Computer Network Tutorial

Introduction of Computer Network Types of Computer Network Network Topology Computer Networking Architecture Transmission Modes (Data Flow) Basic Networking Devices Integrate Services Digital Network (ISDN)


OSI Model TCP/IP Model

Physical Layer

Digital Transmission Analog Transmission Transmission Media Switching

Data Link Layer

Error detection and Error correction Data Link Control Multiple Access Aloha

Network Layer

Network Layer - Logical Address Address Mapping Unicast Routing Protocol

Transport Layer

Process to Process Delivery User Datagram Protocol Transmission Control Protocol Stream Control Transmission Protocol Session Layer and Presentation Layer

Application Layer

Domain Name System Application Protocol E-mail Cryptography


Classes of Routing Protocols Classification of Routing Algorithms Controlled Access Protocols in Computer Networks Differences between IPv4 and IPv6 Fixed and Flooding Routing Algorithms Advantages and Disadvantages of Fibre Optics Cable APIPA Difference between Active and Passive FTP Fiber Optics and its Types Method of Joining and Fusion of Fiber Optic Cable Define Framing in Computer Network Disadvantages of Computer Network Mesh Topology Diagram in Computer Network Ring Topology in Computer Network Star Topology in Computer Networks 4G Mobile Communication Technology Advantages and Disadvantages of LAN Advantages and Disadvantages of MAN Advantages and Disadvantages of WAN Application Layer in OSI Model Cyclic Redundancy Check Example Data link layer in OSI model Difference between Transport and Network Layer Hamming Code Example Network Layer in OSI Model Session Layer in OSI Model Transport Layer in OSI Model Two Port Network in Computer Networks Uses of Computer Networks What is Computer Network What is Framing in a Computer Network Advantages and Disadvantages of Bus Topology Difference between Star Topology and Bus Topology Subnetting in Computer Network Subnetting Questions and Answers What is Bus Topology What is Network Topology and Types in Computer Networks Access Control in Networking Basic Characteristics of Computer Network Benefits of SOCKS5 Proxy in Computer Networks Computer Network viva Questions Difference between BOOTP and RARP Difference Between Network Topologies and Network Protocols Difference between NFC and RFID Difference Between Point-to-Point Link and star Topology Network Differences Between MSS and MTU Differences Between Trunk Port and Access Port Different Modes of Communication in Computer Networks MIME Protocol in Computer Networks Modes of Communication in Computer Networks Network Attack in Computer Network Port Address in Networking Simplest Protocol in Computer Network Sliding Window Protocol in Computer Network Stop And Wait Protocol in Computer Networks TCP 3-Way Handshake Process in Computer Networks What is a Proxy Server What is APPN What is ICMP Protocol What is Point-to-Point Protocol What is Port Address in Networking What is the HDLC Protocol What is VRRP Protocol Difference Between Analog and Digital Signals Difference Between Hub and Repeater Difference between Repeater and Switch Difference Between Transparent Bridge and Source Routing Bridge Source Routing Bridge in Computer Networks Transparent Bridge in Computer Networks Transport Protocol in Computer Networks Types of CSMA in Computer Networks What is Wired and Wireless Networking Network Security in Computer Network Disadvantages of Extranet Difference Between TELNET and FTP Define Protocol in Computer Networks Guided Transmission Media in Computer Network What is a Gateway in a Computer Network IGMP in Computer Networks LAN Protocols in Computer Networks MAN Meaning in Computer Modulation Techniques in Computer Networks Switching in DCN TCP/IP Applications What is IGMP? What is Modem in Networking What is Non-Persistent CSMA Difference between Cell Splitting and Cell Sectoring Forouzen Computer Network Open Loop and Closed Loop Congestion Control Types of Cluster Computing WAP-Wireless Access Point What are the elements of the Transport Protocol Difference between Gateway and Switch Flow Control in Data Link Layer Body Area Network Flooding in Computer Network Token Ring in Computer Networks VoIP in Computer Networks What is Infrared Transmission Congestion Control Techniques Forward Error Correction (FEC) Switching Techniques What is Telnet in Computer Network What are the Types of IPv4 Addresses IEEE 802.6 (DQDB) IEEE 802.15.4 Technology What is HDLC (High-level Data Link Control)? What is SMS Hubbing in Telecom? Circuit Switching in Computer Networks Communication Satellites in Computer Networks Features of HTTP Protocol IMAP4 (Internet Message Access Protocol) Internet Services How to Set up a Wireless Router Internetwork Routing in Computer Networks Distributed Computing System Features of GSM The 802.11 MAC Sublayer Protocol What is IEEE 802.3? What are Hubs and Switches in Computer Networks? What is Modem in a Computer Network? What is multicasting in Computer Networks? GSM -The Mobile Station What is Network Server? Slotted Aloha in Computer Network What is Ethernet in Computer Networks What is Arpanet? Radio Access Network (RAN) TCP 3-Way Handshake Process PING SWEEP (ICMP SWEEP) Print Server Private IP Address Security Services in Computer Networks Protocol Data Unit (PDU) CSMA with Collision Avoidance (CSMA/CA) What is Gateway in Computer Network? Advantages of Networking Data Link Layer Design Issues DHCP in Computer Networks Internet Security Association and Key Management Protocol (ISAKMP) What is Switch Hub? Telnet Full form in Networking Multimedia Systems Quality of Service in Computer Networks What is Carrier Sense Multiple Access (CSMA)? What is Circuit Switching What is Duplex Network? What is Web Protocol Network LAN Technologies Classes in Computer Network Low-Density Parity Check (LDPC) Wireless Internet Service Providers(Wisps) What is Handshaking? Cache Server What Is WSN Network? Check Sum Error Detection Linear Bus Topology Functions of the Transport Layer Infrared Transmission in Computer Networks Digital Signal in Computer Network Digital Data Transmission in Computer Networks Define Checksum with Example Computer Network Security Requirements Brust Errors in Computer Network Back Side Bus (BSB) 2-Dimension Parity Check in Computer Network Router and Brouter Microwave Transmission in Computer Networks Magnetic Media in Computer Network A One-Bit Sliding Window Protocol CDMA-Near-Far Problem Reference Models in Computer Networks Uni-cast, Broadcast, and Multicast in Computer Networks Uses Of Bridges in Computer Networks What are Gateways in Computer Network?

