The document discusses the OSI reference model, which describes how information moves between software applications running on different computers. It has 7 layers, with each layer performing specific network functions and communicating with layers above and below. The principles of dividing networks into layers include defining standardized protocols and minimizing information flow across interfaces. This model facilitates network communication and management.
The OSI model is a layered architecture for networking that breaks down communication functions into 7 distinct layers. Each layer performs a subset of communication functions and relies on the layer below it. Changes to one layer should not require changes in other layers. The layers are physical, data link, network, transport, session, presentation, and application. The physical layer transmits individual bits, the data link layer transmits frames between two nodes, the network layer delivers packets across networks, the transport layer delivers messages between processes, and the upper layers establish communication sessions, define data formats, and provide services to users.
The document discusses the layered architecture model known as the Open Systems Interconnection (OSI) model. The OSI model contains seven layers that each perform a specific communication function and rely on the layer below. It describes the functions of each layer, including the physical, data link, network, transport, session, presentation, and application layers. The layered design philosophy breaks communication tasks into simpler sub-tasks at each independent layer to standardize network communication.
The OSI model defines a standard approach to network communication with 7 layers - physical, data link, network, transport, session, presentation and application. Each layer has a specific function, with the lower layers focusing on physical connectivity and error checking and the upper layers providing services to applications. Information is encapsulated as it moves down the layers and headers are added before being de-encapsulated as it moves up the layers at the receiving end. The model separates network functions and allows components from different vendors to work together.
The document discusses the session layer in networking models. It explains that the session layer controls dialogues and connections between computers, establishing and managing connections between local and remote applications. It provides examples of session layer protocols like OSI and describes the purpose of the session layer is to assist interactions between presentation entities through session administration and dialogue services. The conclusion states that the session layer is responsible for communication between nodes and managing sessions, while noting that TCP/IP is now more commonly used than the OSI model.
The OSI model defines a framework for networking with 7 layers - physical, data link, network, transport, session, presentation and application. Control is passed between layers as data moves up and down the stack. Each layer provides services to the layer above it and receives services from the layer below. Common protocols and technologies are used to implement specific functions at each layer, including routing, addressing, error handling and data formatting.
This document discusses the OSI model and its 7 layers. It describes the layered architecture approach of breaking communication tasks into simpler sub-tasks handled by individual layers. Each layer provides services to the layer above and relies on the layer below. The layers are the physical, data link, network, transport, session, presentation, and application layers. Each layer has specific responsibilities for handling data transmission and communication functions.
The document discusses the OSI 7-layer model created by the International Organization for Standardization in 1984. It describes the 7 layers of the OSI model: physical, data link, network, transport, session, presentation, and application. The physical layer deals with media and hardware, the data link layer handles MAC addressing and LLC, the network layer deals with IP addressing and routing, and the higher layers deal with transport, session communication, encryption/compression, and end-user applications.
The document discusses networking standards organizations and the OSI model. It describes the seven layers of the OSI model and their functions. The layers are application, presentation, session, transport, network, data link, and physical. Data moves down through the layers of one system and up through the layers of the receiving system. Standards organizations like IEEE, ISO, and IETF help establish networking standards and protocols.
The OSI model is a layered architecture for networking that breaks down communication functions into 7 distinct layers. Each layer performs a subset of communication functions and relies on the layer below it. Changes to one layer should not require changes in other layers. The layers are physical, data link, network, transport, session, presentation, and application. The physical layer transmits individual bits, the data link layer transmits frames between two nodes, the network layer delivers packets across networks, the transport layer delivers messages between processes, and the upper layers establish communication sessions, define data formats, and provide services to users.
The document discusses the layered architecture model known as the Open Systems Interconnection (OSI) model. The OSI model contains seven layers that each perform a specific communication function and rely on the layer below. It describes the functions of each layer, including the physical, data link, network, transport, session, presentation, and application layers. The layered design philosophy breaks communication tasks into simpler sub-tasks at each independent layer to standardize network communication.
The OSI model defines a standard approach to network communication with 7 layers - physical, data link, network, transport, session, presentation and application. Each layer has a specific function, with the lower layers focusing on physical connectivity and error checking and the upper layers providing services to applications. Information is encapsulated as it moves down the layers and headers are added before being de-encapsulated as it moves up the layers at the receiving end. The model separates network functions and allows components from different vendors to work together.
The document discusses the session layer in networking models. It explains that the session layer controls dialogues and connections between computers, establishing and managing connections between local and remote applications. It provides examples of session layer protocols like OSI and describes the purpose of the session layer is to assist interactions between presentation entities through session administration and dialogue services. The conclusion states that the session layer is responsible for communication between nodes and managing sessions, while noting that TCP/IP is now more commonly used than the OSI model.
The OSI model defines a framework for networking with 7 layers - physical, data link, network, transport, session, presentation and application. Control is passed between layers as data moves up and down the stack. Each layer provides services to the layer above it and receives services from the layer below. Common protocols and technologies are used to implement specific functions at each layer, including routing, addressing, error handling and data formatting.
This document discusses the OSI model and its 7 layers. It describes the layered architecture approach of breaking communication tasks into simpler sub-tasks handled by individual layers. Each layer provides services to the layer above and relies on the layer below. The layers are the physical, data link, network, transport, session, presentation, and application layers. Each layer has specific responsibilities for handling data transmission and communication functions.
The document discusses the OSI 7-layer model created by the International Organization for Standardization in 1984. It describes the 7 layers of the OSI model: physical, data link, network, transport, session, presentation, and application. The physical layer deals with media and hardware, the data link layer handles MAC addressing and LLC, the network layer deals with IP addressing and routing, and the higher layers deal with transport, session communication, encryption/compression, and end-user applications.
The document discusses networking standards organizations and the OSI model. It describes the seven layers of the OSI model and their functions. The layers are application, presentation, session, transport, network, data link, and physical. Data moves down through the layers of one system and up through the layers of the receiving system. Standards organizations like IEEE, ISO, and IETF help establish networking standards and protocols.
