Exploration Network Chapter1 Shaw

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Centric World

2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1Version 4.0


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Objectives Describe how networks impact our daily lives.

Describe the role of data networking in the humannetwork.

en y e ey componen s o any a a ne wor .

Identify the opportunities and challenges posed by.

Describe the characteristics of network architectures:fault tolerance scalabilit ualit of service andsecurity.

2 2007 Cisco Systems, Inc. All rights reserved. Cisco Public


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How Networks Impact Daily Life The complex interconnection of electronic devices and

quality of life for people everywhere.



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New forms of

Instant messaging :: Realtime communicationbetween 2 or more eo lebased on typed text

Weblogs (Blogs) :: Web

pages created by an

Podcasting ::Website thatcontains audio files available

Wikis : : A collaboration tool.Gives people the opportunityto work together on shared


documents.


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Networks Supporting the Way We Learn

Using information networks to share andcollaborate improves teaching and learning

Courseware delivered over the datanetwork

Learn and share from anywhere, anytime



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Networks Supporting The Way We Work

Business networks

evolved to enable thetransmission of manyiff r n f

information services,

including e-mail, video,,telephony.

Resources can be

accessed and sharedremotely



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Reference/Notification



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Networks Supporting The Way We Play We compete with friends and foes around the world in



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Communications can take many forms and occurs in many

.

We establish rules, or protocols, for communicating with eachother:

Identify the sender and receiver.

Agree on the method.Common language.

Speed and delivery of the message.

Confirmation that the messa e was received.

Communications between individuals is successful if themeaning of the received message is the same as the meaning


of the message that was sent.


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Communications - Quality

For data networks, we use the same basic criteria to ud e

successful communication. However, there are external factors that can affect the

message.

The quality of the pathway between the sender and the recipient.

The number of times the message has to change form or beredirected or re-addressed.

The number of other messages being transmitted simultaneously onthe communication network.

The amount of time allotted for successful communication.



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Communications - Quality

Internal factors that interfere with network communication are

related to the nature of the message itself.

Internal factors affectin the successful communication across thenetwork include:

The size of the message Large messages may beinterru ted or dela ed at different oints within the network

The complexity of the message

The importance of the message A message with a low

overloaded.



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Communications - Quality There are also internal factors that can affect successful

.

Message SizeMessage

Complexity

MessageImportance



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Communications - Quality It is also more difficult to deliver a large, bulky package

smaller packages.



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Network As A Platform The role of data networking in communications

millions of messages beingexchanged between people allover the world

a web of interconnectednetworks

Man differentequipment/companies Standardization enablesequipment to work together



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Network As A Platform All networks have 4 basic elements in common:

.

Messages that travel from one device to another.

e um t at s use to nterconnect ev ces an cantransport the messages from one device to another.


.


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Network As A PlatformMessages take many forms.



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Network As A PlatformMedia on a network can be varied.



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Network As A PlatformDevices on a network Common Symbols



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Network As A PlatformRules on a network are many

Other Application Protocols: DNS, DHCP, FTP


TCP/IP Protocol Suite, Ethernet, Routing Protocols


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1. Converted to Binary.

2. NIC generates signals.

3. Passed among LAN devices.

. .



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The many interconnecteddevices worldwide are often

represented by a cloud.

5. Bits are transmitted todevices that interconnect


.


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6. Passed among localdevices at the destination.

7. The destination device converts



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u ng a oge er

At each of these steps, there areprotocols that define the rules for

55

ev ce commun cat on.

66 77

11 22 33 44



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Converged Networks Traditionally telephone, radio, television, and computer

of the four basic network elements.



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Converged Networks Technology advances are enabling us to consolidate these

.

A platform defined as a converged network.



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Converged Networks



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Network Architecture Characteristics

architecture designFault tolerance Packet Switching

Scalability

Quality of service (QoS)

u y



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Network Architecture Fault Tolerance



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Network Architecture Fault ToleranceCircuit Switched Connection-Oriented Networks



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Network Architecture Fault TolerancePacket Switched Connectionless Networks



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ir uit wit h P k t wit h

Connection-oriented Connectionless

Dedicated Circuit Shared Circuit

Guaranteed level of service

(Bandwidth, QoS)Messages divided into packets

Inefficient use of Medium Efficient use of Medium


Single path, no redundancyFault Tolerant, multiple possible

paths


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Network Architecture - Scalability



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Network Architecture - Scalability Characteristics of the Internet that help it scale to meet

HierarchicalCommon standards

Common protocols



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Network Architecture - Scalability A good example of scalability is the Tier architecture of the

.

Tier 2: Pay Tier 1 providers forTier 1: ISPs provide nationaland international connections.

connect v ty an prov eregional service.

(Verizon, Sprint, AT&T, NTT,cable systems, etc.)

InternetInternet

Tier 3: Provide service to endusers and are usually connected

ac oneac one .



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e wor rc ec ure - o



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Network Architecture - QoS



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Network Architecture - QoS



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Network Architecture - QoS The appropriate QoS strategy for a given type of traffic



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Network Architecture - ecurity



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Network Architecture - Security Networks must be secure



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Network Architecture - Security Basic measures to secure data networks

Ensure confidentiality through use of

User authentication

Maintain communication integrity through use of

Digital signaturesEnsure availability through use of

Firewalls

Hardware without a single point of failure



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e wor rc ec ure - ecur y

Strong authentication andappropriate encryption

Communication Integrity:

Digital Signatures, Hashinggor ms, ec sum

Ensuring Availability:

Combating virus attacks,Firewalls, RedundantArchitecture



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Summary


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Exploration Network Chapter1 Shaw