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Welcome to, a free CCNA tutorial site where you can study CCNA

Welcome to website, a free CCNA tutorial site that closely follows the Cisco CCNA curriculum. The site was designed to help you pass the CCNA exam (640-802), but it can also be used as a reference site for anything networking related. Here you can find all materials needed to study for your CCNA exam.

On the left side you will find a list of articles. The articles on this site are divided by chapters. The first couple of chapters describe some basic networking terms and devices. The later chapters go a little bit in depth. You can start reading the articles from the beginning, or you can find a specific article that interest you.

So, what are you waiting for? Choose a topic on the left and start learning! We wish you luck!

This website is a part of the Geek University network, a free web portal covering many aspects of IT system administration.

Hope you’ll find this post informative.

peace and blessings,


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Computer Networks: Types of computer networks

The following is a sample chapter from the e-Book Computer Networks: An Introduction.  Enjoy reading!

Computer science is no more about computers than astronomy is about telescopes.” Edsger Dijkstra

It all started as a need to share resources! What existed as a concept and as an attempt to design the first computer network back in the 50’s, it was achieved in the ’60s by connecting some of the universities of that time. Over time, the desire to implement the first computer network as a result of curiosity had already been converted to a need that would fulfill the requirements. Precisely, it also led to the development and advancement of computer networking technologies. Thus, the need to connect and interconnect more computers into computer networks and with it more locations in itself resulted as the need to define topologies, architectures, technologies and computer networking categories. In that way, computer networks like personal area network (PAN), local area network (LAN), the metropolitan area network (MAN), and wide area network (WAN) were born.

Personal Area Network (PAN)

Back in time, in our society it wasn’t easy to own a home computer and that was mainly associated with material welfare since personal computers have been quite costly. In contrast, nowadays with the decrease of total cost of ownership of owning a computer have enabled many families to own a home computer. That said, as a result of a dynamic life and the need to communicate, besides home computer, households have printers, laptops, tablets, smartphones, and the Internet connection. Add to this the devices such as VoIP phone, smart TV, cable and satellite set-top box, surveillance cameras and other household devices with an interface to get connected into home computer network. Then all these connected devices in a computer network together with the media gateway, where usually are stored data files like audio and video, make up the personal area network (PAN). That said, PAN is defined as a computer network which is used to connect and transmit data among devices located in a personal area like home environment. Occasionally, from time to time, this computer network is often called home are network (HAN).


Figure 1. The personal area network (PAN)

Local Area Network (LAN)

Now that we know what a personal area network (PAN) is, it will help us to understand in a more clearly and the easiest way the local area network (LAN). In fact, looking from the physical and logical topology perspectives these computer networks hardly differ at all. So, the same is true for the communication technology (i.e. Ethernet or 802.3) that is utilized by both types of networks. Now this brings up the following question: if these networks are almost identical then why we have two definitions? As I mentioned at the beginning, for the sake of understanding the definition about local area network (LAN), the comparison with personal area network (PAN) will take place. When comparing the participating devices in these two computer networks, we find that the personal area network (PAN) is dominated by portable devices (i.e. mobile), while the local area network (LAN) mainly consists of fixed devices. Both computer networks are covering local area, however LAN has a greater coverage than PAN because LAN’s usually cover the floor of the building, several floors of the building, an entire building, or even few buildings which are close to one-another. Another difference is that PAN’s are mainly organized around an individual, while LAN’s are organized around the organization, business or legal entity. This then precisely defines the local area network (LAN) as the computer network where employees share network resources with one-another. In summary, the local area network (LAN) is a computer network that connects two or more computers in a local area for the purpose of sharing resources. Figure 2 shows an example of the local area network (LAN):


Figure 2. The local area network (LAN)

Metropolitan Area Network (MAN)

From the standpoint of coverage, the metropolitan area network (MAN) is greater than the local area network (LAN) and smaller than the wide area network (WAN). While from the viewpoint of data transmission speed, the metropolitan area network (MAN) is faster than the local area network (LAN) and the wide area network (WAN). As it was with PAN and LAN networks, the reason for the metropolitan area network (MAN) existence is the need for the allocation of resources in the city or metro. Therefore, the definition of metropolitan area network (MAN) is as follows:

  • a group of local area networks (LAN) connected within the geographical boundary of the town or city

The Figure 3 shows the metropolitan area network (MAN):


Figure 3. The metropolitan area network (MAN)

Wide Area Network (WAN)

Areas which are not covered by the local area network (LAN), or metropolitan area network (MAN) are covered by wide area network (WAN). That said, wide area network (WAN) is a computer network covering a wide geographic area using dedicated telecommunication lines such as telephone lines, leased lines, and satellites. So to say, while other computer networks have geographic restrictions of their physical reach, wide area network (WAN) has no geographical limitations. From this definition we understand that the composition of the wide area network (WAN) is made up of local personal area networks (PAN), local area networks (LAN), and the metropolitan area networks (MAN). With that in mind, the best example of the wide area network (WAN) is the Internet, which connects all computer networks mentioned in this chapter. The Figure 4 shows wide area network (WAN):


Figure 4. The wide area network (WAN)

In Conclusion

From the above definitions, you’ve learned about the characteristics of each of the types of computer networks. Although the differences may be significant both from the geographical scope and the communications technology, again the main element which brings these computer networks together is the very purpose of their existence. Therefore, as a reminder, the main purpose of computer networks existence is the resource sharing concept.

