You are currently viewing Tutorial on Network Quality of Services: DIFFSERV INTSERV

Tutorial on Network Quality of Services: DIFFSERV INTSERV

Are you looking to improve the network quality of services for your organization? Look no further! In this tutorial, we will delve into the world of DIFFSERV and INTSERV, two key approaches to enhancing network performance. Whether you’re an IT professional or a business owner, understanding these concepts is crucial for optimizing your network’s efficiency. So, let’s dive in and explore the ins and outs of DIFFSERV and INTSERV, and how they can elevate your network quality of services to new heights.

Understanding Network Quality of Service (QoS)

In today’s digital landscape, where businesses heavily rely on networks to transmit data and ensure smooth communication, it is crucial to have a clear understanding of Network Quality of Service (QoS). This section aims to define Network QoS and highlight its importance in the realm of networking.

Definition of Network Quality of Service

Network Quality of Service (QoS) refers to the set of techniques and mechanisms employed to manage and prioritize network traffic based on predefined parameters. It involves ensuring optimal performance, reliability, and efficiency of network services and applications.

QoS mechanisms monitor and control network traffic to guarantee consistent and predictable levels of performance for different types of data, such as voice, video, and critical business applications. By assigning appropriate priority levels to data packets, QoS helps prevent congestion, minimize latency, and maintain the overall quality of network services.

Importance of Network Quality of Service

Reliable and efficient network performance is paramount for businesses and organizations of all sizes. Here are a few key reasons why Network QoS holds significant importance:

  1. Enhanced User Experience: Network QoS ensures a consistent and seamless user experience by eliminating disruptions and minimizing delays in data transmission. This is particularly critical for real-time applications like video conferencing or online gaming, where even slight latency can hinder performance and user satisfaction.
  2. Support for Business-Critical Applications: Many businesses rely on applications that require a high level of network performance, such as customer relationship management (CRM) systems, enterprise resource planning (ERP) software, and voice over internet protocol (VoIP) applications. Network QoS ensures these critical applications receive the necessary resources and prioritization to function smoothly.
  3. Efficient Bandwidth Management: QoS mechanisms enable businesses to allocate network bandwidth according to their specific requirements. By prioritizing time-sensitive applications and limiting bandwidth for non-critical tasks, organizations can optimize network utilization and prevent congestion.
  4. Minimized Downtime and Network Issues: With effective QoS implementation, organizations can proactively manage network congestion, prevent bottlenecks, and reduce the likelihood of network downtime or performance degradation. This helps maintain uninterrupted productivity and prevents potential revenue loss associated with network issues.
  5. Improved Scalability: As businesses grow and network demands increase, QoS allows for effective scalability. By efficiently managing network resources and prioritizing critical traffic, organizations can accommodate expanding user bases and ensure consistent performance without compromising network integrity.

In summary, understanding Network Quality of Service (QoS) is essential for businesses aiming to provide reliable, efficient, and high-performing network services. By effectively managing network traffic, prioritizing critical applications, and ensuring a smooth user experience, organizations can optimize their network infrastructure and support their strategic goals.

Different Approaches to Network Quality of Service

Quality of Service (QoS) is a key aspect in modern networking, as it allows for the prioritization and efficient delivery of network traffic. In order to achieve QoS, different approaches have been developed. In this section, we will explore two prominent approaches: Differentiated Services (DiffServ) and Integrated Services (IntServ).

Differentiated Services (DiffServ)

DiffServ is a scalable and flexible QoS mechanism that operates at the network layer of the OSI model. It aims to provide differentiated treatment to various types of network traffic based on their specific requirements. DiffServ achieves this by dividing network traffic into different classes or service levels, each with its own priority and quality parameters.

One of the key features of DiffServ is the concept of Differentiated Service Code Points (DSCPs). These are 6-bit values that are embedded within the IP header of network packets to indicate the desired treatment for that packet. By assigning appropriate DSCPs to packets, network administrators can ensure that time-sensitive or critical traffic receives higher priority and is delivered with low latency and minimal packet loss.

DiffServ achieves its scalability by employing a hierarchical model, where different routers in the network collaborate to provide the desired QoS for each traffic class. This allows for efficient resource utilization and avoids the need for complex per-flow management.

