- 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
- Online CCNA 200-301 Course in Quetta
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.
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.
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
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
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).
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)
First Time in This Course
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!
Online CCNA 200-301 Course in Pakistan
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!
What will I learn to do in this module?
What will I learn to do in this module?
Module Title: Networking Today
Module Objective: Explain the advances in modern network technologies.
|Topic Title||Topic Objective|
|Networks Affect our Lives||Explain how networks affect our daily lives.|
|Network Components||Explain how host and network devices are used.|
|Network Representations and Topologies||Explain network representations and how they are used in network topologies.|
|Common Types of Networks||Compare the characteristics of common types of networks.|
|Internet Connections||Explain how LANs and WANs interconnect to the internet.|
|Reliable Networks||Describe the four basic requirements of a reliable network.|
|Network Trends||Explain how trends such as BYOD, online collaboration, video, and cloud computing are changing the way we interact.|
|Network Security||Identify some basic security threats and solution for all networks.|
|The IT Professional||Explain employment opportunities in the networking field.|
Networks Affect our Lives
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.
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.
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.
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.
Online CCNA 200-301 Course in CCIE Academy
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.
|The email server runs email server software. Clients use mail client software, such as Microsoft Outlook, to access email on the server.|
|Web||The web server runs web server software. Clients use browser software, such as Windows Internet Explorer, to access web pages on the server.|
|File||The 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.|
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.
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.
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.
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
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.
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 NetworksNetworks of Many Sizes
Common Types of Networks
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.
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.
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.
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.
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.
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.
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.
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.
Packet Tracer – Network Representation
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.
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.
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.
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.
Powerline networking for home networks uses existing electrical wiring to connect devices, 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.
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
Module Practice and Quiz
Cisco IOS Access
- 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
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)#