Take your time to share your experience with computer networks within Comment’s section. Thank you!

Hope you’ll find this post informative.

e-Book: Computer Networks – An Introduction

Whom this e-Book is for?

This e-Book is designed to provide you an introduction to computer networks. It contains the general concepts of the computer networks. That said, this e-Book is for everyone! It serves to beginners who are making the first steps in computer networks. At the same time, this e-Book can be used by intermediate and advanced users to bring back the computer network concepts. Other than that, this e-Book proves to be a handy informational source for everyone who is involved in studying computer networks in general, and computer networks concepts and definitions in particular. Moreover, the content on this e-Book is organized into chapters where each chapter covers a specific computer network topic. Each computer network topic is accompanied with an easy-to-understand explanations, self-descriptive graphics, and in conclusion sections. With the guidance provided by this easy to follow resource, you will quickly learn the general concepts and definitions of computer networks.

e-book-computer-networksComputer Networks: An Introduction (General Concepts)

Product Details:

  • File Size: 1322 KB
  • Simultaneous Device Usage: Unlimited
  • Publisher: Bekim Dauti; 1 edition (November 7, 2016)
  • Publication Date: November 7, 2016
  • Sold by: Amazon Digital Services LLC
  • Language: English

Table of Contents:

Chapter 1: What is a computer network?
Chapter 2: Types of computer networks
Chapter 3: Physical and logical topologies of computer networks
Chapter 4: Computer networks components
Chapter 5: Communications protocols in computer networks
Chapter 6: The OSI and TCP/IP reference models
Chapter 7: The IP addresses and subnets
Chapter 8: IPv6 vs IPv4
Chapter 9: The TCP’s reliable character
Chapter 10: The Internet’s big arena
Thank You!

Thank You!

Thank you for your time and consideration to download and read the e-Book! If you’ve liked this e-Book and want to participate actively in the further improvement process, then please e-Mail your:

  • comments
  • suggestions, and
  • observations

at With pleasure, I will read and try to include your comments, suggestions, and observation in the next editions of this e-Book.

Hope you’ll find this post informative.


What is a secure communication network?

“It is a fine thing to be honest, but it is also very important to be right.” Winston Churchill
(Guruge, 2003)


Secure communication network (Pixabay, 2016)

When wanting to provide security to a certain working environment, the first thing to be done is to evaluate what are the threats to such environment. Same applies to computer network security as well. Finding out which are the threats of your computer network and assessing its levels, increases the chances of choosing the best security solution which in turn facilitates its implementation. In order to deal with some thing appropriately, then it’s recommended to have adequate knowledge and experience of it. In this case, dealing with computer network security, one should have the knowledge of what is the computer network security and experience of implementing computer network security? According to the Webster dictionary, “security is defined as the condition or quality of being free from apprehension, anxiety, or care.” With this said, a “secure communication network can be defined as a network whose users do not feel any apprehension or anxiety while using the network” (Chandra, 2005, p. 1).

In real life, we notice different security technologies used and solutions implemented with a purpose to secure computer networks. But is the threat coming always from outside, or is more than that? Besides threats coming from outside of the perimeter network in organized way, “nearly half the security breaches comes from sources internal to an organization, and, in particular, employees” (Harrington, 2005, p. 3). Often we hear how a user mistakenly compromised the security of its corporate network, or a situation when the unknown flaws in certain application software caused to bring down several services inside of a perimeter network, or even shutting down the entire network. This means that humans and systems responsible for providing security to computer networks should always keep an eye open and be in a standby mode to secure a network against both external and internal intrusion attempts.


  1. Chandra, P. (2005).  Bulletproof Wireless Security GSM, UMTS, 802.11, and Ad Hoc Security.  Oxford, UK:  Elsevier, Inc.
  2. Guruge, A.  (2003).  Corporate Portals Empowered with XML and Web Services.  New York, NY:  Elsevier Science.
  3. Harrington, J. L.  (2005).  Network Security: A Practical Aproach.  San Francisco, CA: Elsevier, Inc.

Hope you’ll find this post informative.

peace and blessings,


Bekim Dauti’s Blog | Bekim Dauti’s Vlog | e-Books @Amazon Kindle Store

Simple Network Management Protocol (SNMP) vs. Common Management Information Protocol (CMIP)

“Why do you security people always speak of compromise as if it’s a bad thing? Good engineering is all about compromise.” – overheard at project review (Kaufman, Perlman, & Speciner, 2002, p.229)


Nowadays, when it comes to offering an efficient service on a computer network it’s all about network and system management. This represents the biggest challenge ever existed in Information and Communications Technology (ICT). That said, there are plenty of protocols, tools and systems offered for such purpose. With that in mind, in the following sections SNMP and CMIP are introduced and compared to one-another.


