• Chapter 1 – Understanding Networks and their Building Blocks
    • 1-1 Introduction to Networks
    • 1-2 Networking Types
    • 1-3 OSI Reference Model
    • 1-4 TCP/IP Model
    • 1-5 Ethernet Technologies and Cabling
    • 1-6 Cisco 3 Layer Model
    • 1-7 Summary
  • Chapter 2 – IP Addressing and Subnets
    • 2-1 IP Addresses – Composition, Types and Classes
    • 2-2 Private and Public IP addresses
    • 2-3 Subnetting
    • 2-4 Variable Length Subnet Masks (VLSM)
    • 2-5 Route Summarization
    • 2-6 Troubleshooting IP Addressing
  • Chapter 3 Introduction to Cisco Routers, Switches and IOS
    • 3-1 Introduction to Cisco Routers, Switches, IOS & the Boot Process
    • 3-2 Using the Command-Line Interface (CLI)
    • 3-3 Basic Configuration of Router and Switches
    • 3-4 Configuring Router Interfaces
    • 3-5 Gathering Information and Verifying Configuration
    • 3-6 Configuring DNS & DHCP
    • 3-7 Saving, Erasing, Restoring and Backing up Configuration & IOS File
    • 3-8 Password Recovery on a Cisco Router
    • 3-9 Cisco Discovery Protocol (CDP)
    • 3-10 Using Telnet on IOS
    • 3-11 CCNA Lab #1
  • Chapter 4 Introduction to IP Routing
    • 4-1 Understanding IP Routing
    • 4-2 Static, Default and Dynamic Routing
    • 4-3 Administrative Distance and Routing Metrics
    • 4-4 Classes of Routing Protocols
    • 4-5 Routing Loops
    • 4-6 Route Redistribution
    • 4-7 Static and Default Route Lab
  • Chapter 5 Routing Protocols
    • 5-1 RIPv1 & RIPv2
    • 5-2 Configuring RIPv1 & RIPv2
    • 5-3 Verifying and Troubleshooting RIP
    • 5-4 Enhanced Interior Gateway Routing Protocol (EIGRP)
    • 5-5 Configuring EIGRP
    • 5-6 Verifying and Troubleshooting EIGRP
    • 5-7 Open Shortest Path First (OSPF)
    • 5-8 Configuring OSPF
    • 5-9 Verifying and Troubleshooting OSPF
    • 5-10 EIGRP and OSPF Summary & Redistribution Routes
    • 5-11 Lab 5-1: RIP
    • 5-12 Lab 5-2: EIGRP
    • 5-13 Lab 5-3: OSPF
  • Chapter 6 Switching and Spanning Tree Protocol
    • 6-1 Understanding Switching and Switches
    • 6-2 Initial Configuration of a Catalyst Switch
    • 6-3 Spanning Tree Protocol (STP)
    • 6-4 Cisco’s additions to STP (Portfast, BPDUGuard, BPDUFilter, UplinkFast, BackboneFast)
    • 6-5 Rapid Spanning Tree Protocol (RSTP) – 802.1w
    • 6-6 Per-VLAN Spanning Tree Plus (PVST+) and Per-VLAN RSTP (Rapid-PVST)
    • 6-7 EtherChannel
    • 6-8 Lab 6-1 – Port Security
    • 6-9 Lab 6-2 – STP
  • Chapter 7 VLANs and VTP
    • 7-1 MAC Address Table
    • 7-2 Virtual LANs (VLANs)
    • 7-3 Types of Switch Ports
    • 7-4 VLAN Trunking: ISL and 802.1Q
    • 7-5 VLAN Trunking Protocol (VTP)
    • 7-6 Inter-VLAN Routing
    • 7-7 VLAN Configuration
    • 7-8 Inter-VLAN Routing Configuration
    • 7-9 VTP Troubleshooting
    • 7-10 Voice VLAN Configuration
  • Chapter 8 – Network Security
    • 8-1 Network Security
    • 8-2 Cisco Firewalls
    • 8-3 Layer 2 Security
    • 8-4 AAA Security Services
    • 8-5 Secure Device Management
    • 8-6 Secure Communications
  • Chapter 9 – Access Lists
    • 9-1 Introduction to Access Lists
    • 9-2 Standard Access Lists
    • 9-3 Extended Access Lists
    • 9-4 Access Lists -Remote Access, Switch Port, Modifying & Helpful Hints
    • 9-5 Cisco Configuration Professional Initial Setup and Access List Lab
  • Chapter 10 – Network Address Translation (NAT)
    • 10-1 Introduction to NAT
    • 10-2 Static NAT Configuration & Verification
    • 10-3 Dynamic NAT Configuration
    • 10-4 NAT Overloading aka Port Address Translation (PAT)
    • 10-5 NAT Troubleshooting
    • 10-6 NAT Configuration with Cisco Configuration Professional
  • Chapter 11 – Wide Area Networks
    • 11-1 Introduction to Wide-Area Networks
    • 11-2 Point-to-Point WANs: Layer 1
    • 11-3 Point-to-Point WANs: Layer 2
    • 11-4 PPP Concepts
    • 11-5 PPP Configuration
    • 11-6 Troubleshooting Serial Links
    • 11-7 Frame Relay
    • 11-8 LMI and Encapsulation Types
    • 11-9 Frame Relay Congestion Control
    • 11-10 Frame Relay Encapsulation
    • 11-11 Frame Relay Addressing
    • 11-12 Frame-Relay Topology Approaches
    • 11-13 Frame Relay Configuration
    • 11-14 Other WAN Technologies
  • Chapter 12 – Virtual Private Networks
    • 12-1 VPN Concepts
    • 12-2 Types of VPN
    • 12-3 Encryption
    • 12-4 IPsec VPNs
    • 12-5 SSL VPNs & Tunneling Protocols
    • 12-6 GRE Tunnels
    • 12-7 VPN Summary
  • Chapter 13 – IPv6
    • 13-1 IPv6 Introduction
    • 13-2 IPv6 Address Configuration
    • 13-3 OSPF Version 3
    • 13-4 EIGRP for IPv6
    • 13-5 Summary
  • Chapter 14 – IP Services
    • 14-1 High Availability – VRRP, HSRP, GLBP
    • 14-2 Cisco IOS NetFlow
    • 14-3 Summary
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Networks Affect our Lives

In today’s world, through the use of networks, we are connected like never before. People with ideas
can communicate instantly with others to make those ideas a reality. The creation of online
communities for the exchange of ideas and information has the potential to increase productivity
opportunities across the globe. The creation of the cloud lets us store documents and pictures and
access them anywhere, anytime.

Network Components

All computers that are connected to a network and participate directly in network communication are
classified as hosts. Hosts can be called end devices. Some hosts are also called clients. Many
computers function as the servers and clients on the network. This type of network is called a peerto-peer network. An end device is either the source or destination of a message transmitted over the
network. Intermediary devices connect the individual end devices to the network and can connect
multiple individual networks to form an internetwork. Intermediary devices use the destination end
device address, in conjunction with information about the network interconnections, to determine the
path that messages should take through the network. The media provides the channel over which
the message travels from source to destination.

Network Representations and Topologies

Diagrams of networks often use symbols to represent the different devices and connections that
make up a network. A diagram provides an easy way to understand how devices connect in a large
network. This type of “picture” of a network is known as a topology diagram. Physical topology
diagrams illustrate the physical location of intermediary devices and cable installation. Logical
topology diagrams illustrate devices, ports, and the addressing scheme of the network.