This document provides an overview of different types of computer networks. It discusses local area networks (LANs) that connect computers within a confined geographic area like a building. It also discusses wide area networks (WANs) that combine multiple LANs across greater distances using technologies like phone lines. The document outlines two main categories of networks: peer-to-peer and server-based. It also provides a detailed explanation of the seven-layer OSI model and the functions of each layer, including the physical, data link, network, transport, session, presentation and application layers.
The document provides an overview of the seven-layer OSI model for computer networking. It describes each layer and its functions, including the physical, data link, network, transport, session, presentation and application layers. The physical layer defines cable specifications, the data link layer provides addressing and error detection, and the network layer enables routing between different networks using logical addresses. Higher layers include the transport layer for reliable data transmission, and the session, presentation and application layers for establishing communication between applications and presenting data to the end user.
This document provides an overview of the Open Systems Interconnection (OSI) model, which is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. It describes how data moves from one computer to another networked computer by dividing the tasks involved into 7 smaller layers, with each layer performing a specific communication task and providing services to adjacent layers to reduce complexity. The 7 layers are the physical, data link, network, transport, session, presentation, and application layers.
The OSI model is a reference model developed by ISO in 1984 for communication across different networks and applications. It defines the communication process into 7 layers, with layers 7 through 4 dealing with end-to-end communication and layers 3 through 1 dealing with communication between network devices. The 7 layers are: layer 7 application layer, layer 6 presentation layer, layer 5 session layer, layer 4 transport layer, layer 3 network layer, layer 2 data link layer, and layer 1 physical layer. Each layer has a specific function in the communication process.
The document discusses the Open Systems Interconnection (OSI) model, which defines seven layers for data communication between any two systems. The seven layers are the physical, data link, network, transport, session, presentation, and application layers. Each layer has a specific role, with the physical layer concerned with bit transmission and the application layer dealing with high-level services like email. The OSI model allows for flexible and robust network architecture design.
OSI Model - Open Systems InterconnectionAdeel Rasheed
The Open Systems Interconnection (OSI) reference model has served as the most basic elements of computer networking since the inception in 1984. The OSI Reference Model is based on a proposal developed by the International Standards Organization (ISO).
The document discusses the OSI model, which divides networking into 7 layers (physical, data link, network, transport, session, presentation, application) and standardizes network communication. It established the need for standards to ensure interoperability between different network implementations and describes the basic functions of each OSI layer and how data is encapsulated as it moves down the layers of the model.
The document discusses the OSI reference model, which defines 7 layers of network communication: physical, data link, network, transport, session, presentation, and application. Each layer has a specific role, such as the physical layer being responsible for transmitting raw bits over a communication medium and the network layer handling routing between devices. The layered approach separates network functionality and allows different aspects of communication to be developed independently.
7 Layers OSI model description with 3 unofficial Layers.Kanishk Raj
OSI reference model all seven layers description with 8,9,&10 not official layers that is also important in an organization ,when design the effective Network output.
The document discusses the OSI reference model, which is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. The OSI model structures network architecture into 7 layers, with each layer performing a specific set of functions. It defines the protocols used for communication between the layers of networked systems and allows networks to work together. The 7 layers are physical, data link, network, transport, session, presentation, and application layers. Each layer focuses on a specific task and provides services for the layer above it, hiding the details of its own implementation and the layers below it.
The document discusses the OSI model, which is a conceptual model that characterizes and standardizes the communication functions of a networking system without regard to their underlying internal structure and technology. It describes the seven layers of the OSI model from physical layer to application layer, and explains the functions of each layer, including physical addressing, framing, routing, error control, and providing services to applications. The layered architecture allows complete interoperability between different systems.
The OSI model is a standard reference model for network communication that consists of 7 layers:
1) The physical layer is responsible for the movements of individual bits from one hop to the next.
2) The data link layer is responsible for moving frames from one hop to the next.
3) The network layer is responsible for the delivery of individual packets from the source host to the destination host.
The OSI model divides network communication into 7 layers, with each layer building on the ones below it. The physical layer is responsible for physical interface and transmission, while the data link layer handles addressing and error checking. The network layer uses logical addressing to determine the best path for packet delivery. Higher layers include the transport layer, which segments data and ensures reliable delivery, as well as the session, presentation and application layers which handle user interactions. The OSI model provides a framework for designing networking hardware and software by standardizing the functions of each layer.
OSI (Open Systems Interconnection) is defined as reference model that is used for how applications can impart over the network. It is the conceptual model that is used for comprehension relationships. Copy the link given below and paste it in new browser window to get more information on OSI Model:- www.transtutors.com/homework-help/computer-science/osi-model.aspx
Osi Layer model provided by TopTechy.comVicky Kamboj
The document summarizes the Open Systems Interconnection (OSI) model, which describes how information is transferred between software applications running on different computers connected over a network. It explains that the OSI model defines 7 layers - physical, data link, network, transport, session, presentation and application layer - through which data passes as it travels from the source to destination. Each layer adds header information and communicates with its corresponding layer in the source/destination computer as well as with layers above and below it to successfully transfer information between applications across a network.
The document discusses the seven-layer Open Systems Interconnection (OSI) model for data communication between networked systems. It describes each layer of the OSI model including: the physical layer which deals with transmission and signaling of raw bit streams over a communication channel; the data link layer which transforms the physical layer into a reliable link; the network layer which is responsible for logical addressing and routing of packets across multiple networks; the transport layer which ensures complete and error-free delivery of message segments; the session layer which establishes and synchronizes interactions between systems; the presentation layer which formats data for transmission; and the application layer which provides user interfaces and services. Each layer uses the services of lower layers and provides services to higher layers.
The document discusses the 7 layers of the OSI model, with each layer adding headers or trailers to data as it passes through - the physical layer is the lowest layer dealing with transmission of raw data, followed by the data link layer, network layer, transport layer, session layer, presentation layer, and application layer as the highest layer of data exchange between applications.
The document describes the 7-layer OSI reference model developed by ISO in 1983 to standardize communication between systems and devices. It provides an overview of each layer, including the physical layer which defines electrical specifications, the data link layer which handles framing and error control, the network layer which performs routing between networks, the transport layer which provides reliable data transfer, the session layer which establishes connections, the presentation layer which translates between data formats, and the application layer which interacts directly with software applications. The model arranges the layers with each building upon the previous to standardize communication functions across different systems.