Integrated Services (IntServ)

IntServ, on the other hand, is an older QoS model that operates at the transport layer of the OSI model, specifically within the TCP/IP suite. Unlike DiffServ, IntServ aims to provide QoS on a per-flow basis, offering dedicated resources and guarantees for individual network flows.

IntServ achieves its objectives through the use of two signaling protocols: Resource Reservation Protocol (RSVP) and Integrated Services Control Protocol (ISCP). RSVP is responsible for setting up and maintaining the required resources along the entire path of the flow, while ISCP handles the negotiation and reservation of resources at each intermediate router.

By using IntServ, applications can request specific QoS parameters, such as bandwidth, delay, and packet loss, for their flows. This ensures that time-critical applications, such as real-time voice or video streaming, receive the necessary resources and are able to maintain a high level of performance.

However, the main limitation of IntServ is its lack of scalability. Since it requires per-flow state information and resource reservations at every router along the path, it can become impractical to deploy in large-scale networks with a significant number of flows.

In conclusion, both DiffServ and IntServ offer different approaches to achieving QoS in network environments. DiffServ provides a scalable and flexible solution by categorizing traffic into different service levels, while IntServ offers per-flow guarantees but lacks scalability. The choice between these approaches depends on the specific requirements and constraints of the network deployment.

DiffServ and IntServ Explained

Dealing with network quality of service (QoS) can be a complex and challenging task. Two popular approaches to QoS management are Differentiated Services (DiffServ) and Integrated Services (IntServ). In this section, we will explore the architectures of DiffServ and IntServ to help you gain a better understanding of their functionalities and how they operate within a network environment.

DiffServ Architecture

DiffServ is a scalable and flexible QoS model that provides a simple and efficient way to prioritize network traffic. It accomplishes this by classifying and marking packets based on their priority levels, allowing routers and switches to make intelligent forwarding decisions. Here’s a breakdown of the key components of DiffServ:

  1. Traffic Classification: DiffServ employs a classification mechanism that categorizes packets into different classes or behavior aggregates (BA). These classes are assigned specific service level agreements (SLAs) and quality parameters based on their priority requirements.
  2. Per-Hop Behaviors: Once packets are classified, DiffServ routers apply a specific behavior to each class of traffic, known as the per-hop behavior (PHB). The PHB determines how a router should treat and prioritize packets belonging to a particular class. Common PHBs include best-effort, expedited forwarding, and assured forwarding.
  3. Traffic Conditioning: To maintain the integrity of the DiffServ QoS model, traffic conditioning mechanisms, such as traffic shaping and policing, are implemented. These mechanisms help regulate the flow of traffic and ensure that packets conform to their assigned SLAs.

IntServ Architecture

Unlike DiffServ, which focuses on scalability and simplicity, Integrated Services (IntServ) aims to provide a more fine-grained QoS approach for individual flows in a network. It requires more management overhead but offers better control over network resources. Here’s an overview of the IntServ architecture:

  1. Resource Reservation: With IntServ, applications can request specific QoS guarantees from the network through a process called resource reservation. This involves setting up a reservation state in each network device along the path of the flow, ensuring that the requested resources are available.
  2. Signaling Protocol: To establish and maintain the reservation state, IntServ relies on a signaling protocol called the Resource Reservation Protocol (RSVP). RSVP enables applications to communicate their QoS requirements to the network and make reservations accordingly.
  3. Per-Flow QoS: IntServ operates on a per-flow basis, meaning that it treats each flow individually and allocates resources accordingly. This level of granularity allows for precise control over the QoS experienced by each flow’s packets.

Both DiffServ and IntServ serve distinct purposes in QoS management. DiffServ offers a scalable and efficient approach, suitable for large networks with diverse traffic types. On the other hand, IntServ provides fine-grained control over individual flows but requires more administrative overhead. Understanding these architectures is crucial for effectively implementing QoS strategies that meet the specific needs of your network.

Key Features and Characteristics of DiffServ

DiffServ, which stands for Differentiated Services, is a QoS (Quality of Service) model used to ensure efficient network performance and prioritize traffic based on specific requirements. In this section, we will delve into the key features and characteristics of DiffServ, including DiffServ Code Points (DSCP), Per-Hop Behavior (PHB), Assured Forwarding (AF) Classes, and Expedited Forwarding (EF) Class.