Common Types of Networks

Small home networks connect a few computers to each other and to the internet. The small
office/home office (SOHO) network allows computers in a home office or a remote office to connect
to a corporate network, or access centralized, shared resources. Medium to large networks, such as
those used by corporations and schools, can have many locations with hundreds or thousands of
interconnected hosts. The internet is a network of networks that connects hundreds of millions of
computers world-wide. The two most common types of network infrastructures are Local Area
Networks (LANs), and Wide Area Networks (WANs). A LAN is a network infrastructure that spans a
small geographical area. A WAN is a network infrastructure that spans a wide geographical area.
Intranet refers to a private connection of LANs and WANs that belongs to an organization. An
organization may use an extranet to provide secure and safe access to individuals who work for a
different organization but require access to the organization’s data.

Internet Connections

SOHO internet connections include cable, DSL, Cellular, Satellite, and Dial-up telephone. Business
internet connections include Dedicated Leased Line, Metro Ethernet, Business DSL, and Satellite.
The choice of connection varies depending on geographical location and service provider
availability. Traditional separate networks used different technologies, rules, and standards.
Converged networks deliver data, voice, and video between many different types of devices over the
same network infrastructure. This network infrastructure uses the same set of rules, agreements,
and implementation standards. Packet Tracer is a flexible software program that lets you use
network representations and theories to build network models and explore relatively complex LANs
and WANs.

Reliable Networks

The term network architecture refers to the technologies that support the infrastructure and the
programmed services and rules, or protocols, that move data across the network. As networks
evolve, we have learned that there are four basic characteristics that network architects must
address to meet user expectations: Fault Tolerance, Scalability, Quality of Service (QoS), and
Security. A fault tolerant network is one that limits the number of affected devices during a failure.
Having multiple paths to a destination is known as redundancy. A scalable network expands quickly
to support new users and applications. Networks are scalable because the designers follow
accepted standards and protocols. QoS is a primary mechanism for managing congestion and
ensuring reliable delivery of content to all users. Network administrators must address two types of
network security concerns: network infrastructure security and information security. To achieve the
goals of network security, there are three primary requirements: Confidentiality, Integrity, and
Availability.

 Network Trends

There are several recent networking trends that affect organizations and consumers: Bring Your
Own Device (BYOD), online collaboration, video communications, and cloud computing. BYOD
means any device, with any ownership, used anywhere. Collaboration tools, like Cisco WebEx give
employees, students, teachers, customers, and partners a way to instantly connect, interact, and
achieve their objectives. Video is used for communications, collaboration, and entertainment. Video
calls are made to and from anyone with an internet connection, regardless of where they are
located. Cloud computing allows us to store personal files, even backup an entire drive on servers
over the internet. Applications such as word processing and photo editing can be accessed using the
cloud. There are four primary types of Clouds: Public Clouds, Private Clouds, Hybrid Clouds, and
Custom Clouds. Smart home technology is currently being developed for all rooms within a house.
Smart home technology will become more common as home networking and high-speed internet
technology expands. Using the same wiring that delivers electricity, powerline networking sends
information by sending data on certain frequencies. A Wireless Internet Service Provider (WISP) is
an ISP that connects subscribers to a designated access point or hot spot using similar wireless
technologies found in home wireless local area networks (WLANs).

Network Security

There are several common external threats to networks:
• Viruses, worms, and Trojan horses
• Spyware and adware
• Zero-day attacks
• Threat Actor attacks
• Denial of service attacks
• Data interception and theft
• Identity theft
These are the basic security components for a home or small office network:
• Antivirus and antispyware
• Firewall filtering
Larger networks and corporate networks use antivirus, antispyware, and firewall filtering, but they
also have other security requirements:
• Dedicated firewall systems
• Access control lists (ACL)
• Intrusion prevention systems (IPS)
• Virtual private networks (VPN)

Welcome to Introduction to Networks v7.0 (ITN)

 

First Time in This Course

A collage of images shaped into a long banner rectangle.

Welcome to the Introduction to Networks (ITN) course. This course introduces the architecture, structure, functions, components, and models of the Internet and other computer networks. The principles and structure of IP addressing and the fundamentals of Ethernet concepts, media, and operations are introduced to provide a foundation for the curriculum. By the end of the course, students will be able to build simple local area networks (LAN), perform basic configurations for routers and switches, and implement IP addressing schemes.

These course materials will assist you in developing the skills necessary to do the following:

  • Explain the advances in modern network technologies.
  • Implement initial settings including passwords, IP addressing, and default gateway parameters on a network switch and end devices.
  • Explain how network protocols enable devices to access local and remote network resources.
  • Explain how physical layer protocols, services, and network media support communications across data networks.
  • Calculate numbers between decimal, binary, and hexadecimal systems.
  • Explain how media access control in the data link layer supports communications across networks.
  • Explain how Ethernet operates in a switched network.
  • Explain how routers use network layer protocols and services to enable end-to-end connectivity.
  • Explain how ARP and ND enable communication on a local area network.
  • Implement initial settings on a router and end devices.
  • Calculate an IPv4 subnetting scheme to efficiently segment your network.
  • Implement an IPv6 addressing scheme.
  • Use various tools to test network connectivity.
  • Compare the operation of transport layer protocols in supporting end-to-end communication.
  • Explain the operation of the application layer in providing support to end-user applications.
  • Configure switches and routers with device hardening features to enhance security.
  • Troubleshoot connectivity in a small network.

Introduction to Networks

Networking Academy CCNAv7

Welcome to the first course of the Cisco Networking Academy CCNAv7 curriculum, Introduction to Networks (ITN). This is the first of three courses that are aligned to the CCNA Certification Exam. ITN contains 17 modules, each with a series of topics.

In Introduction to Networks, you will gain a basic understanding of the way networks operate. You will learn about network components and their functions, as well as how a network is structured, and the architectures used to create networks, including the internet.

But ITN is about more than learning networking concepts. By the end of this course, you will be able to build local area networks (LANs), configure basic settings on routers and switches, and implement internet protocol (IP).

In ITN, every concept that you learn and skill that you develop will be used in the rest of the CCNA curriculum. Now is the time to supercharge your networking career and let Cisco Networking Academy help you to reach your goal!

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Introduction

1.0.1

Why should I take this module?

Welcome to Networking Today!

Congratulations! This module starts you on your path to a successful career in Information Technology by giving you a foundational understanding of the creation, operation, and maintenance of networks. As a bonus, you get to dive into networking simulations using Packet Tracer. We promise you will really enjoy it!

1.0.2

What will I learn to do in this module?

Module Title: Networking Today

Module Objective: Explain the advances in modern network technologies.

Table caption
Topic TitleTopic Objective
Networks Affect our LivesExplain how networks affect our daily lives.
Network ComponentsExplain how host and network devices are used.
Network Representations and TopologiesExplain network representations and how they are used in network topologies.
Common Types of NetworksCompare the characteristics of common types of networks.
Internet ConnectionsExplain how LANs and WANs interconnect to the internet.
Reliable NetworksDescribe the four basic requirements of a reliable network.
Network TrendsExplain how trends such as BYOD, online collaboration, video, and cloud computing are changing the way we interact.
Network SecurityIdentify some basic security threats and solution for all networks.
The IT ProfessionalExplain employment opportunities in the networking field.

Networks Affect our Lives

1.1.1

Networks Connect Us

Among all of the essentials for human existence, the need to interact with others ranks just below our need to sustain life. Communication is almost as important to us as our reliance on air, water, food, and shelter.

In today’s world, through the use of networks, we are connected like never before. People with ideas can communicate instantly with others to make those ideas a reality. News events and discoveries are known worldwide in seconds. Individuals can even connect and play games with friends separated by oceans and continents.

1.1.2

Video - The Cisco Networking Academy Learning Experience

World changers aren’t born. They are made. Since 1997 Cisco Networking Academy has been working towards a single goal: the educating and skill building of the next generation of talent required for the digital economy.