The document discusses network models including the OSI model and TCP/IP model. It describes the seven layers of the OSI model and the functions of each layer. It also discusses the four layers of the TCP/IP model and compares the two models, noting they are similar in concept but differ in number of layers and how protocols fit within each model.
This document provides an overview of wireless networking standards and implementations. It describes how wireless networks use radio waves to communicate and follow the same OSI layers as wired networks. It outlines several IEEE 802.11 wireless standards including 802.11a, b, g, and n. It also discusses how Wi-Fi networks can operate in ad-hoc or infrastructure modes and how CSMA/CA is used to allow multiple devices to share the wireless medium. Finally, it covers common wireless security methods like MAC address filtering, wireless authentication, and data encryption using WEP.
This document provides an overview of different types of computer networks. It discusses local area networks (LANs) that connect computers within a confined geographic area like a building. It also discusses wide area networks (WANs) that combine multiple LANs across greater distances using technologies like phone lines. The document outlines two main categories of networks: peer-to-peer and server-based. It also provides a detailed explanation of the seven-layer OSI model and the functions of each layer, including the physical, data link, network, transport, session, presentation and application layers.
The document provides an overview of the seven-layer OSI model for computer networking. It describes each layer and its functions, including the physical, data link, network, transport, session, presentation and application layers. The physical layer defines cable specifications, the data link layer provides addressing and error detection, and the network layer enables routing between different networks using logical addresses. Higher layers include the transport layer for reliable data transmission, and the session, presentation and application layers for establishing communication between applications and presenting data to the end user.
This document provides an overview of the Open Systems Interconnection (OSI) model, which is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. It describes how data moves from one computer to another networked computer by dividing the tasks involved into 7 smaller layers, with each layer performing a specific communication task and providing services to adjacent layers to reduce complexity. The 7 layers are the physical, data link, network, transport, session, presentation, and application layers.
The OSI model is a reference model developed by ISO in 1984 for communication across different networks and applications. It defines the communication process into 7 layers, with layers 7 through 4 dealing with end-to-end communication and layers 3 through 1 dealing with communication between network devices. The 7 layers are: layer 7 application layer, layer 6 presentation layer, layer 5 session layer, layer 4 transport layer, layer 3 network layer, layer 2 data link layer, and layer 1 physical layer. Each layer has a specific function in the communication process.
The document discusses the Open Systems Interconnection (OSI) model, which defines seven layers for data communication between any two systems. The seven layers are the physical, data link, network, transport, session, presentation, and application layers. Each layer has a specific role, with the physical layer concerned with bit transmission and the application layer dealing with high-level services like email. The OSI model allows for flexible and robust network architecture design.
OSI Model - Open Systems InterconnectionAdeel Rasheed
The Open Systems Interconnection (OSI) reference model has served as the most basic elements of computer networking since the inception in 1984. The OSI Reference Model is based on a proposal developed by the International Standards Organization (ISO).
The document discusses the OSI model, which divides networking into 7 layers (physical, data link, network, transport, session, presentation, application) and standardizes network communication. It established the need for standards to ensure interoperability between different network implementations and describes the basic functions of each OSI layer and how data is encapsulated as it moves down the layers of the model.
The document discusses the OSI reference model, which defines 7 layers of network communication: physical, data link, network, transport, session, presentation, and application. Each layer has a specific role, such as the physical layer being responsible for transmitting raw bits over a communication medium and the network layer handling routing between devices. The layered approach separates network functionality and allows different aspects of communication to be developed independently.
7 Layers OSI model description with 3 unofficial Layers.Kanishk Raj
OSI reference model all seven layers description with 8,9,&10 not official layers that is also important in an organization ,when design the effective Network output.
The document discusses the OSI reference model, which is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. The OSI model structures network architecture into 7 layers, with each layer performing a specific set of functions. It defines the protocols used for communication between the layers of networked systems and allows networks to work together. The 7 layers are physical, data link, network, transport, session, presentation, and application layers. Each layer focuses on a specific task and provides services for the layer above it, hiding the details of its own implementation and the layers below it.
The document discusses the OSI model, which is a conceptual model that characterizes and standardizes the communication functions of a networking system without regard to their underlying internal structure and technology. It describes the seven layers of the OSI model from physical layer to application layer, and explains the functions of each layer, including physical addressing, framing, routing, error control, and providing services to applications. The layered architecture allows complete interoperability between different systems.
The OSI model is a standard reference model for network communication that consists of 7 layers:
1) The physical layer is responsible for the movements of individual bits from one hop to the next.
2) The data link layer is responsible for moving frames from one hop to the next.
3) The network layer is responsible for the delivery of individual packets from the source host to the destination host.
The OSI model divides network communication into 7 layers, with each layer building on the ones below it. The physical layer is responsible for physical interface and transmission, while the data link layer handles addressing and error checking. The network layer uses logical addressing to determine the best path for packet delivery. Higher layers include the transport layer, which segments data and ensures reliable delivery, as well as the session, presentation and application layers which handle user interactions. The OSI model provides a framework for designing networking hardware and software by standardizing the functions of each layer.
OSI (Open Systems Interconnection) is defined as reference model that is used for how applications can impart over the network. It is the conceptual model that is used for comprehension relationships. Copy the link given below and paste it in new browser window to get more information on OSI Model:- www.transtutors.com/homework-help/computer-science/osi-model.aspx
Osi Layer model provided by TopTechy.comVicky Kamboj
The document summarizes the Open Systems Interconnection (OSI) model, which describes how information is transferred between software applications running on different computers connected over a network. It explains that the OSI model defines 7 layers - physical, data link, network, transport, session, presentation and application layer - through which data passes as it travels from the source to destination. Each layer adds header information and communicates with its corresponding layer in the source/destination computer as well as with layers above and below it to successfully transfer information between applications across a network.
The document discusses the seven-layer Open Systems Interconnection (OSI) model for data communication between networked systems. It describes each layer of the OSI model including: the physical layer which deals with transmission and signaling of raw bit streams over a communication channel; the data link layer which transforms the physical layer into a reliable link; the network layer which is responsible for logical addressing and routing of packets across multiple networks; the transport layer which ensures complete and error-free delivery of message segments; the session layer which establishes and synchronizes interactions between systems; the presentation layer which formats data for transmission; and the application layer which provides user interfaces and services. Each layer uses the services of lower layers and provides services to higher layers.