Security Services in Computer Networks

Computer network security refers to steps used by businesses or organizations to detect and prevent illegal access from external adversaries.

The needs for different methods to computer management of network security vary according on the scope of a computer network. As an instance, an office at home requires simple network security, but major organizations require extensive maintenance to protect the network from unwanted assaults.

Security Services in Computer Networks

The network administrator has control over who has access to the network's data and software. The username and password are assigned by the network administrator to the authorized individual.

What are Security Services?

X.800 describes a security service that is supplied by the protocol layer of interacting open systems and assures acceptable system or data transfer security. RFC 2828 defines security services as a system-provided processing or communication channel that protects system resources through security policies and mechanisms.

X.800 categorizes these offerings into five groups and fourteen distinct. We examine every group in turn.


The authentication service is responsible for ensuring that the interaction is legitimate. In the event of just one message, such as an alert or alarm signal, the authentication service's job is to ensure that the message comes from the source that it purports to originate from. In the event of a continuing contact, such as connecting the terminal to the host, two components are engaged. First, upon connection commencement, the service ensures that both entities are authentic, that is, each of them is who it claims to be. Secondly, the service must ensure that the link is not disrupted in such a manner that someone else may impersonate one of the two lawful parties in the event of illegal transmission or reception.

X.800 defines two particular authentication services:

  • Peer entity authentication: It allows for the verification of the identification of a peer entity within an association. Peers are two entities that implement the same protocol in distinct systems; for example, two TCP modules in two cooperating systems. Peer authentication for entities is used to establish a connection, as well as throughout the data transfer phase. It seeks to instil trust that a company is not engaging in a disguise or an illegal repeat of a prior connection.
  • Data origin authentication: It confirms the origin of a data unit. It does not safeguard data units against duplicate or alteration. This sort of service is suitable for applications such as electronic mail that require no prior contacts between the communicating entities.