1.1.3

No Boundaries

Advancements in networking technologies are perhaps the most significant changes in the world today. They are helping to create a world in which national borders, geographic distances, and physical limitations become less relevant, presenting ever-diminishing obstacles.

The internet has changed the manner in which our social, commercial, political, and personal interactions occur. The immediate nature of communications over the internet encourages the creation of global communities. Global communities allow for social interaction that is independent of location or time zone.

The creation of online communities for the exchange of ideas and information has the potential to increase productivity opportunities across the globe.

The creation of the cloud lets us store documents and pictures and access them anywhere, anytime. So whether we are on a train, in a park, or standing on top of a mountain, we can seamlessly access our data and applications on any device.

Network Components

1.2.1

Host Roles

If you want to be a part of a global online community, your computer, tablet, or smart phone must first be connected to a network. That network must be connected to the internet. This topic discusses the parts of a network. See if you recognize these components in your own home or school network!

All computers that are connected to a network and participate directly in network communication are classified as hosts. Hosts can be called end devices. Some hosts are also called clients. However, the term hosts specifically refers to devices on the network that are assigned a number for communication purposes. This number identifies the host within a particular network. This number is called the Internet Protocol (IP) address. An IP address identifies the host and the network to which the host is attached.

Servers are computers with software that allow them to provide information, like email or web pages, to other end devices on the network. Each service requires separate server software. For example, a server requires web server software in order to provide web services to the network. A computer with server software can provide services simultaneously to many different clients.

As mentioned before, clients are a type of host. Clients have software for requesting and displaying the information obtained from the server, as shown in the figure.

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An example of client software is a web browser, like Chrome or FireFox. A single computer can also run multiple types of client software. For example, a user can check email and view a web page while instant messaging and listening to an audio stream. The table lists three common types of server software.

TypeDescriptionEmailThe email server runs email server software. Clients use mail client software, such as Microsoft Outlook, to access email on the server. WebThe web server runs web server software. Clients use browser software, such as Windows Internet Explorer, to access web pages on the server.FileThe file server stores corporate and user files in a central location. The client devices access these files with client software such as the Windows File Explorer.
TypeDescription
EmailThe email server runs email server software. Clients use mail client software, such as Microsoft Outlook, to access email on the server.
WebThe web server runs web server software. Clients use browser software, such as Windows Internet Explorer, to access web pages on the server.
FileThe file server stores corporate and user files in a central location. The client devices access these files with client software such as the Windows File Explorer.

1.2.2

Peer-to-Peer

Client and server software usually run on separate computers, but it is also possible for one computer to be used for both roles at the same time. In small businesses and homes, many computers function as the servers and clients on the network. This type of network is called a peer-to-peer network.

In the figure, the print sharing PC has a Universal Serial Bus (USB) connection to the printer and a network connection, using a network interface card (NIC), to the file sharing PC.

1.2.3

End Devices

The network devices that people are most familiar with are end devices. To distinguish one end device from another, each end device on a network has an address. When an end device initiates communication, it uses the address of the destination end device to specify where to deliver the message.

An end device is either the source or destination of a message transmitted over the network.

Click Play in the figure to see an animation of data flowing through a network.

1.2.4

Intermediary Devices

Intermediary devices connect the individual end devices to the network. They can connect multiple individual networks to form an internetwork. These intermediary devices provide connectivity and ensure that data flows across the network.

Intermediary devices use the destination end device address, in conjunction with information about the network interconnections, to determine the path that messages should take through the network. Examples of the more common intermediary devices and a list of functions are shown in the figure.

1.2.5

Network Media

Communication transmits across a network on media. The media provides the channel over which the message travels from source to destination.

Modern networks primarily use three types of media to interconnect devices, as shown in the figure:

  • Metal wires within cables – Data is encoded into electrical impulses.
  • Glass or plastic fibers within cables (fiber-optic cable) – Data is encoded into pulses of light.
  • Wireless transmission – Data is encoded via modulation of specific frequencies of electromagnetic waves.

Different types of network media have different features and benefits. Not all types of network media have the same characteristics, nor are they appropriate for the same purposes.

Network Representations and Topologies

1.3.1

Network Representations

Network architects and administrators must be able to show what their networks will look like. They need to be able to easily see which components connect to other components, where they will be located, and how they will be connected. Diagrams of networks often use symbols, like those shown in the figure, to represent the different devices and connections that make up a network.

In addition to these representations, specialized terminology is used to describe how each of these devices and media connect to each other:

  • Network Interface Card (NIC) – A NIC physically connects the end device to the network.
  • Physical Port – A connector or outlet on a networking device where the media connects to an end device or another networking device.
  • Interface – Specialized ports on a networking device that connect to individual networks. Because routers connect networks, the ports on a router are referred to as network interfaces.

Note: The terms port and interface are often used interchangeably.

1.3.2

Topology Diagrams

Topology diagrams are mandatory documentation for anyone working with a network. They provide a visual map of how the network is connected. There are two types of topology diagrams: physical and logical.

Physical Topology Diagrams

Physical topology diagrams illustrate the physical location of intermediary devices and cable installation, as shown in the figure. You can see that the rooms in which these devices are located are labeled in this physical topology

Logical Topology Diagrams

Logical topology diagrams illustrate devices, ports, and the addressing scheme of the network, as shown in the figure. You can see which end devices are connected to which intermediary devices and what media is being used.

The topologies shown in the physical and logical diagrams are appropriate for your level of understanding at this point in the course. Search the internet for “network topology diagrams” to see some more complex examples. If you add the word “Cisco” to your search phrase, you will find many topologies using icons that are similar to what you have seen in these figures.

Common Types of Networks

1.4.1
Networks of Many Sizes

Now that you are familiar with the components that make up networks and their representations in physical and logical topologies, you are ready to learn about the many different types of networks.

Networks come in all sizes. They range from simple networks consisting of two computers, to networks connecting millions of devices.

Simple home networks let you share resources, such as printers, documents, pictures, and music, among a few local end devices.

Small office and home office (SOHO) networks allow people to work from home, or a remote office. Many self-employed workers use these types of networks to advertise and sell products, order supplies, and communicate with customers.

Businesses and large organizations use networks to provide consolidation, storage, and access to information on network servers. Networks provide email, instant messaging, and collaboration among employees. Many organizations use their network’s connection to the internet to provide products and services to customers.

The internet is the largest network in existence. In fact, the term internet means a “network of networks”. It is a collection of interconnected private and public networks.

In small businesses and homes, many computers function as both the servers and clients on the network. This type of network is called a peer-to-peer network.

1.4.2

LANs and WANs

Network infrastructures vary greatly in terms of:

  • Size of the area covered
  • Number of users connected
  • Number and types of services available
  • Area of responsibility

The two most common types of network infrastructures are Local Area Networks (LANs), and Wide Area Networks (WANs). A LAN is a network infrastructure that provides access to users and end devices in a small geographical area. A LAN is typically used in a department within an enterprise, a home, or a small business network. A WAN is a network infrastructure that provides access to other networks over a wide geographical area, which is typically owned and managed by a larger corporation or a telecommunications service provider. The figure shows LANs connected to a WAN.

LANs

A LAN is a network infrastructure that spans a small geographical area. LANs have specific characteristics:

  • LANs interconnect end devices in a limited area such as a home, school, office building, or campus.
  • A LAN is usually administered by a single organization or individual. Administrative control is enforced at the network level and governs the security and access control policies.
  • LANs provide high-speed bandwidth to internal end devices and intermediary devices, as shown in the figure.

WANs

The figure shows a WAN which interconnects two LANs. A WAN is a network infrastructure that spans a wide geographical area. WANs are typically managed by service providers (SPs) or Internet Service Providers (ISPs).