DiffServ Code Points (DSCP)

DiffServ Code Points (DSCP) are a crucial aspect of DiffServ architecture. They are used to classify and mark packets, enabling network devices to handle traffic with appropriate priority levels. DSCP values are encoded within the IP packet header’s Differentiated Services Field (DS Field), allowing routers and switches to efficiently navigate traffic flows.

DSCP values range from 0 to 63, divided into different classes such as default, network control, and class selectors. Each DSCP value corresponds to a specific traffic class, defining the level of service it should receive.

Per-Hop Behavior (PHB)

Per-Hop Behavior (PHB) is a term used to describe the desired forwarding behavior for a particular class of traffic within DiffServ. PHB determines how packets belonging to a specific DSCP value should be treated at each hop or network node along the transmission path.

PHB defines the forwarding treatment, such as queuing, dropping, or forwarding without delay, that should be applied to packets based on their assigned DSCP. It ensures consistent handling of traffic throughout the network, enabling the delivery of QoS guarantees.

Assured Forwarding (AF) Classes

Assured Forwarding (AF) classes are a set of four classes within DiffServ that provide different levels of forwarding assurances for network traffic. These classes are classified as AF1, AF2, AF3, and AF4, with each offering a different degree of priority and delivery guarantees.

AF classes are further divided into subgroups, referred to as AFx, where x ranges from 1 to 3. Each subgroup has three drop precedence levels, denoted as low, medium, and high. By assigning packets to the appropriate AF class and drop precedence, network administrators can ensure preferential treatment for critical traffic while maintaining fairness across different traffic flows.

Expedited Forwarding (EF) Class

The Expedited Forwarding (EF) class is designed to provide a premium forwarding treatment for real-time applications that require low-latency and low-jitter transmission. It offers the highest priority within the DiffServ architecture, giving real-time traffic like voice and video the necessary resources to achieve optimal performance.

The EF class is allocated a specific DSCP value, and any packet marked with this DSCP receives expedited forwarding treatment throughout the network. This ensures minimal delay, loss, and jitter, making it suitable for time-sensitive applications that demand consistent and reliable delivery.

In conclusion, DiffServ offers a flexible and scalable approach to Quality of Service. By utilizing DiffServ Code Points (DSCP), Per-Hop Behavior (PHB), Assured Forwarding (AF) classes, and Expedited Forwarding (EF) class, network administrators can effectively prioritize traffic and ensure efficient transmission of critical data. Applying DiffServ principles enhances network performance, optimizes resource utilization, and ultimately improves the end-user experience.

Key Features and Characteristics of IntServ

IntServ (Integrated Services) is a network model that aims to provide end-to-end Quality of Service (QoS) guarantees for real-time and multimedia applications. It focuses on ensuring the delivery of packets with specific QoS requirements across networks. In this section, we will explore the key features and characteristics of IntServ, including the Resource Reservation Protocol (RSVP), Traffic Specification (TSpec), Admission Control, and the two services it offers: Integrated Services Guaranteed (ISG) and Controlled Load (CL) Services.

Resource Reservation Protocol (RSVP)

RSVP is a signaling protocol used in IntServ to reserve network resources along a predetermined path for a particular communication session. It enables the network to reserve and allocate the necessary bandwidth, buffer space, and processing resources to ensure a smooth transmission of data packets. RSVP works by sending control messages between the sender and the receiver to establish and maintain the reservation state in the network.

Traffic Specification (TSpec)

TSpec is the mechanism used in IntServ to describe the traffic characteristics and QoS requirements of a communication session. It includes parameters such as the required bandwidth, delay, jitter, and packet loss tolerance. By specifying the TSpec, applications can communicate their specific QoS needs to the network, allowing the network to allocate resources accordingly.

Admission Control

Admission Control is a critical component of IntServ that performs the task of verifying whether the requested QoS parameters can be met by the network before admitting a new communication session. It evaluates the available network resources and checks if the requested QoS parameters can be guaranteed without degrading the performance of existing sessions. If the resources are insufficient, the admission control mechanism may reject the new session or negotiate for different QoS parameters.

Integrated Services Guaranteed (ISG) Service

The ISG service is one of the two services provided by IntServ. It guarantees a specific QoS level for an admitted communication session. Once a session is admitted, the network reserves the necessary resources and ensures that the requested QoS parameters are maintained throughout the session. ISG is typically used for applications that require a deterministic and assured level of QoS, such as voice and video conferencing.