The document discusses the 7 layers of the OSI model, with each layer adding headers or trailers to data as it passes through - the physical layer is the lowest layer dealing with transmission of raw data, followed by the data link layer, network layer, transport layer, session layer, presentation layer, and application layer as the highest layer of data exchange between applications.
The document describes the 7-layer OSI reference model developed by ISO in 1983 to standardize communication between systems and devices. It provides an overview of each layer, including the physical layer which defines electrical specifications, the data link layer which handles framing and error control, the network layer which performs routing between networks, the transport layer which provides reliable data transfer, the session layer which establishes connections, the presentation layer which translates between data formats, and the application layer which interacts directly with software applications. The model arranges the layers with each building upon the previous to standardize communication functions across different systems.
The document discusses network models including the OSI model and TCP/IP model. It describes the seven layers of the OSI model and the functions of each layer. It also discusses the four layers of the TCP/IP model and compares the two models, noting they are similar in concept but differ in number of layers and how protocols fit within each model.
This document provides an overview of wireless networking standards and implementations. It describes how wireless networks use radio waves to communicate and follow the same OSI layers as wired networks. It outlines several IEEE 802.11 wireless standards including 802.11a, b, g, and n. It also discusses how Wi-Fi networks can operate in ad-hoc or infrastructure modes and how CSMA/CA is used to allow multiple devices to share the wireless medium. Finally, it covers common wireless security methods like MAC address filtering, wireless authentication, and data encryption using WEP.
ISO is an organization which is established in 1947.
AN ISO standard that covers all aspects of network communication.
Network communication model is defined in OSI.
It was first introduced in the late 1970s, 1983
The document summarizes the seven layers of the OSI model:
1. The physical layer defines electrical specifications for activating and maintaining physical links.
2. The data link layer provides reliable transmission of data frames across physical links and defines media access control.
3. The network layer provides path selection and logical addressing between hosts across networks.
4. The transport layer segments data streams and handles flow control and reliability between hosts.
5. The session layer establishes and manages dialogues between presentation layers of two hosts.
6. The presentation layer ensures data formats are readable between applications of different systems.
7. The application layer provides network services to user applications like browsers and office programs.
This document provides an overview of Cisco router basics including the Cisco IOS, router components, boot sequence, configuration register, router interfaces, passwords, banners, hostname configuration, and commands for checking network connectivity such as ping and traceroute. It describes how to connect to routers via the console port or Telnet, use the command-line interface, and view configurations.
Pass4sures provides free trial for Cisco Specialist 100-101 exam (Cisco Exam). Before you come to a final decision whether you should be buying it or not, you must give it a try and find out if its interface, quality of the question and the productivity of our practice exams come up to your expectations.
The document discusses the OSI model layers that can be identified when packets are captured with Wireshark. At the datalink layer, MAC addresses will be shown; at the network layer, IP addresses will appear; the transport layer will display port details; and the application layer reveals the specific application, such as HTTP.
Routers are network devices that direct traffic between networks using hardware and software for path selection and packet switching. They perform functions like path selection, packet switching, broadcast containment, VLAN linking, and security/access control. Routers operate at the network edge connecting to WAN links and the internet, at the network core as the backbone, and anywhere for tasks like network segmentation and security. A hierarchical network design using routers reduces workload, constrains broadcasts, enhances simplicity and scaling.
This document discusses computer networks and networking concepts. It begins by defining what a computer network is and distinguishing between local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It then introduces the OSI model, which describes how systems communicate over a network through seven layers of abstraction. The document discusses each of the seven layers and provides examples. It also categorizes different types of connecting devices like repeaters, bridges, switches, and routers, and notes which OSI layers each operates in.
The document discusses media access control (MAC) protocols for wireless networks. It explains that standard MAC schemes from wired networks often fail in wireless scenarios due to signal attenuation over distance and the hidden terminal problem. It provides examples of the hidden terminal, exposed terminal, and near-far terminal problems that can occur in wireless networks. It then summarizes several MAC protocols used in wireless networks, including CSMA/CA, TDMA, FDMA, and ALOHA/Slotted ALOHA.
The document discusses the OSI model, which structures network communication into 7 layers - physical, data link, network, transport, session, presentation, and application. It provides an overview of the functions of each layer, from the physical layer which transmits raw data up to electrical signals, to the application layer which provides services for file transfers, printing and other applications. Diagrams and examples are included to illustrate how data moves through each layer of the OSI model during network communication.
This document provides an overview of network sniffing including definitions, vulnerable protocols, types of sniffing attacks, tools used for sniffing, and countermeasures. It discusses passive and active sniffing, ARP spoofing, MAC flooding, DNS poisoning techniques, and popular sniffing tools like Wireshark, Arpspoof, and Dsniff. It also outlines methods for detecting sniffing activity on a network such as monitoring for changed MAC addresses and unusual packets, as well as recommendations for implementing countermeasures like encryption, static ARP tables, port security, and intrusion detection systems.
The document provides an overview of the TCP/IP network model and how data is packaged and sent over a network, explaining that data moves through four layers (Application, Transport, Internet, Link) where it is encapsulated with headers at each layer, and that the Transport layer handles reliable transmission using TCP or unreliable transmission using UDP by adding a header and creating a TCP segment or datagram to pass to the Internet layer.
Comparison and Contrast between OSI and TCP/IP ModelConferencias FIST
The document compares the OSI and TCP/IP models.
- OSI has 7 layers including session and presentation layers, while TCP/IP combines their functions into its application layer.
- Both models have transport layers that provide reliable data transmission, with TCP/IP using TCP for connections and UDP for datagrams.
- The OSI network layer supports both connection-oriented and connectionless services, while TCP/IP's internet layer is solely connectionless using IP.