WANs have specific characteristics:

  • WANs interconnect LANs over wide geographical areas such as between cities, states, provinces, countries, or continents.
  • WANs are usually administered by multiple service providers.
  • WANs typically provide slower speed links between LANs.
1.4.3

The Internet

The internet is a worldwide collection of interconnected networks (internetworks, or internet for short). The figure shows one way to view the internet as a collection of interconnected LANs and WANs.

Some of the LAN examples are connected to each other through a WAN connection. WANs are then connected to each other. The red WAN connection lines represent all the varieties of ways we connect networks. WANs can connect through copper wires, fiber-optic cables, and wireless transmissions (not shown).

The internet is not owned by any individual or group. Ensuring effective communication across this diverse infrastructure requires the application of consistent and commonly recognized technologies and standards as well as the cooperation of many network administration agencies. There are organizations that were developed to help maintain the structure and standardization of internet protocols and processes. These organizations include the Internet Engineering Task Force (IETF), Internet Corporation for Assigned Names and Numbers (ICANN), and the Internet Architecture Board (IAB), plus many others.

 
1.4.4

Intranets and Extranets

There are two other terms which are similar to the term internet: intranet and extranet.

Intranet is a term often used to refer to a private connection of LANs and WANs that belongs to an organization. An intranet is designed to be accessible only by the organization’s members, employees, or others with authorization.

An organization may use an extranet to provide secure and safe access to individuals who work for a different organization but require access to the organization’s data. Here are some examples of extranets:

  • A company that is providing access to outside suppliers and contractors
  • A hospital that is providing a booking system to doctors so they can make appointments for their patients
  • A local office of education that is providing budget and personnel information to the schools in its district

The figure illustrates the levels of access that different groups have to a company intranet, a company extranet, and the internet.

Internet Connections

 
1.5.1

Internet Access Technologies

So, now you have a basic understanding of what makes up a network and the different types of networks. But, how do you actually connect users and organizations to the internet? As you may have guessed, there are many different ways to do this.

Home users, remote workers, and small offices typically require a connection to an ISP to access the internet. Connection options vary greatly between ISPs and geographical locations. However, popular choices include broadband cable, broadband digital subscriber line (DSL), wireless WANs, and mobile services.

Organizations usually need access to other corporate sites as well as the internet. Fast connections are required to support business services including IP phones, video conferencing, and data center storage. SPs offer business-class interconnections. Popular business-class services include business DSL, leased lines, and Metro Ethernet.

 
1.5.2

Home and Small Office Internet Connections

The figure illustrates common connection options for small office and home office users.

  • Cable – Typically offered by cable television service providers, the internet data signal transmits on the same cable that delivers cable television. It provides a high bandwidth, high availability, and an always-on connection to the internet.
  • DSL – Digital Subscriber Lines also provide high bandwidth, high availability, and an always-on connection to the internet. DSL runs over a telephone line. In general, small office and home office users connect using Asymmetrical DSL (ADSL), which means that the download speed is faster than the upload speed.
  • Cellular – Cellular internet access uses a cell phone network to connect. Wherever you can get a cellular signal, you can get cellular internet access. Performance is limited by the capabilities of the phone and the cell tower to which it is connected.
  • Satellite – The availability of satellite internet access is a benefit in those areas that would otherwise have no internet connectivity at all. Satellite dishes require a clear line of sight to the satellite.
  • Dial-up Telephone – An inexpensive option that uses any phone line and a modem. The low bandwidth provided by a dial-up modem connection is not sufficient for large data transfer, although it is useful for mobile access while traveling.

The choice of connection varies depending on geographical location and service provider availability.

 
1.5.3

Businesses Internet Connections

Corporate connection options differ from home user options. Businesses may require higher bandwidth, dedicated bandwidth, and managed services. Connection options that are available differ depending on the type of service providers located nearby.

The figure illustrates common connection options for businesses.

  • Dedicated Leased Line – Leased lines are reserved circuits within the service provider’s network that connect geographically separated offices for private voice and/or data networking. The circuits are rented at a monthly or yearly rate.
  • Metro Ethernet – This is sometimes known as Ethernet WAN. In this module, we will refer to it as Metro Ethernet. Metro ethernets extend LAN access technology into the WAN. Ethernet is a LAN technology you will learn about in a later module.
  • Business DSL – Business DSL is available in various formats. A popular choice is Symmetric Digital Subscriber Line (SDSL) which is similar to the consumer version of DSL but provides uploads and downloads at the same high speeds.
  • Satellite – Satellite service can provide a connection when a wired solution is not available.

The choice of connection varies depending on geographical location and service provider availability.

 
1.5.4

The Converging Network

Traditional Separate Networks

Consider a school built thirty years ago. Back then, some classrooms were cabled for the data network, telephone network, and video network for televisions. These separate networks could not communicate with each other. Each network used different technologies to carry the communication signal. Each network had its own set of rules and standards to ensure successful communication. Multiple services ran on multiple networks.

Converged Networks

Today, the separate data, telephone, and video networks converge. Unlike dedicated networks, converged networks are capable of delivering data, voice, and video between many different types of devices over the same network infrastructure. This network infrastructure uses the same set of rules, agreements, and implementation standards. Converged data networks carry multiple services on one network.

1.5.5

Video – Download and Install Packet Tracer

This video will show you how to download and install Packet Tracer. You will use Packet Tracer to simulate creating and testing networks on your computer. Packet Tracer is a fun, take-home, flexible software program that will give you the opportunity to use the network representations and theories that you have just learned to build network models and explore relatively complex LANs and WANs.

Students commonly use Packet Tracer to:

  • Prepare for a certification exam.
  • Practice what they learn in networking courses.
  • Sharpen their skills for a job interview.
  • Examine the impact of adding new technologies into existing network designs.
  • Build their skills for jobs in the Internet of Things.
  • Compete in Global Design Challenges (take a look at the 2017 PT 7 Design Challenge on Facebook).

Packet Tracer is an essential learning tool used in many Cisco Networking Academy courses.

To obtain and install your copy of Cisco Packet Tracer follow these steps:

Step 1. Log into your Cisco Networking Academy “I’m Learning” page.

Step 2. Select Resources.

Step 3. Select Download Packet Tracer.

Step 4. Select the version of Packet Tracer you require.

Step 5. Save the file to your computer.

Step 6. Launch the Packet Tracer install program.

Click Play in the video for a detailed walk-through of the Packet Tracer download and installation process.

1.5.6

Video – Getting Started in Cisco Packet Tracer

Packet Tracer is a tool that allows you to simulate real networks. It provides three main menus:

  • You can add devices and connect them via cables or wireless.
  • You can select, delete, inspect, label, and group components within your network.
  • You can manage your network by opening an existing/sample network, saving your current network, and modifying your user profile or preferences.

If you have used any program such as a word processor or spreadsheet, you are already familiar with the File menu commands located in the top menu bar. The Open, Save, Save As, and Exit commands work as they would for any program, but there are two commands that are special to Packet Tracer.

The Open Samples command will display a directory of prebuilt examples of features and configurations of various network and Internet of Things devices included within Packet Tracer.

The Exit and Logout command will remove the registration information for this copy of Packet Tracer and require the next user of this copy of Packet Tracer to do the login procedure again.

1.5.7

Packet Tracer – Network Representation

Reliable Networks

 
1.6.1

Network Architecture

Have you ever been busy working online, only to have “the internet go down”? As you know by now, the internet did not go down, you just lost your connection to it. It is very frustrating. With so many people in the world relying on network access to work and learn, it is imperative that networks are reliable. In this context, reliability means more than your connection to the internet. This topic focuses on the four aspects of network reliability.

The role of the network has changed from a data-only network to a system that enables the connections of people, devices, and information in a media-rich, converged network environment. For networks to function efficiently and grow in this type of environment, the network must be built upon a standard network architecture.