Controlled Load (CL) Service

The CL service is the second service offered by IntServ. It aims to provide a QoS level that closely matches the best-effort service of IP networks. It strives to maintain low delay, low jitter, and minimal packet loss, but without the strict guarantees of the ISG service. CL is suitable for applications that can tolerate some degree of QoS variation, such as audio streaming and online gaming.

In conclusion, IntServ offers a comprehensive set of features and characteristics to ensure end-to-end QoS guarantees for real-time and multimedia applications. With RSVP for resource reservation, TSpec for traffic specification, and admission control for session management, IntServ can provide both ISG and CL services to meet the diverse QoS requirements of different applications. By leveraging these capabilities, network architects can design networks that deliver a reliable and predictable user experience for a wide range of services.

Choosing Between DiffServ and IntServ

When it comes to managing network quality of service (QoS), network administrators often face the decision of choosing between Differentiated Services (DiffServ) and Integrated Services (IntServ) architectures. Both approaches have their own advantages and disadvantages, and understanding these factors is crucial for making an informed decision. In this section, we will explore the factors to consider, as well as the advantages and disadvantages of both DiffServ and IntServ.

Factors to Consider

Before deciding between DiffServ and IntServ, several factors need to be taken into account. These factors include the specific requirements of the network, the level of control needed over QoS parameters, the scalability of the solution, and the complexity of implementation.

  1. Specific Network Requirements: Consider the specific needs and characteristics of your network. Different networks may have varying QoS requirements, such as prioritizing real-time applications, ensuring low latency for certain services, or maintaining a consistently high bandwidth for data transfers.
  2. Control over QoS Parameters: Evaluate the level of control you require over QoS parameters. DiffServ offers a more simplified and scalable approach, where QoS policies are applied across traffic classes. On the other hand, IntServ provides fine-grained control over individual flows, allowing for precise QoS guarantees but requiring more configuration and management overhead.
  3. Scalability: Consider the scalability of the solution. DiffServ is designed to handle large-scale networks with a high volume of traffic, making it suitable for enterprise-level deployments. Conversely, IntServ is more resource-intensive and may not scale as effectively in larger networks.
  4. Implementation Complexity: Assess the complexity of implementing and managing the chosen QoS architecture. DiffServ is generally easier to implement and configure, requiring less overhead in terms of configuration and maintenance. IntServ, on the other hand, can be more complex and time-consuming to set up, especially when dealing with a large number of flows and fine-grained QoS requirements.

Advantages and Disadvantages of DiffServ


  • Simplicity: DiffServ offers a simpler and more scalable approach to QoS management, making it easier to implement and manage in large networks.
  • Flexibility: With DiffServ, QoS policies can be applied to traffic classes, allowing for more efficient control over different types of network traffic.
  • Resource Efficiency: The simplified nature of DiffServ reduces the overhead associated with QoS management, resulting in better resource utilization.


  • Lack of Granularity: DiffServ provides QoS differentiation on a per-class basis, which may not be sufficient for applications that require precise flow-level guarantees.
  • Limited End-to-End Control: DiffServ is primarily focused on providing differentiated QoS within individual network domains, which means end-to-end control may be limited, especially in multi-domain networks.
  • Difficulties with SLA Enforcement: Enforcing Service Level Agreements (SLAs) can be challenging with DiffServ due to the absence of end-to-end guarantees for specific flows.

Advantages and Disadvantages of IntServ


  • Fine-Grained Control: IntServ allows for fine-grained control over individual flows, enabling precise QoS guarantees for critical applications.
  • End-to-End QoS: With IntServ, end-to-end QoS guarantees can be provided on a per-flow basis, ensuring consistent performance across multiple network domains.
  • Suitable for Real-Time Applications: IntServ is well-suited for real-time applications that require stringent QoS guarantees, such as voice and video conferencing.


  • Complex Configuration: IntServ typically requires more complex configuration and management, especially when dealing with a large number of flows and QoS parameters.
  • Increased Overhead: The granular nature of IntServ can result in increased overhead, as resources need to be allocated on a per-flow basis, potentially impacting overall network performance.
  • Limited Scalability: Due to its resource-intensive nature, IntServ may face scalability challenges in larger networks, making it less suitable for enterprise-grade deployments.

By carefully considering these factors and weighing the advantages and disadvantages, network administrators can make an informed decision when choosing between DiffServ and IntServ for their network’s QoS management needs.


