources will be shared in the network
 Obtaining the sharing permission (read – write – read &write)
for the shared resources.
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CLIENT/SERVER NETWORKS
Client/Server Networks: a network in which one centralized,
powerful computer (called the server) is connected to many less
powerful personal computers or workstations (called clients).
Server: is a specially designed and very powerful computer
with large storage, fast processor & large memory.
Types of Servers:
 File Servers.
 Printer Servers.
 Application Servers.
 Communication Servers.
 Database Servers.
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CLIENT SERVER NETWORKS
A wants to use the printer
 A sends request to the server.
 Server responds by putting pc A in the
request queue.
 When it is A’s turn it uses the printer.
Server
C
C wants to use the database.
 C sends request to the server.
 Server responds by putting pc C in the
request queue.
 When it is C’s turn it uses the printer.
A
B
Request
Response
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ADVANTAGES OF CLIENT/SERVER NETWORKS
1.
Protecting data from loss and damage.
2.
Possibility to make scheduled backups.
3.
Possibility to increase number of users.
4.
The clients computers are inexpensive.
5.
Centralization of network resources in a single computer.
6.
Ease of data management and control.
7.
Highly secured.

Why? because the server allows only special persons to control the management of
network resources to issue permissions for users to use the resources that they need.
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DISADVANTAGES OF CLIENT SERVER NETWORKS
1.
Requires expensive programs.
2.
Requires powerful computer to be used as a server.
3.
Requires network management.
4.
When the server fails the entire network stops.
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CLIENT/SERVER NETWORK MANAGEMENT
Client Server networks are managed using
network management systems installed on the
server computer so that it controls everything
about the network including:
 The network performance
 Statistical reports
 Monitoring clients
 Monitoring resources.
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NETWORK CLASSIFICATION BASED ON ITS
TOPOGRAPHY
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BUS
Group of computer devices connected to each other along the
same backbone cable.
Advantages:
 Inexpensive.
 Doesn’t require a lot of devices to work.
 Easy to install and manage.
Disadvantages:
 When the backbone cable is broken the whole network stop.
 Increasing number of users in the network may lead to collisions.
 limited expansion
Ethernet example of a technology that uses bus topology.
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RING
A computer network where each computer & device are connected to each
other forming a large.
Data is sent around the ring until it reaches its final destination (Token Ring
Approach)
Advantages:
 Prevents data collisions.
 Guarantee data arrival.
 Give an equal chance of sending.
Disadvantages:
 If one of the connected devices fail the whole network stop.
 Very Slow.
Token Ring & FDDI are examples of technologies that uses ring topology
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STAR
Group of computer devices connected to each other with a central
device.
Advantages:
 Easy to install & maintain.
 Inexpensive.
 Uses twisted pair cables.
Disadvantages:
 If the central device fails the whole network stop.
Fast Ethernet is an example of a technology that uses star topology
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CLASSIFYING NETWORKS BASED ON
TRANSMISSION MEDIUM
Wired Networks
 Networks that use wires as a transmission medium for transferring data:
 Coaxial cables
 Twisted Cables
 Fiber Optic Cables.
Wireless Network
 Networks that uses the air as a transmission medium for transferring data.
 Radio signals
 Microwave signals
 Laser Signals
 Infrared signals.
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RULES FOR CHOOSING THE MOST
SUITABLE TYPE OF NETWORK
1.
2.
3.
4.
5.
Size of the organization.
Number of users in the network.
Level of security.
Type of the organization.
Level of management support required by the
organization.
6. Requirement for users of the network.
7. Budget for the network.
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DEVICES FOR EXCHANGING & TRANSFERRING
DATA
Network Interface Card (NIC)
Modem
Hub
 Passive hub
 Active hub
 Intelligence hub
Repeater
Bridge
Router
Gateway
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NETWORK INTERFACE CARD (NIC)
Network Interface Card (NIC): is a computer
circuit board or card that is installed in a
computer so that it can be connected to a network
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THE MODEM
MODEM: is a device that contains group of electronic circuits &
converts analog signals into digital signal & vice versa.
Types of MODEMS:
 Internal: Part of the motherboard.
 External: Device connected to the computer using a serial port.
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HUB
The most basic networking device that connects multiple computers or
other network devices together.
 Has no intelligence (No routing tables)
 Can detect collisions
 Hub works in the physical layer (1st layer) of the OSI model.
Hub has three basic types:
 Passive hub
 Active hub
 Intelligence hub
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HUB
Passive hub
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Does not regenerate signals
Does not strength signals
Simply retransmit signals
No electricity required
Active hub
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Regenerate , strength & retransmit the signals
Usually 8 - 12 Ports
Require electricity
Also Called ‘Multiport Repeaters’
Intelligence hub
 An active hub that have some network management capabilities.
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REPEATER
It is a device that amplify & regenerate & retransmit the signal over
the network.
Allows network expansion because it can increase number of connected
devices to the network.
Repeaters work on the physical layer (1st layer) of the OSI model.
Cannot be used with Ethernet or Token Ring
Benefits for using repeaters:
1.
2.
Strengthening & amplifying signals.
Expanding networks.
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BRIDGE
A device that is used to connect components & devices of the network.
Work on the Data link layer (2nd) of the OSI model.
Could be used to expand the size of LAN networks.
Have the ability to connect different types of cables (Twisted pair –
Coaxial - ...etc)
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ROUTER
A Router is a network device that forward packets from one network
to another.
It is a smart device that forwards packets based on:
 The current traffic conditions (load, line costs, bad lines, etc.).
 Internal routing tables (Intelligent )
Work on the Network layer (3nd) of the OSI model.
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DIFFERENT TYPES OF ROUTER
1. Static Router: requires from the network
administrator to install the routing table
manually.
2. Dynamic Router:
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Requires from the network administrator to install
the routing table manually at the beginning only.
After that the routing table is updated
automatically & the router chooses the best routing
path based on the routing protocol.
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GATEWAY
A network gateway is an internetworking system capable of joining together two
networks that use different base protocols.
A network gateway can be implemented depending on the types of protocols
they support in:
 Software
 Hardware
 Or a combination of both.
Network gateways can operate at any level of the OSI model.
Able to convert the data from one format to another and from one encoding
system to another
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