Networks also support a wide range of applications and services. They must operate over many different types of cables and devices, which make up the physical infrastructure. The term network architecture, in this context, refers to the technologies that support the infrastructure and the programmed services and rules, or protocols, that move data across the network.

As networks evolve, we have learned that there are four basic characteristics that network architects must address to meet user expectations:

  • Fault Tolerance
  • Scalability
  • Quality of Service (QoS)
  • Security
 
1.6.2

Fault Tolerance

A fault tolerant network is one that limits the number of affected devices during a failure. It is built to allow quick recovery when such a failure occurs. These networks depend on multiple paths between the source and destination of a message. If one path fails, the messages are instantly sent over a different link. Having multiple paths to a destination is known as redundancy.

Implementing a packet-switched network is one way that reliable networks provide redundancy. Packet switching splits traffic into packets that are routed over a shared network. A single message, such as an email or a video stream, is broken into multiple message blocks, called packets. Each packet has the necessary addressing information of the source and destination of the message. The routers within the network switch the packets based on the condition of the network at that moment. This means that all the packets in a single message could take very different paths to the same destination. In the figure, the user is unaware and unaffected by the router that is dynamically changing the route when a link fails.

1.6.3

Scalability

A scalable network expands quickly to support new users and applications. It does this without degrading the performance of services that are being accessed by existing users. The figure shows how a new network is easily added to an existing network. These networks are scalable because the designers follow accepted standards and protocols. This lets software and hardware vendors focus on improving products and services without having to design a new set of rules for operating within the network.

The network topology consists of four routers with redundant links including two connections to the Internet cloud. There are three LANs, one of which has been recently added. A text box reads: additional users and whole networks can be connected to the internet without degrading performance for existing users.

1.6.4

Quality of Service

Quality of Service (QoS) is an increasing requirement of networks today. New applications available to users over networks, such as voice and live video transmissions, create higher expectations for the quality of the delivered services. Have you ever tried to watch a video with constant breaks and pauses? As data, voice, and video content continue to converge onto the same network, QoS becomes a primary mechanism for managing congestion and ensuring reliable delivery of content to all users.

Congestion occurs when the demand for bandwidth exceeds the amount available. Network bandwidth is measured in the number of bits that can be transmitted in a single second, or bits per second (bps). When simultaneous communications are attempted across the network, the demand for network bandwidth can exceed its availability, creating network congestion.

When the volume of traffic is greater than what can be transported across the network, devices will hold the packets in memory until resources become available to transmit them. In the figure, one user is requesting a web page, and another is on a phone call. With a QoS policy in place, the router can manage the flow of data and voice traffic, giving priority to voice communications if the network experiences congestion.The focus of QoS is to prioritize time-sensitive traffic. The type of traffic, not the content of the traffic, is what is important.

network topology with PCs and IP phones connected to a switch which is connected to a router that is managing quality of service by prioritizing traffic

1.6.5

Network Security

The network infrastructure, services, and the data contained on network-attached devices are crucial personal and business assets. Network administrators must address two types of network security concerns: network infrastructure security and information security.

Securing the network infrastructure includes physically securing devices that provide network connectivity and preventing unauthorized access to the management software that resides on them, as shown in the figure.

Network administrators must also protect the information contained within the packets being transmitted over the network, and the information stored on network attached devices. In order to achieve the goals of network security, there are three primary requirements.

  • Confidentiality – Data confidentiality means that only the intended and authorized recipients can access and read data.
  • Integrity – Data integrity assures users that the information has not been altered in transmission, from origin to destination.
  • Availability – Data availability assures users of timely and reliable access to data services for authorized users.

Network Trends

 
1.7.1

Recent Trends

You know a lot about networks now, what they are made of, how they connect us, and what is needed to keep them reliable. But networks, like everything else, continue to change. There are a few trends in networking that you, as a NetAcad student, should know about.

As new technologies and end-user devices come to market, businesses and consumers must continue to adjust to this ever-changing environment. There are several networking trends that affect organizations and consumers:

  • Bring Your Own Device (BYOD)
  • Online collaboration
  • Video communications
  • Cloud Computing
 
1.7.2

Bring Your Own Device (BYOD)

The concept of any device, for any content, in any manner, is a major global trend that requires significant changes to the way we use devices and safely connect them to networks. This is called Bring Your Own Device (BYOD).

BYOD enables end users the freedom to use personal tools to access information and communicate across a business or campus network. With the growth of consumer devices, and the related drop in cost, employees and students may have advanced computing and networking devices for personal use. These include laptops, notebooks, tablets, smart phones, and e-readers. These may be purchased by the company or school, purchased by the individual, or both.

BYOD means any device, with any ownership, used anywhere.

Online Collaboration

Individuals want to connect to the network, not only for access to data applications, but also to collaborate with one another. Collaboration is defined as “the act of working with another or others on a joint project.” Collaboration tools, like Cisco WebEx, shown in the figure, give employees, students, teachers, customers, and partners a way to instantly connect, interact, and achieve their objectives.

Collaboration is a critical and strategic priority that organizations are using to remain competitive. Collaboration is also a priority in education. Students need to collaborate to assist each other in learning, to develop the team skills used in the workforce, and to work together on team-based projects.

Cisco Webex Teams is a multifunctional collaboration tool that lets you send instant messages to one or more people, post images, and post videos and links. Each team ‘space’ maintains a history of everything that is posted there.

1.7.4

Video Communications

Another facet of networking that is critical to the communication and collaboration effort is video. Video is used for communications, collaboration, and entertainment. Video calls are made to and from anyone with an internet connection, regardless of where they are located.

Video conferencing is a powerful tool for communicating with others, both locally and globally. Video is becoming a critical requirement for effective collaboration as organizations extend across geographic and cultural boundaries.

 
1.7.5

Video – Cisco Webex for Huddles

Click Play in the figure to view how Cisco Webex is incorporated into everyday life and business.

 

1.7.6

Cloud Computing

Cloud computing is one of the ways that we access and store data. Cloud computing allows us to store personal files, even backup an entire drive on servers over the internet. Applications such as word processing and photo editing can be accessed using the cloud.

For businesses, Cloud computing extends the capabilities of IT without requiring investment in new infrastructure, training new personnel, or licensing new software. These services are available on-demand and delivered economically to any device that is anywhere in the world without compromising security or function.

Cloud computing is possible because of data centers. Data centers are facilities used to house computer systems and associated components. A data center can occupy one room of a building, one or more floors, or an entire warehouse-sized building. Data centers are typically very expensive to build and maintain. For this reason, only large organizations use privately built data centers to house their data and provide services to users. Smaller organizations that cannot afford to maintain their own private data center can reduce the overall cost of ownership by leasing server and storage services from a larger data center organization in the cloud.

For security, reliability, and fault tolerance, cloud providers often store data in distributed data centers. Instead of storing all the data of a person or an organization in one data center, it is stored in multiple data centers in different locations.

There are four primary types of clouds: Public clouds, Private clouds, Hybrid clouds, and Community clouds, as shown in the table.

Cloud Types

Table caption
Cloud TypeDescription
Public cloudsCloud-based applications and services offered in a public cloud are made available to the general population. Services may be free or are offered on a pay-per-use model, such as paying for online storage. The public cloud uses the internet to provide services.
Private cloudsCloud-based applications and services offered in a private cloud are intended for a specific organization or entity, such as a government. A private cloud can be set up using the organization’s private network, though this can be expensive to build and maintain. A private cloud can also be managed by an outside organization with strict access security.
Hybrid cloudsA hybrid cloud is made up of two or more clouds (example: part private, part public), where each part remains a distinct object, but both are connected using a single architecture. Individuals on a hybrid cloud would be able to have degrees of access to various services based on user access rights.
Community cloudsA community cloud is created for exclusive use by specific entities or organizations. The differences between public clouds and community clouds are the functional needs that have been customized for the community. For example, healthcare organizations must remain compliant with policies and laws (e.g., HIPAA) that require special authentication and confidentiality. Community clouds are used by multiple organizations that have similar needs and concerns. Community clouds are similar to a public cloud environment, but with set levels of security, privacy, and even regulatory compliance of a private cloud.
 