Access Control

In the setting of network safety, access control refers to the capacity to restrict and control access to host applications and systems via communication channels. To do this, any entity attempting to get access needs to first recognized, or authenticated, in order to access privileges may be customized for the individual.

Data confidentiality

Confidentiality refers to the safeguarding of communicated data from passive assaults. There are different layers of security available depending on the content of the data transfer. The most comprehensive solution safeguards all user data exchanged between both parties during a period of period. For instance, when a Transmission Control Protocol (TCP) connection is established between two computers, this wide protection forbids the release if any user data transferred via the TCP connection. The service may additionally be defined in more particular terms, such as protecting just one message or specific fields inside a message. These adjustments are less helpful than the overall method and may be more difficult and costly to execute.

The other part of secrecy is to prevent traffic flow from analysis.

This demands that an attacker be unable to see the point of origin and destination, frequency, duration, or other properties of transmission on a communication facility

  • Connection confidentiality is the safeguarding of all user data across a connection.
  • Connectionless Confidentiality protects all personal information in a single data block.
  • Selective-Field Confidentiality refers to the privacy of specific fields within a user's data, whether on a network or in a single block.
  • Traffic Flow Confidentiality refers to the security of information derived from traffic flow observations.

Data Integrity

As with privacy, integrity can refer to a series of communications, just one message, or certain fields inside a message. Again, the most practical and simple method is entire stream protection.A focused on connections integrity service, which deals with a continuous flow of messages, ensures that communications are received exactly as they were sent, with no duplicate, insertion, alteration, reordering, or replay. Data deletion is also covered by this service. Thus, a connection-based integrity service handles both message stream modifications and denial of service. A connectionless integrity service, on the other hand, deals with specific messages without respect for any wider context and often just protects against message tampering.

We may distinguish between services with or without recovery. Because the reliability of service pertains to current assaults, we are more concerned with detection than prevention. If an integrity violation is identified, the service may merely notify it, and recovery from the violation will require the involvement of another piece of software or humans. Alternatively, there are ways for recovering from data integrity loss, which we shall discuss later. In most cases, including automatic recovery techniques is a better option.

  • Connection Integrity including Recovery ensures the authenticity of every user's information on a connection and identifies any modifications, insertions, deletions, or replays inside a data sequence, including recovery attempts.
  • Connection Integrity without Recovery: Same as before, but merely detects and does not recover.
  • Selective-Field Connection Integrity ensures the integrity of specified fields in user data when sent across a connection. This includes determining if the fields have been edited, inserted, removed, or replayed.
  • Connectionless Integrity ensures the accuracy of a single data block by detecting any modifications. Additionally, rudimentary replay detection may be available.
  • Selective-Field Connectionless Integrity ensures the integrity of specified fields in a single connectionless data block by determining if they have been updated.


Nonrepudiation forbids either the sender or the receiver from refuting a conveyed message. As a result, when a communication is transmitted, the recipient can show that the supposed sender actually sent it. Similarly, when a communication is received, its sender can demonstrate that the supposed receiver actually got the message.

  • Nonrepudiation and origin: Confirmation that the communication was transmitted by the designated party.
  • Nonrepudiation & Destination: Evidence that the communication was received by the intended recipient.

Availability Service

Both X.800 and RFC 2828 characterize availability as the possession of a system or system resource that is available for use upon interest by a permitted system entity in accordance with the system's performance specifications. A multitude of assaults might cause the loss or decrease of availability. Some of these assaults may be mitigated by automated countermeasures such as identification and encryption, while others need physical intervention to avoid or recover from the loss of availability of distributed system pieces.

Advantages of Security Services in Computer Networks

Easy accessibility

Computer networks enable simple access to data, assets, and online services provided by anywhere. Users may work remotely, access instructional materials, and retrieve private data. Email, instant chat, and video conferencing provide seamless communication and cooperation. Resources may be pooled and distributed, lowering costs and improving usage. Modern networks of computers are simple to navigate. So, even whether you are a child or a newcomer to technology, you will find it simple to connect.


Flexibility means that various people can investigate different topics based on their needs. Computer networks offer a variety of options for sharing certain pieces of information. Consider e-mail or messaging applications such as WhatsApp.