Distance vector routing is an algorithm where each node maintains a routing table with the distances to all other nodes and shares this table periodically with its neighbors. Nodes initially only know the cost to directly connected neighbors and update their tables based on information received, potentially leading to a "count to infinity" problem if routes oscillate. Solutions include using split horizon to not pass back the source of a route and poison reverse to mark such routes as infinite. RIP is an implementation of distance vector routing that shares updates every 30 seconds.
This document discusses packet sniffing and methods for detecting packet sniffers. It defines packet sniffing as monitoring all network packets and describes common packet sniffer tools like tcpdump. It explains that packet sniffers can be used for both legitimate and malicious purposes, such as password theft or network mapping. The document outlines two key methods for detecting packet sniffers - MAC detection and DNS detection. MAC detection works by sending packets with invalid MAC addresses and checking if any hosts respond in promiscuous mode. DNS detection exploits the behavior of sniffers performing DNS lookups on spoofed source IP addresses. Both methods were found to accurately detect the presence of packet sniffers on a network.
This document provides an introduction to routing and packet forwarding. It describes routers as computers that specialize in sending packets between networks by selecting the best path using routing tables. The document outlines router components, the boot-up process, interface types, and how routers examine packet headers to determine the best path and switch packets between incoming and outgoing interfaces. It also discusses topics like routing table structure, static and dynamic routing, path determination, and how packets are forwarded hop-by-hop between routers while headers are updated.
The document summarizes the seven layers of the OSI model:
1) Physical layer - responsible for establishing and terminating connections between nodes and media characteristics.
2) Data link layer - handles data transfer through framing and physical addressing.
3) Network layer - manages logical addressing and routing between networks.
4) Transport layer - ensures messages are delivered completely through connection control, flow control and error control.
5) Session layer - establishes and manages connections through dialog control and synchronization.
6) Presentation layer - manages data encryption/compression and translation during exchange.
7) Application layer - supports network applications through APIs and uses services from lower layers.
The document provides information about the OSI reference model, which is a framework for network communication consisting of 7 layers. Each layer defines a part of the process of moving information across a network, with higher layers building upon the services of lower layers. The physical layer is responsible for the physical transmission of bits across a network, while the data link layer handles frame transmission from node to node. The network layer is responsible for packet delivery across multiple networks by determining the optimal path.
2- lec_2.pptxDesigning with Type, SpacingDesigning with Type, SpacingDesignin...ZahouAmel1
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- The document describes the OSI seven-layer model and compares it to the TCP/IP model. It provides details on the functionality of each layer of the OSI model, including physical, data link, network, transport, session, presentation, and application layers. It also compares the four-layer TCP/IP model to the seven-layer OSI model, outlining similarities and differences between the two models.
The OSI model is a 7-layer framework for network communication created by ISO to standardize network design. Each layer has a specific purpose, such as physical transmission of bits, logical addressing, or application functions like email. Data moves down the layers during transmission, with each layer adding encapsulation headers so higher layer data can be transmitted reliably across networks.
OSI layers describes how the data can be send from one parties to another during data communication. it also gives the detailed information of how the data functionally divided into small pieces and reaches the destination.
The document provides an overview of the OSI model, which defines 7 layers of abstraction for characterizing and standardizing network communication functions. It describes each of the 7 layers, including the physical, data link, network, transport, session, presentation and application layers. The physical layer defines electrical specifications for devices and transmission mediums. Higher layers deal with issues like routing, congestion control, session establishment, data encoding and common application protocols. The OSI model aimed to standardize network architectures but TCP/IP is now more widely used.
The document discusses the seven layers of the OSI model:
1) The physical layer defines physical connections and transmission of raw bit streams.
2) The data link layer provides addressing and error checking for physical transmission between nodes.
3) The network layer establishes logical addressing for routing packets across multiple networks.
4) The transport layer provides end-to-end communication services between applications.
5) The session layer manages communication sessions, including synchronization and maintenance of sessions.
6) The presentation layer handles formatting and encryption of data for applications.
7) The application layer provides interfaces for end users and applications, such as web browsing and email.
This document provides an overview of the seven layers of the OSI model: Physical, Data Link, Network, Transport, Session, Presentation, and Application. It describes the key responsibilities and functions of each layer, such as the Physical layer defining electrical specifications, the Data Link layer providing node-to-node transfer, the Network layer transferring data between networks, and the Application layer directly interacting with software applications.
The document discusses the Open Systems Interconnection (OSI) model, which defines seven layers of network architecture - physical, data link, network, transport, session, presentation, and application. It describes the key functions of each layer, such as the physical layer dealing with physical connections and bits, the data link layer handling framing and addressing, and the application layer providing services to end users. The purpose of the OSI model is to facilitate communication between different computer systems by dividing the network communication process into standardized layers.
The document provides information about the CCNA certification options and Cisco networking concepts including the OSI model. It can be used to study for the CCNA exam. There are two options to obtain the CCNA: pass a single exam or two exams. The document then explains the OSI model in detail including mnemonics to remember the layer names and summaries of what occurs at each layer of the OSI model to help understand how data flows through a network.
The document provides an overview of the seven layers of the OSI model:
1) The physical layer defines physical connections and transmission of raw bit streams.
2) The data link layer provides addressing and error checking for data transmission between systems on a local network.
3) The network layer establishes logical addressing to route packets across multiple networks and provides fragmentation and reassembly of packets.
4) The transport layer offers reliable or unreliable data transmission and handles issues like flow control and multiplexing of data streams.
5) The session layer manages communication sessions, synchronizing data flow between endpoints.
The document provides an overview of Cisco's CCNA certification options and networking concepts including the OSI model. It discusses that Cisco offers a single exam or two exam option for CCNA certification. It then defines the OSI model layers and their purposes, with a focus on the lower layers including physical, data link and network layers. Sample exam questions are also provided related to the OSI model and protocols.
This Presentation consists of the detailed analysis of OSI & TCP/IP Model used for data transmission in Computer Network. It is very beneficial for any BTech, BCA, MCA, MTech students, or who is interested in networking field.
The document compares the OSI reference model and the TCP/IP model. The OSI reference model has 7 layers - physical, data link, network, transport, session, presentation and application layer. It was developed by ISO as a standard for network communication. The TCP/IP model has 4 layers - link, internet, transport and application layer. It is the communication protocol used for the internet and defines the rules for communication between computers over the internet. TCP and IP work together, with TCP handling communication between applications and networks, and IP handling communication between computers.