1.7.7

Technology Trends in the Home

Networking trends are not only affecting the way we communicate at work and at school, but also changing many aspects of the home. The newest home trends include ‘smart home technology’.

Smart home technology integrates into every-day appliances, which can then connect with other devices to make the appliances more ‘smart’ or automated. For example, you could prepare food and place it in the oven for cooking prior to leaving the house for the day. You program your smart oven for the food you want it to cook. It would also be connected to your ‘calendar of events’ so that it could determine what time you should be available to eat and adjust start times and length of cooking accordingly. It could even adjust cooking times and temperatures based on changes in schedule. Additionally, a smart phone or tablet connection lets you connect to the oven directly, to make any desired adjustments. When the food is ready, the oven sends an alert message to you (or someone you specify) that the food is done and warming.

Smart home technology is currently being developed for all rooms within a house. Smart home technology will become more common as home networking and high-speed internet technology expands.

A depiction of smart home technology showing a cloud with arrows pointing to a house, a car, and a smartphone. Text at the bottom reads: The smart phone is updated from the cloud with the status of the smart home devices and the smart car; the user can then use the smart phone to interact with the smart home and smart car.

1.7.8

Powerline Networking

Powerline networking for home networks uses existing electrical wiring to connect devices, as shown in the figure.

Using a standard powerline adapter, devices can connect to the LAN wherever there is an electrical outlet. No data cables need to be installed, and there is little to no additional electricity used. Using the same wiring that delivers electricity, powerline networking sends information by sending data on certain frequencies.

Powerline networking is especially useful when wireless access points cannot reach all the devices in the home. Powerline networking is not a substitute for dedicated cabling in data networks. However, it is an alternative when data network cables or wireless communications are not possible or effective.

 
1.7.9

Wireless Broadband

In many areas where cable and DSL are not available, wireless may be used to connect to the internet.

Wireless Internet Service Provider

A Wireless Internet Service Provider (WISP) is an ISP that connects subscribers to a designated access point or hot spot using similar wireless technologies found in home wireless local area networks (WLANs). WISPs are more commonly found in rural environments where DSL or cable services are not available.

Although a separate transmission tower may be installed for the antenna, typically the antenna is attached to an existing elevated structure, such as a water tower or a radio tower. A small dish or antenna is installed on the subscriber’s roof in range of the WISP transmitter. The subscriber’s access unit is connected to the wired network inside the home. From the perspective of the home user, the setup is not much different than DSL or cable service. The main difference is that the connection from the home to the ISP is wireless instead of a physical cable.

Wireless Broadband Service

Another wireless solution for the home and small businesses is wireless broadband, as shown in the figure.

This solution uses the same cellular technology as a smart phone. An antenna is installed outside the house providing either wireless or wired connectivity for devices in the home. In many areas, home wireless broadband is competing directly with DSL and cable services.

Network Security

 
1.8.1

Security Threats

You have, no doubt, heard or read news stories about a company network being breached, giving threat actors access to the personal information of thousands of customers. For this reason, network security is always going to be a top priority of administrators.

Network security is an integral part of computer networking, regardless of whether the network is in a home with a single connection to the internet or is a corporation with thousands of users. Network security must consider the environment, as well as the tools and requirements of the network. It must be able to secure data while still allowing for the quality of service that users expect of the network.

Securing a network involves protocols, technologies, devices, tools, and techniques in order to protect data and mitigate threats. Threat vectors may be external or internal. Many external network security threats today originate from the internet.

There are several common external threats to networks:

  • Viruses, worms, and Trojan horses – These contain malicious software or code running on a user device.
  • Spyware and adware – These are types of software which are installed on a user’s device. The software then secretly collects information about the user.
  • Zero-day attacks – Also called zero-hour attacks, these occur on the first day that a vulnerability becomes known.
  • Threat actor attacks – A malicious person attacks user devices or network resources.
  • Denial of service attacks – These attacks slow or crash applications and processes on a network device.
  • Data interception and theft – This attack captures private information from an organization’s network.
  • Identity theft – This attack steals the login credentials of a user in order to access private data.

It is equally important to consider internal threats. There have been many studies that show that the most common data breaches happen because of internal users of the network. This can be attributed to lost or stolen devices, accidental misuse by employees, and in the business environment, even malicious employees. With the evolving BYOD strategies, corporate data is much more vulnerable. Therefore, when developing a security policy, it is important to address both external and internal security threats, as shown in the figure.

1.8.2

Security Solutions

No single solution can protect the network from the variety of threats that exist. For this reason, security should be implemented in multiple layers, using more than one security solution. If one security component fails to identify and protect the network, others may succeed.

A home network security implementation is usually rather basic. Typically, you implement it on the end devices, as well as at the point of connection to the internet, and can even rely on contracted services from the ISP.

These are the basic security components for a home or small office network:

  • Antivirus and antispyware – These applications help to protect end devices from becoming infected with malicious software.
  • Firewall filtering – Firewall filtering blocks unauthorized access into and out of the network. This may include a host-based firewall system that prevents unauthorized access to the end device, or a basic filtering service on the home router to prevent unauthorized access from the outside world into the network.

In contrast, the network security implementation for a corporate network usually consists of many components built into the network to monitor and filter traffic. Ideally, all components work together, which minimizes maintenance and improves security. Larger networks and corporate networks use antivirus, antispyware, and firewall filtering, but they also have other security requirements:

  • Dedicated firewall systems – These provide more advanced firewall capabilities that can filter large amounts of traffic with more granularity.
  • Access control lists (ACL) – These further filter access and traffic forwarding based on IP addresses and applications.
  • Intrusion prevention systems (IPS) – These identify fast-spreading threats, such as zero-day or zero-hour attacks.
  • Virtual private networks (VPN) – These provide secure access into an organization for remote workers.

Network security requirements must consider the environment, as well as the various applications, and computing requirements. Both home and business environments must be able to secure their data while still allowing for the quality of service that users expect of each technology. Additionally, the security solution implemented must be adaptable to the growing and changing trends of the network.

The study of network security threats and mitigation techniques starts with a clear understanding of the underlying switching and routing infrastructure used to organize network services.

The IT Professional

 
1.9.1

CCNA

As a NetAcad student, you may already have a career in IT, or are still educating yourself to prepare for your career. In either case, it is good to know about the skills needed to match the types of jobs that are available in IT.

The role and skills required of network engineers are evolving and are more vital than ever. The Cisco Certified Network Associate (CCNA) certification demonstrates that you have a knowledge of foundational technologies and ensures you stay relevant with skill sets needed for the adoption of next-generation technologies.

A consolidated and updated CCNA for networking engineers is three courses and one exam which covers the fundamental topics for all network technologies. The new CCNA focuses on IP foundation and security topics along with wireless, virtualization, automation, and network programmability.

There are new DevNet certifications at the associate, specialist and professional levels, to validate your software development skills.

There are specialist certification options to validate your skills in line with your job role and interests. This includes the Cisco Enterprise Advanced Infrastructure Specialist certification.

You can start where you want. There are no prerequisites to start earning your associate, specialist, professional, or expert level certification. Continuing education credits for recertification and ongoing development are now available for CCNA.

 
1.9.2

Networking Jobs

Your CCNA certification will prepare you for a variety of jobs in today’s market. At www.netacad.com you can click the Careers menu and then select Employment opportunities. You can find employment opportunities where you live by using the new program, the Talent Bridge Matching Engine. Search for jobs with Cisco, as well as Cisco partners and distributors seeking Cisco Networking Academy students and alumni.