In conclusion, understanding the network quality of services (QoS) frameworks, DIFFSERV and INTSERV, is essential for optimizing network performance. DIFFSERV provides a scalable and efficient solution for classifying and prioritizing network traffic, allowing for effective management of traffic congestion. On the other hand, INTSERV offers a more individualized approach by reserving network resources for specific applications, ensuring a reliable and predictable service delivery.

By implementing either DIFFSERV or INTSERV, network administrators can enhance the overall user experience by prioritizing critical applications and ensuring the efficient utilization of network resources. It is crucial to evaluate the specific requirements of your network and consider the pros and cons of each framework before making a decision.

In today’s digital landscape, where the demand for seamless connectivity continues to grow, having a strong understanding of QoS frameworks like DIFFSERV and INTSERV is paramount. By effectively managing network traffic and prioritizing critical applications, businesses can ensure optimal performance and provide a superior user experience to their customers.

Discover expert-led telecom training courses in Delhi, India at the Institute of Telecom Trainings. Enhance your skills and advance your career. Enroll today!

Looking for telecom training courses in Delhi, India? Institute of Telecom Trainings offers industry-certified programs to boost your knowledge and career prospects. Enroll now!

Get ahead in the telecom industry with specialized training courses at Institute of Telecom Trainings in Delhi, India. Join us and unlock your potential today!

Master the essentials of telecom with our comprehensive training courses at Institute of Telecom Trainings in Delhi, India. Equip yourself with in-demand skills. Enroll now!

Boost your telecom career with comprehensive training courses at the Institute of Telecom Trainings in Delhi. Enroll now for hands-on learning and industry insights.

Looking for telecom training courses in Delhi, India? Discover top-notch programs at the Institute of Telecom Trainings. Start your journey to success today!

Develop your skills in the booming telecom industry. Join the Institute of Telecom Trainings in Delhi, India, for expert-led courses and practical knowledge.

Stand out in the competitive telecom sector with specialized training from the Institute of Telecom Trainings in Delhi. Explore our courses for a successful career.

Enhance your telecom skills with professional training at the Institute of Telecom Trainings in Delhi. Join us to unlock new career opportunities today!

Discover comprehensive telecom training courses in Delhi, India at the Institute of Telecom Trainings. Take your career to new heights – enroll now!

Looking for telecom training courses in Delhi, India? Look no further! Institute of Telecom Trainings offers expert-led programs for aspiring professionals. Enroll today!

Develop a strong foundation in telecom with industry-focused courses at the Institute of Telecom Trainings in Delhi, India. Begin your journey towards success – sign up now!

Enhance your telecom skills at Institute of Telecom Trainings in Delhi. Join our comprehensive training courses today and take your career to new heights!

Looking for telecom training courses in Delhi? Institute of Telecom Trainings offers expert-led programs to help you become industry-ready. Enroll now!

Get industry-relevant telecom training courses in Delhi, India at Institute of Telecom Trainings. Take the first step towards a successful career. Enroll today!

Institute of Telecom Trainings in Delhi offers specialized telecom training courses. Gain the skills and knowledge you need to excel in the telecom industry. Enroll now!

Enhance Your Telecom Skills at Delhi’s Leading Institute. Join Our Comprehensive Telecom Training Courses Today & Unleash Your Potential! Enroll Now.

Discover the Best Telecom Training Courses in Delhi at Institute of Telecom Trainings. Equip Yourself with In-Demand Telecom Skills. Enroll Today!

Unlock Lucrative Career Opportunities with Telecom Training Courses in Delhi at Institute of Telecom Trainings. Take the First Step Towards Success. Enroll Now!

Boost Your Telecom Career with Top-notch Training Courses in Delhi at Institute of Telecom Trainings. Gain Practical Skills for Real-world Success. Enroll Today!

Boost your telecom career with comprehensive training courses at Institute of Telecom Trainings in Delhi. Enroll now for hands-on learning and expert guidance!

Looking for top-notch telecom training courses in Delhi? Institute of Telecom Trainings offers industry-leading programs to help you excel in your career. Join us today!

Take your telecom skills to the next level with Institute of Telecom Trainings in Delhi. Our expert-led courses provide practical knowledge and real-world experience. Enroll now!

Get certified in telecom training courses at Institute of Telecom Trainings, Delhi. Learn from industry experts and gain the skills needed to succeed in the telecom industry.

Leave a Reply