This document provides information on networking concepts including wireless networks, the ISO-OSI 7 layer model, and TCP/IP model. It describes each layer of the OSI model in 1-2 sentences, including the physical, data link, network, transport, session, presentation, and application layers. It also briefly defines the TCP/IP layers of application, transport, network, and data link.
The OSI reference model is a standardized framework for network architecture that consists of 7 layers: physical, data link, network, transport, session, presentation, and application. Each layer defines a part of the process of moving information across a network and works together with adjacent layers to provide a unified quality of service. Data moves down through the layers on the sending system and is encapsulated with headers and trailers at each layer before being transmitted. At the receiving system, the reverse process occurs as headers are removed and data is de-encapsulated moving up the layers.
The document discusses network models including the OSI model and TCP/IP model. It describes the seven layers of the OSI model and the four layers of the TCP/IP model. For each layer, it provides details on their functions and protocols. It also compares the OSI and TCP/IP models, noting they are both based on layered architectures but that the TCP/IP model combines some layers and better fits existing protocols.
The document discusses the OSI model, which is a standard framework for network communication. It divides network architecture into seven layers: physical, data link, network, transport, session, presentation, and application. Each layer only communicates with the layers directly above and below it and has a specific set of functions. This layered approach makes networks easier to design, troubleshoot, and maintain when changes are made. The physical layer deals with physical connections and bit transmission. The data link layer organizes bits into frames and controls flow. The network layer decides how data moves between networks. Higher layers ensure reliable and secure delivery of data between applications.
The document provides information about CCNA certification options and the OSI model. It discusses two options for obtaining the CCNA certification, recommends taking a single exam, and includes a table listing common network device icons. It then covers the seven layers of the OSI model in detail, providing descriptions, examples, and review questions for each layer. Finally, it discusses the TCP/IP protocol suite and compares it to the OSI model, listing several example protocols like FTP, TFTP, and HTTP.
The document discusses network management topics including access lists, Cisco IOS software, backing up configurations and software, and Cisco Discovery Protocol. It describes how access lists filter packets, the differences between standard and extended lists, and how to apply lists. It also explains how to load IOS software, back up configurations and software, and restore them. Finally, it provides details on Cisco Discovery Protocol and how it helps collect device information.
This document discusses various WAN protocols including Frame Relay, ISDN, HDLC, PPP, and DDR. Frame Relay is a packet-switched protocol that uses DLCIs and LMI frames. ISDN provides digital telephony and data services. HDLC is a data link protocol that specifies encapsulation. PPP is used for dial-up connections and supports authentication. DDR allows routers to dial an ISDN connection on demand.
The document discusses routing protocols and concepts. It explains that routing is the act of moving information across an internetwork from source to destination. It then discusses different types of routing protocols including interior gateway protocols like RIP, IGRP, EIGRP, and OSPF, as well as exterior protocols. The document also covers routing fundamentals and how to configure and verify routing on Cisco routers.
This document discusses IP addressing and routing protocols. It begins by explaining IP addressing, including the components of an IP address. It then covers number systems like decimal, binary, and hexadecimal and how to convert between them. The document also discusses classes of IP addresses, network masks, subnetting, and configuring and troubleshooting IP addresses. Finally, it lists several TCP/IP application layer protocols like FTP, SMTP, SNMP, and DHCP.
Routers route data between networks and come in either hardware or software forms. Hardware routers are physical boxes that run vendor software for routing, while software routers use network servers like NT or Linux to route traffic but don't have dedicated boxes. Routers contain interfaces, a CPU, IOS operating system, RAM, NVRAM, ROM, and flash memory. They operate in different modes like setup, user exec, privileged exec, and global configuration to perform functions like configuring interfaces.
This document discusses bridging and switching concepts, including:
- Bridges connect network segments at layer 2 and forward frames based on MAC addresses. Switches are hardware-based bridges that provide higher performance.
- Switches learn MAC addresses, make forwarding/filtering decisions, and avoid loops using protocols like STP. They can operate in cut-through, fragment-free, or store-and-forward modes.
- Configuring a switch involves setting passwords, the hostname, IP information, interface settings, and protocols like STP, VLANs, and VTP to extend VLANs across switches.
This document discusses various LAN technologies including Ethernet, LocalTalk, Token Ring, and FDDI. It covers LAN transmission methods like unicast, multicast, and broadcast. Common LAN topologies such as bus, ring, star, and tree are explained. Media access methods including CSMA/CD and token passing are outlined. Finally, common cabling types for LANs such as twisted pair, coaxial, and fiber optic cables are described.
A network consists of two or more connected computers that share resources. There are three main types of networks: local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). LANs are confined to a small area like a building or office. MANs cover larger areas like cities. WANs connect even larger geographic areas spanning hundreds or thousands of kilometers.
This document provides information about Cisco Network Administration software released on May 12, 2004. The product number is 06.02.2.3.1.01 and the version number is 1.0.0.0. It was released by an IT partner company.
2. Objectives
• Understand OSI model
• Explain the principle applied to arrive at seven layers.
• Explain the advantage of dividing network into layers.
• Explain the characteristics of the OSI layers.
• Understand how communication done between
systems using the OSI model.
• Explain different networking devices used in the OSI
layer.
• Understand TCP/IP stack.
• Explain connectionless and connection oriented
services.
• Understand Windowing
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3. Introduction
OSI reference model:
• Describes how information from a software
application in one computer moves through a network
medium to a software application in anther computer.
• Conceptual model composed of seven layers, each
specifying particular network functions. Each layer is
reasonably self-contained so that the functions
assigned to each layer can be implemented
independently.
• Developed by the International Standards
Organization (ISO) as a first step toward international
standardization of the protocols used in various layers
in 1983.
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4. Introduction contd..
The principles that were applied to arrive at the seven
layers are as follows:
• A layer should be created where a different level of
abstraction is needed.
• Each layer should perform a well-defined function.
• The function of each layer should be chosen with an
eye toward defining internationally standardized
protocols.