You can also search for IT jobs using online search engines such as Indeed, Glassdoor, and Monster. Use search terms such as IT, network administrator, network architects, and computer systems administrator. You can also search using the term Cisco CCNA.

Module Practice and Quiz

 
1.10.1

What did I learn in this module?

Networks Affect our Lives

In today’s world, through the use of networks, we are connected like never before. People with ideas can communicate instantly with others to make those ideas a reality. The creation of online communities for the exchange of ideas and information has the potential to increase productivity opportunities across the globe. The creation of the cloud lets us store documents and pictures and access them anywhere, anytime.

Network Components

All computers that are connected to a network and participate directly in network communication are classified as hosts. Hosts can be called end devices. Some hosts are also called clients. Many computers function as the servers and clients on the network. This type of network is called a peer-to-peer network. An end device is either the source or destination of a message transmitted over the network. Intermediary devices connect the individual end devices to the network and can connect multiple individual networks to form an internetwork. Intermediary devices use the destination end device address, in conjunction with information about the network interconnections, to determine the path that messages should take through the network. The media provides the channel over which the message travels from source to destination.

Network Representations and Topologies

Diagrams of networks often use symbols to represent the different devices and connections that make up a network. A diagram provides an easy way to understand how devices connect in a large network. This type of “picture” of a network is known as a topology diagram. Physical topology diagrams illustrate the physical location of intermediary devices and cable installation. Logical topology diagrams illustrate devices, ports, and the addressing scheme of the network.

Common Types of Networks

Small home networks connect a few computers to each other and to the internet. The small office/home office (SOHO) network allows computers in a home office or a remote office to connect to a corporate network, or access centralized, shared resources. Medium to large networks, such as those used by corporations and schools, can have many locations with hundreds or thousands of interconnected hosts. The internet is a network of networks that connects hundreds of millions of computers world-wide. The two most common types of network infrastructures are Local Area Networks (LANs), and Wide Area Networks (WANs). A LAN is a network infrastructure that spans a small geographical area. A WAN is a network infrastructure that spans a wide geographical area. Intranet refers to a private connection of LANs and WANs that belongs to an organization. An organization may use an extranet to provide secure and safe access to individuals who work for a different organization but require access to the organization’s data.

Internet Connections

SOHO internet connections include cable, DSL, Cellular, Satellite, and Dial-up telephone. Business internet connections include Dedicated Leased Line, Metro Ethernet, Business DSL, and Satellite. The choice of connection varies depending on geographical location and service provider availability. Traditional separate networks used different technologies, rules, and standards. Converged networks deliver data, voice, and video between many different types of devices over the same network infrastructure. This network infrastructure uses the same set of rules, agreements, and implementation standards. Packet Tracer is a flexible software program that lets you use network representations and theories to build network models and explore relatively complex LANs and WANs.

Reliable Networks

The term network architecture refers to the technologies that support the infrastructure and the programmed services and rules, or protocols, that move data across the network. As networks evolve, we have learned that there are four basic characteristics that network architects must address to meet user expectations: Fault Tolerance, Scalability, Quality of Service (QoS), and Security. A fault tolerant network is one that limits the number of affected devices during a failure. Having multiple paths to a destination is known as redundancy. A scalable network expands quickly to support new users and applications. Networks are scalable because the designers follow accepted standards and protocols. QoS is a primary mechanism for managing congestion and ensuring reliable delivery of content to all users. Network administrators must address two types of network security concerns: network infrastructure security and information security. To achieve the goals of network security, there are three primary requirements: Confidentiality, Integrity, and Availability.

Network Trends

There are several recent networking trends that affect organizations and consumers: Bring Your Own Device (BYOD), online collaboration, video communications, and cloud computing. BYOD means any device, with any ownership, used anywhere. Collaboration tools, like Cisco WebEx give employees, students, teachers, customers, and partners a way to instantly connect, interact, and achieve their objectives. Video is used for communications, collaboration, and entertainment. Video calls are made to and from anyone with an internet connection, regardless of where they are located. Cloud computing allows us to store personal files, even backup an entire drive on servers over the internet. Applications such as word processing and photo editing can be accessed using the cloud. There are four primary types of Clouds: Public Clouds, Private Clouds, Hybrid Clouds, and Custom Clouds. Smart home technology is currently being developed for all rooms within a house. Smart home technology will become more common as home networking and high-speed internet technology expands. Using the same wiring that delivers electricity, powerline networking sends information by sending data on certain frequencies. A Wireless Internet Service Provider (WISP) is an ISP that connects subscribers to a designated access point or hot spot using similar wireless technologies found in home wireless local area networks (WLANs).

Network Security

There are several common external threats to networks:

  • Viruses, worms, and Trojan horses
  • Spyware and adware
  • Zero-day attacks
  • Threat Actor attacks
  • Denial of service attacks
  • Data interception and theft
  • Identity theft

These are the basic security components for a home or small office network:

  • Antivirus and antispyware
  • Firewall filtering

Larger networks and corporate networks use antivirus, antispyware, and firewall filtering, but they also have other security requirements:

  • Dedicated firewall systems
  • Access control lists (ACL)
  • Intrusion prevention systems (IPS)
  • Virtual private networks (VPN)

The IT Professional

The Cisco Certified Network Associate (CCNA) certification demonstrates that you have a knowledge of foundational technologies and ensures you stay relevant with skill sets needed for the adoption of next-generation technologies. Your CCNA certification will prepare you for a variety of jobs in today’s market. At www.netacad.com you can click the Careers menu and then select Employment opportunities. You can find employment opportunities where you live by using the Talent Bridge Matching Engine. Search for jobs with Cisco as well as Cisco partners and distributors seeking Cisco Networking Academy students and alumni.

Introduction

 
2.0.1

Why should I take this module?

Welcome to Basic Switch and End Device Configuration!

As part of your career in networking, you might have to set up a new network or maintain and upgrade an existing one. In either case, you’ll configure switches and end devices so that they are secure and perform effectively based on your requirements.

Out of the box, switches and end devices come with some general configuration. But for your particular network, switches and end devices require your specific information and instructions. In this module, you will learn how to access Cisco IOS network devices. You will learn basic configuration commands and use them to configure and verify a Cisco IOS device and an end device with an IP address.

Of course, there is much more to network administration, but none of that can happen without first configuring switches and end devices. Let’s get started!

 
2.0.2

What will I learn to do in this module?

Module Title: Basic Switch and End Device Configuration

Module Objective: Implement initial settings including passwords, IP addressing, and default gateway parameters on a network switch and end devices.

Table caption
Topic TitleTopic Objective
Cisco IOS AccessExplain how to access a Cisco IOS device for configuration purposes.
IOS NavigationExplain how to navigate Cisco IOS to configure network devices.
The Command StructureDescribe the command structure of Cisco IOS software.
Basic Device ConfigurationConfigure a Cisco IOS device using CLI.
Save ConfigurationsUse IOS commands to save the running configuration.
Ports and AddressesExplain how devices communicate across network media.
Configure IP AddressingConfigure a host device with an IP address.
Verify ConnectivityVerify connectivity between two end devices.

Cisco IOS Access

 
2.1.1

Operating Systems

All end devices and network devices require an operating system (OS). As shown in the figure, the portion of the OS that interacts directly with computer hardware is known as the kernel. The portion that interfaces with applications and the user is known as the shell. The user can interact with the shell using a command-line interface (CLI) or a graphical user interface (GUI).

