CCNA – Semester1

Chapter 1- Living in a Network Centric World

CCNA Exploration 4.0

Objectives

• Describe how networks impact our daily lives.

• Describe the role of data networking in the human network.

• Identify the key components of any data network.

• Identify the opportunities and challenges posed by

converged networks.

• Describe the characteristics of network architectures: fault-

tolerance, scalability, quality of service and security.

• Install and use IRC clients and a Wiki server.

Communication in a

Network-Centric World

How Networks Impact Daily Life

• Communication is almost as important to us as our reliance on air, water, food, and shelter.

• The communication method changes and evolves constantly.

• Early data network: limited to exchanging character-based information between connected computer systems.

• Current networks have evolved to carry voice, video streams, text, and graphics between many different types of devices.

How Networks Impact Daily Life

The way we live

How Networks Impact Daily Life

Some popular communication media:

• Instant messaging: Real time communication between 2 or more people based on typed text

• Weblogs (Blogs): Web pages created by an individual, easy to update and edit

• Wikis: Web pages created by anyone, likes weblogs but more public

• Podcasting: Website that contains audio files available for downloading

• Collaboration Tools: give people the opportunity to

work together on shared documents.

How Networks Impact Daily Life

The way we learn

• Communication, collaboration, and engagement are

fundamental building blocks of education. The learning

materials include interactive activities, assessments, and

feedback.

• Traditional learning methods: student can obtain

information only from the textbook and the instructor.

• E-learning courseware: contain voice, data, and video; any

time, anywhere; online discussion. Combine instructor-led

classes with online courseware.

• Access to high quality instruction.

• Removed geographic barriers

How Networks Impact Daily Life

• The Cisco Networking Academy Program is an example of a global online learning experience.

• Online courseware and delivery offer many benefits:

– Current and accurate training materials.

– Availability of training to a wide audience.

– Consistent quality of instruction.

– Cost reduction.

How Networks Impact Daily Life

The way we work

• Many different types of information services: e-mail, video,

messaging, and telephony.

• Intranets for private, extranets for suppliers, vendors, and

customers.

How Networks Impact Daily Life

The way we play

• Supported by services delivered by the data network

Communication –

An essential Part of Out Lives

Communication

• Basic characteristics of communication

– Rules or agreements are 1st established

– Important information may need to be repeated

– Various modes of communication may impact the

effectiveness of getting the message across.

Quality of Communications

• Communication is successful when the meaning of the message

understood by the recipient matches the meaning intended by the

sender.

• Many factors can prevent the message from reaching the recipient or

distort its intended meaning: external and internal.

External Factors

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

• The number of times the message has to change form

• The number of times the message has to be redirected or readdressed

• The number of other messages being transmitted simultaneously on

the communication network

• The amount of time allotted for successful communication

Internal Factors

• The size of the message

• The complexity of the message

• The importance of the message

Quality of Communications

The Network as a Platform

Data Networking Role

• Data or information networks: used for delivering of the

millions of messages; vary in size and capabilities, but have

four basic elements in common: Rules, The messages,

Medium, Devices

Data Networking Components

• Devices: these are used to communicate with one another

• Medium: this is how the devices are connected together

• Messages: information that travels over the medium

• Rules: governs how messages flow across network

The Elements of a Network

• Common devices:

– Switch

– Firewall

– Router

– Wireless Router

– Cloud

– Serial Link

The Elements of a Network

Network Connections

The Elements of a Network

• Human beings often seek to send and receive a variety of

message using computer applications; these applications

require services be provided by the network.

• Protocols are the rules that the networked devices use to

communicate with each other.

Sending an Instant Message: Example

Converged Networks

• Multiple networks:

each service has its

own individual

version of four basic

network elements

• Converged networks:

can carry voice, video

& data over the same

network

Converged Networks

• Intelligent Information Networks: offer so much more

than basic connectivity and access to applications.

• Planning for the Future

The Architecture of the Internet

Network Architecture Characteristics

• Network architecture: refers to both the technologies

that support the infrastructure and the programmed

services and protocols that move the messages

across that infrastructure. Four basic characteristics that

the underlying architectures need to address in order to

meet user expectations: fault tolerance, scalability,

quality of service, and security.

Four Characteristics

Fault Tolerant Network Architecture

• DoD (the United States Department of Defense): research a

communications medium that could withstand the destruction of

numerous sites and transmission facilities without disruption of

service fault tolerance.

• Circuit switched Connection-oriented Network: telephone systems

Fault Tolerant Network Architecture

• Packet Switched Connectionless Networks

Scalable Network Architecture

• The Internet: is able to expand, has a hierarchical layered

structure for addressing, for naming and for connectivity

services. Maintain peering relationships with other at the

same level.

Quality of service

Quality of service

• Quality of Service (QoS): to prioritize which types of data

packets must be delivered at the expense of other types of

packets that can be delayed or dropped. Two steps:

Classification and Assigning priorities

Quality of service

• Examples of priority decisions: time-sensitive; non time-

sensitive; high importance; undesirable communication.

Network Security

• The network infrastructure, services, and the data are crucial personal and business assets. Compromising the integrity of these assets could have serious business and financial repercussions.

• Consequences of a network security breach could include:

– Network outage that prevents communications and transactions occurring, with consequent loss of business

– Misdirection and loss of personal or business funds

– Company intellectual property (research ideas, patents or designs) that is stolen and used by a competitor

– Customer contract details that become known to competitors or made public, resulting in a loss of market confidence in the business

Network Security

Network Security

• Ensure confidentiality:

– User authentication

– Data encryption

• Maintain communication integrity:

– Digital signatures

• Ensure availability:

– Firewalls

– Redundant network architecture

– Hardware without a single point of failure

Trends in Networking

Trends in Networking

– Increasing number of mobile users

– Proliferation of network capable devices

– Expanding range of services

• There are three major trends that are contributing to the future shape of complex information networks:

Networking Career Opportunities

• Information Technology and networking careers are growing and

evolving as fast as the underlying technologies and services. As

networks increase in sophistication, the demand for people with

networking skills will continue to grow.

• Traditional IT positions like programmers, software engineers, data

base administrators and network technicians are now joined by new

titles, such as network architect, e-Commerce site designer,

information security officer, and home integration specialist.

Opportunities for forward thinking entrepreneurs are unlimited.

• Even non-IT jobs, like manufacturing management or medical

equipment design, now require a significant amount of knowledge

about network operation in order to be successful.

• Chief Technology Officers in many large organizations list the lack of

qualified personnel as the primary factor delaying the implementation

of innovative new services.

Summary