Computer Networking: A Top-Down Approach by Addison-Wesley (SlideShare, 2014)

Introduction to Simple Network Management Protocol (SNMP)

The Simple Network Management Protocol (SNMP) “was defined in the late 1980s to address the management needs of the evolving Internet” (Schönwälder, 2002, ¶ 1). The Internet Engineering Task Force (IETF) is responsible for defining the specifications and standards of SNMP.  It operates at application layer of the TCP/IP protocol suite by facilitating the process of management information exchange among devices in computer network. It’s a network management protocol used widely today by system/network administrators to: manage network performance, measure network performance, to locate problems in the network and solve same problems on those networks, to scale the network without downgrading services on the network, and other network management activities. Today exist three versions of SNMP: SNMPv1, SNMPv2 (enhancement of v1), and SNMPv3 (enhancements in security and privacy). According to Cisco (2012) “an SNMP-managed network consists of three components” (¶ 3):

• managed device – is a network node that contains an SNMP agent and that resides on a managed network
• agent – is a network-management software module that resides in a managed device
• network-management systems (NMSs) – executes applications that monitor and control managed devices

Introduction to Common Management Information Protocol (CMIP)

The Common Management Information Protocol (CMIP) “was developed and funded by government and corporations over a decade ago to replace and makeup for the deficiencies in SNMP” (Foreman et al., 1997, ¶ 1). The International Telecommunication Union is responsible for defining the specifications and standards of Telecommunications Management Network (TMN), which is based upon OSI CMIP specifications. CMIP “is the most comprehensive set of specifications and addresses all seven layers of the OSI Reference Model” (Subramanian, 2000, p. 103). CMIP it’s a network management protocol used widely by the people in charge within telecommunications networking environments to manage “telecommunication domains and telecommunication devices” (Foreman et al., 1997, ¶ 7). Based on how Foreman et al., (1997) had explained the CMIP structure, it consists of following components (¶ 2):

• managed object – is characteristics of a managed device that can be monitored, modified or controlled and can be used to perform tasks
• management agent – is sending the notifications and alarms to the network management application
• network management application – initiates transactions with management agent by using the following operations: action, cancel_get, create, delete, get, and set


According to Subramanian (2000) “the major advantages of SNMP over CMIP are” (p. 103-106) as follows:

• SNMP is truly simple, as it names indicates which makes it easy to implement thus resulting in most widely implemented network management system today
• SNMP based on scalar technology and simple definition of managed objects, is widely favored over CMIP
• SNMP takes less memory and processing’s resources from a device where it is accommodated in comparison to CMIP


According to Foreman et al., (1997) “the major advantages of CMIP over SNMP are” (¶ 5) as follows:

• CMIP variables not only relay information, but also can be used to perform tasks, which is impossible under SNMP.
• CMIP is a safer system as it has built in security that supports authorization, access control, and security logs.
• CMIP provides powerful capabilities that allow management applications to accomplish more with a single request.
• CMIP provides better reporting of unusual network conditions

In Conclusion

The fact that both SNMP and CMIP are not ideal products, since both contain issues when it comes to managing networking environments, then until the new better networking management protocol shows up on the horizon, currently by merging the good features form both SNMP and CMIP the existing networking management issues both in Internet and in Telecommunications can be surpassed. Such integration had been offered by Laraqui (2002) who proposes “a mechanism which will enable CMIP to be implemented directly on top of SNMP.” According to Laraqui (2002) the reason for such implementation is that “security and administrative mechanisms that are included in SNMPv2, or SNMPv1.5, can be reused for CMIP” This then will “enable Telecommunications operators to actively fight the network complexity inflation that is currently placing a heavy burden on Telecommunications networks” Laraqui (2002).


  1. Cisco Systems Inc. (2012, October 16).  Simple Network Management Protocol.  Retrieved November 02nd, 2016, from
  2. Kaufman, Ch., Perlman, R. & Speciner, Speciner.  (2002).  Network Security 2nd Ed. Upper Saddle River, NJ:  Prentice Hall 2002.
  3. Kim, L. (2002, October 15).  Integration of SNMP and CMIP.  Retrieved November 02nd, 2016, from
  4. Foreman, J. et al. (1997, June).  Software Technology Review.  Retrieved November 02nd, 2016, from
  5. Schönwälder, J. (2002, April 29).  Evolution of Open Source SNMP Tools.  Retrieved November 02nd, 2016 from
  6. Subramanian, M.  (2000).  Network Management: Principles and Practices.  Reading, MA: Addison Wesley.

Hope you’ll find this post informative.

peace and blessings,


Bekim Dauti’s Blog | Bekim Dauti’s Vlog | e-Books @Amazon Kindle Store