• The layer boundaries should be chosen to minimize the
information flow across the interfaces.
• The number of layers should be large enough that
distinct functions need not be thrown together in the
same layer out of necessity, and small enough that the
architecture does not become unwieldy.
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5. Introduction contd..
The seven layers of the OSI model are numbered from
bottom to top as follows:
7 Application
6 Presentation
5 Session
4 Transport
3 Network
2 Data link
1 Physical
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6. Characteristics of the OSI Layers
The main characteristics of the seven layers OSI model are:
• Each layer performs a defined subset of functions
for the overall communication process
• To perform more primitive functions
• To hide the details of the lower layer functions
• Each layer provides services to the next higher
layer
• Modifications within a layer do not require
modifications of the other layers
• Dividing the communication functions into separate
layers facilitates the management of the
communication process.
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7. Characteristics of the OSI Layers contd..
The seven layers of the OSI reference model can be divided
into two categories:
• Upper Layers: Deal with application issues and
generally implemented only in software.
• Lower Layers: Handle data transport issues.
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8. Advantages of Dividing Network into
Layers
• Divides the interrelated aspects of network operation
into less complex elements.
• Defines standard interfaces for plug-and-play
compatibility and multi-vendor integration.
• Enables engineers to specialize design and promote
symmetry in the different internetwork modular functions
so that they interoperate.
• Prevents changes in one area from affecting other
areas, so each area can evolve more quickly
• Divides the complexity of internetworking into discrete,
more easily learned operation subsets.
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9. The Seven OSI Reference Model Layers
Physical Layer (Layer 1)
• The physical layer is concerned with transmission of
unstructured bit stream over physical link; involves such
parameters as signal voltage swing and bit duration.
• It accepts frames of data from the upper layer, the Data
Link Layer (Layer 2) and transmits the data serially, one
bit at a time.
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10. The Seven OSI Reference Model Layers contd..
Data Link Layer (Layer 2)
• The data link layer provides reliable transfer of data
across the physical link. It sends blocks of data (frames)
with the necessary synchronization, error control and
flow control.
• It exchanges a "frame" with Data Link Layer on another
node.
• The Data Link Layer provides services to the Network
Layer above. It receives the data from layer 3 and adds
the necessary control information, and sends it to the
layer 1 as a frame. It also verifies the frame received
from layer 1 and ensures the acknowledgement and
sends the data up to the layer 3.
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11. Data Link Layer (Layer 2) contd..
The Data Link layer contains two sub-layers:
• Logical Link Control (LLC): This sublayer is
responsible for identifying Network layer protocols and
then encapsulating them. An LLC header tells the Data
Link layer what to do with a packet once a frame is
received.
• Media Access Control (MAC): This defines how
packets are placed on the media. Contention media
access is “first cum first served” access where everyone
shares the same bandwidth. Physical addressing is
defined here, as well as logical topologies.
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12. The Seven OSI Reference Model Layers contd..
Network Layer (Layer 3)
The Network layer manages device addressing, tracks the
location of devices on the network and determines the best
way to move data.
Routers (layer 3 devices) are specified at the Network layer
and provide the routing services within an internetwork.
Two types of packets are used at the Network layer:
• Data Packets: It is used to transport user data through
the internetwork.
• Route Update Packets: It is used to update neighboring
routers about the networks connected to all routers
within the internetwork.
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13. The Seven OSI Reference Model Layers contd..
Transport Layer (Layer 4)
The transport layer accepts data from the session layer and
segments the data for transport across the network. This
layer is responsible for making sure that the data is
delivered error-free and in the proper sequence.
Flow Control: Data integrity is ensured at the Transport
layer by maintaining flow control and by allowing users to
request reliable data transport between systems.
Multiplexing enables data from several applications to be
transmitted onto a single physical link
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14. Transport Layer (Layer 4) contd..
Reliable data transport employs a connection-oriented
communications session between systems, and the
protocols involved ensure that the following will be
achieved:
• The segments delivered are acknowledged back to the
sender upon their reception.
• Any segments not acknowledged are retransmitted.
• Segments are sequenced back into their proper order
upon arrival at their destination.
• A manageable data flow is maintained in order to avoid
congestion, overloading, and data loss.
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15. The Seven OSI Reference Model Layers contd..
Session Layer (Layer 5)
The main function of the OSI model's session layer is to
control "sessions", which are logical connections between
network devices.
This layer provides dialogue control between devices, or
nodes. It coordinates communication between systems and
serves to organize their communication by offering three
different modes:
• Simplex
• Half duplex
• Full duplex
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16. The Seven OSI Reference Model Layers contd..
Presentation Layer (Layer 6)
It presents data to the Application layer. It's basically a
translator and provides coding and conversion functions.
By providing translation services, the Presentation layer
ensures that data transferred from the Application layer of
one system can be read by the Application layer of another
host.
Tasks like data compression, decompression, encryption
and decryption are associated with this layer.
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17. Presentation Layer (Layer 6) contd..
Some Presentation layer standards are involved in
multimedia operations. The following serve to direct graphic
and visual image presentation:
• JPEG: The Joint Photographic Experts Group brings
these photo standards.
• MIDI: The Musical Instrument Digital Interface is used
for digitized music.
• MPEG: The Moving Pictures Experts Group's standard
for the compression and coding of motion video for CD's
is very popular.
• QuickTime: This is for use with Machintosh or Power
PC programs, it manages audio and video applications.
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18. The Seven OSI Reference Model Layers contd..
Application Layer (Layer 7)
The application layer is the OSI layer closest to the end
user, which means that both the OSI application layer and
the user interact directly with the software application.
Application layer functions typically include identifying
communication partners, determining resource availability
and synchronizing communication.
Some examples of application layer implementations
include Telnet, File Transfer Protocol (FTP) and Simple Mail
Transfer Protocol (SMTP).
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19. Communication between Systems
using the OSI Model
Information being transferred from a software application in
one computer system to a software application in another
must pass through the OSI layers.
A given layer in the OSI model generally communicates with
three other OSI layers: System X System Y
• layer directly above it Application Application
• layer directly below it Presentation Presentation
• its peer layer in other Session Session
networked computer Transport Transport
systems Network Network
Data link Data link
Physical Physical
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20. Communication between Systems using the OSI Model contd..
