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)

Model

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

Misc

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

Difference between Transport and Network Layer

When it comes to the Internet, it is essential to understand the different layers that make up the network. The two most important layers are Transport Layer and Network Layer. Each layer has a different role to play in the functioning of the network. The Transport Layer is responsible for the reliable delivery of data packets over a network, while the Network Layer is responsible for routing data packets over a network. In this article, we will look at the differences between Transport Layer and Network Layer, as well as the importance of each layer. We will also examine the protocols associated with each layer, and discuss how these layers interact to create a reliable network. By the end of this article, you should better understand these two important layers and how they work together to provide an effective network.

Transport Layer

The Transport Layer (layer 4 of the OSI model) is responsible for the end-to-end data transfer between devices. It provides services such as flow control, error control, and segmentation/reassembly of data. It acts as an intermediary between the upper layers (Session, Presentation, and Application Layers) and the lower layers (Network, Data Link, and Physical Layers) of the OSI model. It provides a communication interface between applications running on different devices and the underlying network infrastructure.

Functions of the Transport Layer

  • Segmentation and reassembly of data: The Transport Layer breaks down large data packets into smaller segments easily handled by the lower layers. It also reassembles the segments back into the original data packet at the receiving end. This process is necessary because the lower layers may have different limitations on the size of the data packets they can handle.
  • Flow control: The Transport Layer provides flow control to ensure that the sender does not overwhelm the receiver with too much data. It regulates the rate at which data is sent, preventing the sender from sending more data than the receiver can handle.
  • Error checking and correction: The Transport Layer ensures the reliability of data transfer by providing error checking and correction. It detects and corrects errors that may occur during data transmission and retransmits any lost or corrupted data.

Examples of Transport Layer protocols

  1. Transmission Control Protocol (TCP): TCP is a connection-oriented protocol that provides a reliable, error-checked, and flow-controlled data transfer service. It establishes a virtual connection between the sender and receiver and guarantees that all data sent is received. Many common internet applications use TCP such as HTTP, FTP, and SMTP.
  2. User Datagram Protocol (UDP): UDP is a connectionless, unreliable protocol that does not guarantee the delivery of data. It does not establish a virtual connection, provides no flow control, and does not perform error checking. It is faster and more efficient than TCP, but it is more suited for applications that do not require guaranteed delivery of data. Examples of UDP applications include DNS, DHCP, and streaming media.

In general, the choice of transport layer protocol depends on the application's specific requirements. Applications that require a reliable and error-checked data transfer will typically use TCP, while applications that are less sensitive to errors or have real-time requirements will typically use UDP or other protocols.

Network Layer

The Network Layer (layer 3 of the OSI model) is responsible for routing and forwarding data packets across multiple links in a network. It is responsible for determining the best path for data to travel and handling issues such as addressing and congestion control. It acts as an intermediary between the upper layers (Transport, Session, Presentation, and Application Layers) and the lower layers (Data Link and Physical Layers) of the OSI model. It provides a communication interface between devices running different transport layer protocols and the underlying network infrastructure.

Functions of the Network Layer

  • Routing of data packets: The Network Layer determines the best path for data packets to travel through the network. It uses routing algorithms and routing tables to make this decision. Routing is the process of forwarding data packets from one device to another based on the packet's destination address.
  • Addressing: The Network Layer assigns unique addresses to each device on the network. This allows devices to identify each other and determine where to send data packets. The most common network layer protocol, Internet Protocol (IP), uses IP addresses.
  • Error checking and correction: The Network Layer ensures the reliability of data transfer by providing error checking and correction. It detects and corrects errors that may occur during data transmission and retransmits any lost or corrupted data.

Examples of Network layer protocols

  1. Internet Protocol (IP): IP is the most commonly used network layer protocol. It is responsible for routing data packets through an internetwork, such as the internet. IP addresses are used to identify devices on a network and determine the path for data packets to travel.
  2. Internetwork Packet Exchange (IPX): IPX is a network layer protocol developed by Novell for use in their NetWare operating system. It uses a unique addressing scheme called network addresses to identify devices on a network.
  3. AppleTalk DDP: AppleTalk DDP is a network layer protocol developed by Apple for their Macintosh operating system. It is responsible for routing data packets through an AppleTalk network. It uses a unique addressing scheme called network addresses and node addresses to identify devices on a network.

In general, the Network Layer plays a critical role in the functioning of networks by routing data packets, assigning unique addresses, and providing error checking and correction. The choice of network layer protocol depends on the specific requirements of the application or network.

Here is a comparison table between the Transport Layer and the Network Layer in the OSI model:

Comparison IndexTransport Layer Network Layer
PurposeTo provide end-to-end communication between devices and ensure reliable delivery of data.To route and forward packets of data between devices on a network and ensure the correct delivery of data to its destination.
Key functionsSegmentation, flow control, error checking, multiplexing/de-multiplexing, end-to-end communicationAddressing, routing, path selection, packet switching, congestion control, error handling
Protocol examplesTCP (Transmission Control Protocol), UDP (User Datagram Protocol)IP (Internet Protocol), ICMP (Internet Control Message Protocol), OSPF (Open Shortest Path First), BGP (Border Gateway Protocol)
Examples of servicesFile transfer, email, remote login, virtual private networks (VPNs)Internet connectivity, routing of packets between different networks, network-layer firewalls, Quality of service (QoS)

How these two layers work together

The two layers work together to ensure that data is delivered reliably and efficiently. Data is first passed down from the Application layer to the Transport layer, where it is divided into smaller packets and given a logical address. The Transport layer then passes the packets to the Network layer, which uses routing algorithms to determine the best path for the packets to travel. The Network layer then sends the packets to the next device in the network, where they are passed back up through the OSI layers and reassembled into their original form at the destination device.

Examples of scenarios where one layer is more important than the other

In a scenario where the network is congested with high traffic, the Network layer would be more important as it is responsible for finding the best path for data to travel, and it controls the logical addressing of devices, allowing for efficient data transmission.

In a scenario where data integrity and reliability are crucial, such as in a medical monitoring system, the Transport layer would be more important as it provides services such as flow control, error checking, and retransmission of lost packets to ensure that data is delivered without errors.

Another example of a scenario where one layer is more important than the other is in a situation where security is a primary concern. In this case, the Network layer would be more important because it provides security features such as access control and encryption. For example, the Network layer could use firewalls to block unauthorized access to the network and Virtual Private Networks (VPNs) to encrypt data as it is transmitted over the internet.

In contrast, the Transport layer would be more important in a scenario where low latency is crucial, such as in real-time gaming or video conferencing. It can use techniques such as Quality of Service (QoS) to prioritize certain types of traffic, such as video and audio, over less critical traffic to minimize delay and provide a seamless experience for the user.

Conclusion:

Understanding the Transport and Network layers in networking and communication is important for several reasons.

Firstly, these layers play a critical role in ensuring that data is delivered reliably and efficiently between different devices on a network. With them, recovering data would be quick, and communication would be reliable.

Understanding these layers allows network administrators and engineers to troubleshoot and optimize network performance. By understanding how the Transport and Network layers work and interact with other layers in the networking stack, administrators and engineers can identify and resolve issues causing poor network performance.

Lastly, Understanding the Transport and Network layers is important for developing and implementing new networking technologies and protocols. Understanding how these layers work and interact with other layers in the networking stack is essential for designing and deploying new technologies and protocols that can improve network performance and security.