Convenient Resource Sharing

A computer network's primary goal is to allow users to share resources with one another. You can utilize shared resources like printers, scanners, and photocopiers. Resource sharing is significant for large firms because it allows them to interact with their employees via a single common network.


Computer networks enhance connectedness regardless of one's location. The epidemic highlighted this benefit, with individuals frequently using video call tools such as Zoom as well as Google Documents to communicate with friends and coworkers.


Computer networks give security through permission. User IDs and passwords are used for authorization. As a result, once we log in, we can only do so if our information matches exactly what is contained in the database.

Excellent Storage Capacity

Organizations have a lot of data that has to be kept. They must do this by storing them on a central server.A centralized server is a distant server that may be accessed by all employees. So, if one person loses the data, the others will still have it.

Reduced Cost

Cost can be one of the most important considerations when weighing the benefits and drawbacks of a certain technology. In networking, a centralized server is used to allow businesses to keep files in one location, hence lowering file storage costs.

Enhanced Collaboration

A computer network allows people to readily share files, papers, and information with one another, which makes it easier to collaborate on projects and activities. This can result in enhanced efficiency and effectiveness in the workplace. Furthermore, computer networks frequently incorporate communication technologies like email and instantaneous messaging, which enable real-time contact and cooperation independent of physical location. Overall, computer networks provide seamless cooperation and teamwork.

Disadvantages of Security Services in Computer Networks

Lack of Robustness

Networked computers rely on a central server. When the central server fails or has a problem, every network device will stop working. This is a significant disadvantage owing to reliance on just one server.

Spread of Computer Viruses

Because computers on a network are linked together, it is quite likely that once one of them becomes infected with the virus, others will as well. This spread has the potential to cause systemic harm. Furthermore, if the main computer becomes corrupted, the network will suffer greatly.

Expensive to Set Up and Maintain

Computer networks save money on sharing resources and data storage, but they can have high installation costs. Furthermore, maintaining networked computers is an expensive and time-consuming process.

Lack of Productivity

Because a network has several advantages and uses, it is unavoidable that multiple services will be used concurrently, causing distraction. When a result, productivity concerns are widespread when staff focus on a variety of duties.

Health Concerns

The computer network allows access to a wide range of services, including entertainment, games, and movies. As a result, you become addicted to the material, leading to excessive usage of these services. Excessive screen time promotes fatigue, eye strain, and physical ache.

Reduces the Capacity to Retain and Evaluate Information

People's capacity to recall crucial knowledge is deteriorating as computer networks store massive volumes of data and handle basic requests in fractions of seconds. Even processing fundamental information is a chore, as people increasingly rely on networks of computers to do it for them.

Unauthorized Access

When several devices are attached to the network, you face a higher risk of illegal access and information breaches. Hackers can exploit network infrastructure flaws or obtain access to sensitive data using a single infected device. This can result in the theft of sensitive or private data, monetary damages, and reputational harm for persons or organizations. To reduce this risk, network managers must deploy strong security measures like firewalls, encryption, and frequent software upgrades to safeguard the network and its associated devices from cyberattacks.


In conclusion, installing effective security services is critical for every organization that wishes to protect its sensitive data from hostile assaults and hackers. Businesses may use these services to guarantee that their systems are always secure and that they meet the regulatory criteria imposed by regulators and customers. Finally, investing in superior network security services can help firms to secure sensitive data while also maintaining positive customer connections in the long run.

Network security is vital because it protects organizations from expensive cyberattacks that might result in loss of information or system failure. Organizations can use secure networks to protect their private information from bad actors and hackers. Implementing robust protocols for network safety can also assist limit the chance of harm caused by a breach on the computer or server?

Furthermore, security services assist firms in meeting regulatory requirements and industry standards. Organizations are increasingly being obliged by authorities and consumers to achieve particular criteria for securing their systems from possible threats. Organizations that have a strong network security policy may demonstrate meeting these criteria while still maintaining positive customer connections.

So, let us be cautious, educate one about emerging dangers, and take proactive steps to improve our digital castles against vulnerabilities in computer security. In doing so, we help to protect the digital world, guaranteeing a more secure and safe online future for everyone.