How data is transmitted using the OSI model
System X System Y
Sending Receiving
Process Process
Data
Application Application
Application Protocol AH Data
Layer Layer
Presentation Presentation
Layer Presentation Protocol PH Data Unit Layer
Session Layer Session Layer
Session Protocol SH Data Unit
Transport Layer Transport Layer
Transport Protocol TH Data Unit
Network Layer Network Network Layer
NH Data Unit
Protocol
Data link Layer DH Data Unit DT Data link Layer
Physical Layer Physical Layer
Bits
Network
Actual data transmission path
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21. Communication between Systems using the OSI Model contd..
Encapsulation
As data travels down the layer stack at the sending system,
each layer adds a header to the front of it and gives the
resulting item to the lower layer. Some layer also adds a trailer
to the rear of the data unit. This addition of a header/trailer to
the higher layer data unit is called encapsulation.
De-encapsulation
As data travels upward the layer stack at the receiving system,
the layer reads the header from its peer layer, strips it off, and
passes the remaining information unit to the next highest layer.
This is known as de-encapsulation.
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22. More on Encapsulation
There are five steps of encapsulation:
1. User information is converted into data.
2. Data is converted into segments for transport
across the network.
3. Segments are converted into packets.
4. Packets and datagrams are converted into
frames and the Data Link header is added.
5. The data in the frames is converted into bits for
transmission over the physical media.
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23. More on Encapsulation contd..
The following table describes data encapsulation by OSI
layer:
OSI Layer Encapsulation
Transport Segment
Network Packet
Data Link Frame
Physical Bits
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24. Networking Devices to their OSI Layer
Physical Layer: Repeater, Hub, Network interface card (NIC
card)
• Repeater: A repeater is a network device. The main
function of repeater is to regenerate a single to allow it
to travel greater distances along a network.
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25. Networking Devices to their OSI Layer contd..
• HUB: It operates at the Physical layer of the OSI
model. HUB does not have any processing power, it's
just a box where you plug cables.
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26. Networking Devices to their OSI Layer contd..
• NIC: Puts the data into packets and transmits packet
onto the network. Every NIC card has a unique address
burnt into the card. This address is in a flat
hexadecimal number.
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27. Networking Devices to their OSI Layer contd..
Data Link Layer: Switches, Bridges
• Switch: Switch acts like a hub, but unlike the hub it
examines the destination MAC (Media Access Control)
addresses of the packet to decide where the packet
should be forwarded.
• Bridge: Bridges segments a network and reduce
network traffic by examining the source and destination
hardware address of the packet.
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28. Networking Devices to their OSI Layer contd..
Network Layer: Routers
• Routers: Devices at the Network layer are concerned
with two main things – network addressing and routing.
Routers reduce broadcast storms because they don't
route broadcast packets.
Cisco 1600 and 2500 Series Router
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29. Differences between Data Link and
Network Addresses
Data Link addresses (Data-link layer) are for the most part
referred to as flat address space unique addresses.
We mostly relate them to the term physical or hardware
addressing.
Example Address: 00-AA-BB-CC-DD-EE (MAC Address)
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30. Differences between Data Link and Network Addresses contd..
Network Addresses (Network Layer) are logical addresses
that are used for path selection, route determination and
selection.
Example Address: 192.168.100.2 where 192.168.100 is the
network and 2 is the individual host ID
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31. OSI Model and TCP/IP Stack
OSI Model Layers TCP/IP Protocol Architecture Layers TCP/IP Protocol Suite
Application Layer
FTP
HTTP
Presentation Layer Application Layer SMTP
SNMP
TELNET
Session Layer
Transport Layer Host-to-Host Transport Layer TCP UDP
Network Layer Internet Layer IP
ARP RARP ICMP
Data link Layer Ethernet
Fast Ethernet
Network Interface Layer Token Ring
Physical Layer FDDI
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32. OSI Model and TCP/IP Stack contd..
TCP/IP Protocol Suite
TCP/IP makes it possible for two computers, which are part
of different networks (connected by routers or gateways) to
exchange data.
Different protocols of TCP/IP suite:
• Application protocols occupy the highest protocol
layers and provide specific services.
• TCP (Transfer Control Protocol) and UDP (User
Datagram Protocol) facilitate the transmission of data
streams between applications running on different hosts.
• IP (Internet Protocol), a lower-level protocol than TCP
or UDP, governs the transmission of data packets
throughout a computer network.
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33. TCP/IP Protocol Suite contd..
Application Protocols:
• FTP (File Transfer Protocol)
• HTTP (Hypertext Transfer Protocol)
• SMTP (Simple Mail Transfer Protocol)
• SNMP (Simple Network Management Protocol)
• NNTP (Network News Transfer Protocol)
• Telnet
• WAP (Wireless Application Protocol)
Network layer protocols, that are less visible but play
equally important roles in TCP/IP networks, include:
• ARP (Address Resolution Protocol)
• RARP (Reverse Address Resolution Protocol)
• ICMP (Internet Control Message Protocol)
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34. Connection-Oriented and Connectionless
Services
Connection-oriented means that a connection (a virtual
link) must be established before data can be exchanged. In
connection-oriented service the source first informs the
network it wishes to start a conversation with destination,
the network sends it's request to the destination that
accepts or rejects the request. If the destination refuses,
connection fails, otherwise connection is established.
The communication proceeds through three well-defined
phases:
• Connection establishment
• Data transfer
• Connection release
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35. Connection-Oriented and Connectionless Services contd..
A typical reliable session taking place between sending and
receiving systems.
Sender Receiver
Synchronize
Negotiate Connection
Synchronize
Acknowledge
Connection Established
Data Transfer
(Send segments)
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36. Connection-Oriented and Connectionless Services contd..
Connectionless is the opposite of connection-oriented.
The sender does not establish a connection before it sends
data, it just sends without guaranteeing delivery. Packets
sent between two hosts may take different routes. UDP is
an example of a connectionless transport protocol.
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37. Windowing
The quantity of data segments (measured in bytes) the
transmitting machine is allowed to send without receiving an
acknowledgment for them is called a window.
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