Data Networking
Fundamentals
Unit 7
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Objectives
Discuss basic networking concepts - elements common to clientserver
Provide examples of multiple network services
Describe differences between LANs, MANs, and WANs
Understand the function of each layer of the OSI model
Describe the purpose of protocols and recognize core protocols
and addressing scheme for the TCP/IP protocol suite
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Terminology
Standalone workstation - a workstation not connected to a network.
Relies on its own hard disk for data storage and applications. A
Personal computer (PC).
Client - a workstation or PC connected to a network. The person
whose workstation is part of a network may also be called a
“client”, or more informally a “user”.
Servers - store shared data and programs on their hard disks. They
perform management functions - such as determining a user’s
access to certain applications, data and services.
Client-server – an architecture that uses a server to enable clients
with sharing data storage space, networked devices and services.
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Terminology
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Requirements for Connectivity
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Requirements for Communications
Node - any device (a server, client, printer, mobile
device, etc.) that can receive messages across a
network. To receive data, each node must have a
unique address.
Protocol – a set of rules
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Servers
Server - A computer on the network that manages
shared resources.
Redundancy – Replica - Using more than one
component to guard against failure.
Network operating system (NOS) - software that can
manage data, users, groups, security, and
applications on the network.
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How Networks are Used
The purpose of using networks is to share services programs, data, and devices - known as resources.
Network services can be categorized as follows:
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File services
Print services
Communication services
Mail services
Internet services
Management services
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LANS, MANS, and WANS
Local area network (LAN) - a network of computers
and other devices that is limited to a relatively small
area, such as a building, rooms, or office.
Connectivity device - when multiple networks or
multiple parts of one network need to communicate
with each other, this device is used to exchange data
between them, ie hubs, routers and switches.
Hub – forward messages to all its connected devices.
Hubs today are Legacy replaced with switches.
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LANS, MANS, and WANS
Metropolitan area network (MAN) - a network that
connects LANs between multiple buildings in a region.
Wide area network (WAN) - a network that connects
geographically distinct LANs, MANs, CANs, PANs –
wired and/or wireless
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LANS, MANS, and WANS
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LANS, MANS, and WANS
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LANS, MANS, and WANS
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LANS, MANS, and WANS
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The Internet
The Internet is a unique WAN in size, and diversity. It is used to:
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Transmit confidential information between two offices or it may
transmit public information to anyone who requests it.
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Connect users from around the globe, the Internet relies on a
hierarchical structure of connection points, just as the PSTN relies
on a hierarchy of LEC and IXC switches.
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Connect to Internet Service Providers (ISP) – Companies that
operates a network and provides consumers links to the Internet.
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The Internet
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The Internet
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The OSI Model ( 7 layers)
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Application Layer
LAYER 7
Provides interfaces to software that enable
applications to use network services.
Application program interface (API) - A set of
instructions that allows a program to interact with an
operating system.
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Presentation Layer
LAYER 6
Establishes translation between the application and the
network.
Data becomes formatted in a schema that identifies the
application.
Encryption - A mathematical schema executed by both
the sender and receiver of the payload for security.
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Session Layer
LAYER 5
Functions include:
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Establishing and keeping alive the communications link for
the duration of the session
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Synchronizing the dialog between the two nodes
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Determining whether communications have been cut off and
establish where to restart transmission
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Transport Layer
LAYER 4
Responsible for ensuring that data is transferred from point A to
point B reliably, in the correct sequence, and without errors.
Handles flow control, a method of gauging the appropriate rate of
transmission.
Segmentation - the process “chunking up” the Payload when
moving data to the network layer into smaller units.
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Network Layer
LAYER 3
Translates network addresses into their physical
counterparts and decide how to route data from the
sender to the receiver.
Addressing is handled at the Network layer.
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Data Link Layer
LAYER 2
Controls communications between the Network layer
and the Physical layer.
Frame - a structured package for moving data that
includes not only data, or "payload," but also the
sender’s and receiver’s network addresses, and
error checking and control information.
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Data Link Layer
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Data Link Layer
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Physical Layer
LAYER 1
Generates and detects voltage (pulses of light) to transmit and
receive signals representing data.
Sets the data transmission rate and monitors data error rates.
Physical network problems, cut cable, disconnected cable,
improperly defined interface
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Applying the OSI Model
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Applying the OSI Model
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Applying the OSI Model
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TCP/IP Compared to the OSI
Model
The TCP/IP model includes the following:
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Layer 4 - Application layer - provides authentication and
compression services, and is roughly equivalent to the
Application, Presentation, and Session layers of the OSI model.
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Layer 3 - Transport layer - roughly corresponds to the
Transport layer of the OSI model.
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Layer 2 - Network layer - equivalent to the Network layer of
the OSI model.
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Layer 1 - Link layer - roughly equivalent to the Data Link and
Physical layers of the OSI model.
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The OSI and TCP/IP Models
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Internet Protocol
Belongs to the Network layer of the OSI model and to the Internet
layer of the TCP/IP model. It provides information about how
and where data should be delivered.
Datagram - the IP portion of a data frame, acts as an envelope for
data and contains information for routers to transmit data
between networks.
IP is an unreliable, connectionless protocol, which means that it
does not guarantee delivery of data.
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Internet Protocol
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Transmission Control Protocol (TCP)
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Transmission Control Protocol (TCP)
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The TCP/IP Application Layer
Protocols
Dynamic Host Configuration Protocol (DHCP) – automatically
assigns a unique Network layer (IP) address to devices that
access the network.
File Transfer Protocol (FTP) - sends and receive files between
hosts.
Hypertext Transfer Protocol (HTTP) - Enables Web browsers to
issue requests to Web servers and interpret the response.
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The TCP/IP Application Layer
Protocols
Simple Mail Transfer Protocol (SMTP) - Responsible for moving
messages from one mail server to another over the Internet.
Telnet - a terminal emulation protocol used to log on to remote
hosts to issue configuration instructions.
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Addressing in TCP/IP
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Addressing in TCP/IP
To view your current IP information on a Windows 2000-2008, XP,
Vista, 7 Windows XP Operating System:
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Click Start, then click Run. The Run dialog box opens.
In the Open text box, type cmd, then click OK. The Command
Prompt window opens.
At the DOS prompt, type ipconfig /all.Your workstation’s IP
address information is displayed
Type exit, then press Enter to close the Command Prompt
window.
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Addressing in TCP/IP
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Data Networks Summary
Workstations – client computers on a network share
data, programs, and devices through a central
computer called a server.
Servers - using a server to enable client computers to
share data storage space and devices constitutes a
client-server network.
Reference Models
OSI and TCP/IP
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The OSI and TCP/IP Models
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