When using a CLI, the user interacts directly with the system in a text-based environment by entering commands on the keyboard at a command prompt, as shown in the example. The system executes the command, often providing textual output. The CLI requires very little overhead to operate. However, it does require that the user have knowledge of the underlying command structure that controls the system.

analyst@secOps ~]$ ls
Desktop  Downloads  lab.support.files  second_drive
[analyst@secOps ~]$ 
 
2.1.2

GUI

A GUI such as Windows, macOS, Linux KDE, Apple iOS, or Android allows the user to interact with the system using an environment of graphical icons, menus, and windows. The GUI example in the figure is more user-friendly and requires less knowledge of the underlying command structure that controls the system. For this reason, most users rely on GUI environments.

  • Use a mouse to make selections and run programs
  • Enter text and text-based commands
  • View output on a monitor

A CLI-based network operating system (e.g., the Cisco IOS on a switch or router) enables a network technician to do the following:

  • Use a keyboard to run CLI-based network programs
  • Use a keyboard to enter text and text-based commands
  • View output on a monitor

Cisco networking devices run particular versions of the Cisco IOS. The IOS version is dependent on the type of device being used and the required features. While all devices come with a default IOS and feature set, it is possible to upgrade the IOS version or feature set to obtain additional capabilities.

The figure displays a list of IOS software releases for a Cisco Catalyst 2960 Switch.

Cisco Software Download Example

 
2.1.4

Access Methods

A switch will forward traffic by default and does not need to be explicitly configured to operate. For example, two configured hosts connected to the same new switch would be able to communicate.

Regardless of the default behavior of a new switch, all switches should be configured and secured.

Table caption
MethodDescription
ConsoleThis is a physical management port that provides out-of-band access to a Cisco device. Out-of-band access refers to access via a dedicated management channel that is used for device maintenance purposes only. The advantage of using a console port is that the device is accessible even if no networking services are configured, such as performing the initial configuration. A computer running terminal emulation software and a special console cable to connect to the device are required for a console connection.
Secure Shell (SSH)SSH is an in-band and recommended method for remotely establishing a secure CLI connection, through a virtual interface, over a network. Unlike a console connection, SSH connections require active networking services on the device, including an active interface configured with an address. Most versions of Cisco IOS include an SSH server and an SSH client that can be used to establish SSH sessions with other devices.
TelnetTelnet is an insecure, in-band method of remotely establishing a CLI session, through a virtual interface, over a network. Unlike SSH, Telnet does not provide a secure, encrypted connection and should only be used in a lab environment. User authentication, passwords, and commands are sent over the network in plaintext. The best practice is to use SSH instead of Telnet. Cisco IOS includes both a Telnet server and Telnet client.

Note: Some devices, such as routers, may also support a legacy auxiliary port that was used to establish a CLI session remotely over a telephone connection using a modem. Similar to a console connection, the AUX port is out-of-band and does not require networking services to be configured or available.

 
2.1.5

Terminal Emulation Programs

There are several terminal emulation programs you can use to connect to a networking device either by a serial connection over a console port, or by an SSH/Telnet connection. These programs allow you to enhance your productivity by adjusting window sizes, changing font sizes, and changing color schemes.

IOS Navigation

 
2.2.1

Primary Command Modes

In the previous topic, you learned that all network devices require an OS and that they can be configured using the CLI or a GUI. Using the CLI may provide the network administrator with more precise control and flexibility than using the GUI. This topic discusses using CLI to navigate the Cisco IOS.

As a security feature, the Cisco IOS software separates management access into the following two command modes:

  • User EXEC Mode – This mode has limited capabilities but is useful for basic operations. It allows only a limited number of basic monitoring commands but does not allow the execution of any commands that might change the configuration of the device. The user EXEC mode is identified by the CLI prompt that ends with the > symbol.
  • Privileged EXEC Mode – To execute configuration commands, a network administrator must access privileged EXEC mode. Higher configuration modes, like global configuration mode, can only be reached from privileged EXEC mode. The privileged EXEC mode can be identified by the prompt ending with the # symbol.

The table summarizes the two modes and displays the default CLI prompts of a Cisco switch and router.

Table caption
Command ModeDescriptionDefault Device Prompt
User Exec Mode
  • Mode allows access to only a limited number of basic monitoring commands.
  • It is often referred to as “view-only” mode.
Switch> 
Router>
Privileged EXEC Mode
  • Mode allows access to all commands and features.
  • The user can use any monitoring commands and execute configuration and management commands.
Switch# 
Router#
 
2.2.2

Configuration Mode and Subconfiguration Modes

To configure the device, the user must enter global configuration mode, which is commonly called global config mode.

From global config mode, CLI configuration changes are made that affect the operation of the device as a whole. Global configuration mode is identified by a prompt that ends with (config)# after the device name, such as Switch(config)#.

Global configuration mode is accessed before other specific configuration modes. From global config mode, the user can enter different subconfiguration modes. Each of these modes allows the configuration of a particular part or function of the IOS device. Two common subconfiguration modes include:

  • Line Configuration Mode – Used to configure console, SSH, Telnet, or AUX access.
  • Interface Configuration Mode – Used to configure a switch port or router network interface.

When the CLI is used, the mode is identified by the command-line prompt that is unique to that mode. By default, every prompt begins with the device name. Following the name, the remainder of the prompt indicates the mode. For example, the default prompt for line configuration mode is Switch(config-line)# and the default prompt for interface configuration mode is Switch(config-if)#.

2.2.4

Navigate Between IOS Modes

Various commands are used to move in and out of command prompts. To move from user EXEC mode to privileged EXEC mode, use the enable command. Use the disable privileged EXEC mode command to return to user EXEC mode.

Note: Privileged EXEC mode is sometimes called enable mode.

To move in and out of global configuration mode, use the configure terminal privileged EXEC mode command. To return to the privileged EXEC mode, enter the exit global config mode command.

There are many different subconfiguration modes. For example, to enter line subconfiguration mode, you use the line command followed by the management line type and number you wish to access. Use the exit command to exit a subconfiguration mode and return to global configuration mode.

Switch(config)# line console 0
Switch(config-line)# exit
Switch(config)#

To move from any subconfiguration mode of the global configuration mode to the mode one step above it in the hierarchy of modes, enter the exit command.

To move from any subconfiguration mode to the privileged EXEC mode, enter the end command or enter the key combination Ctrl+Z.

Switch(config-line)# end
Switch#

You can also move directly from one subconfiguration mode to another. Notice how after selecting an interface, the command prompt changes from (config-line)# para (config-if)#.

Switch(config-line)# interface FastEthernet 0/1
Switch(config-if)#
2.2.6

A Note About Syntax Checker Activities

When you are learning how to modify device configurations, you might want to start in a safe, non-production environment before trying it on real equipment. NetAcad gives you different simulation tools to help build your configuration and troubleshooting skills. Because these are simulation tools, they typically do not have all the functionality of real equipment. One such tool is the Syntax Checker. In each Syntax Checker, you are given a set of instructions to enter a specific set of commands. You cannot progress in Syntax Checker unless the exact and full command is entered as specified. More advanced simulation tools, such as Packet Tracer, let you enter abbreviated commands, much as you would do on real equipment.

 
2.2.7

Syntax Checker – Navigate Between IOS Modes

Use the Syntax Checker activity to navigate between IOS command lines on a switch.

Enter privileged EXEC mode using the enable command.

Switch>
 

The Command Structure

 
2.3.1

Basic IOS Command Structure

This topic covers the basic structure of commands for the Cisco IOS. A network administrator must know the basic IOS command structure to be able to use the CLI for device configuration.

A Cisco IOS device supports many commands. Each IOS command has a specific format, or syntax, and can only be executed in the appropriate mode. The general syntax for a command, shown in the figure, is the command followed by any appropriate keywords and arguments.

200-301 CCNA | CCNA Cisco Certified Network Associate CCNA Exam 2020