The document discusses the ISO-OSI 7-layer reference model and related IEEE standards. It covers the purpose and functions of each layer, including the physical, data link, network, transport, session, presentation and application layers. It also describes how data is formatted and encapsulated as it passes through each layer. Finally, it discusses the IEEE 802 standards group and some of the key standards they developed that apply to networking, particularly at the data link and physical layers.
This document discusses the ISO-OSI 7-layer reference model and related IEEE standards. It provides an overview of the ISO-OSI model, describing the 7 layers and their functions. It also describes some of the major IEEE 802 committees and their responsibilities in setting standards related to the lower two OSI layers of data link and physical. These standards apply to areas like network cards, cables, and wireless communication protocols.
The document describes the OSI model and TCP/IP model. It explains:
- The OSI model has 7 layers (physical, data link, network, transport, session, presentation, application) while TCP/IP has 4 layers (network interface, internet, transport, application).
- The transport layer in TCP/IP includes TCP and UDP protocols which handle segmentation and reassembly of data.
- The network layer adds headers to data segments and handles addressing and routing between hosts using IP addresses.
- The data link and physical layers in OSI correspond to the network interface layer in TCP/IP, which deals with framing data and transmitting bits.
This document discusses the ISO-OSI 7-layer reference model and related IEEE standards. It provides an overview of the ISO-OSI model, describing the 7 layers and their functions. It also describes some of the major IEEE 802 committees and their responsibilities in setting standards related to the lower two OSI layers of data link and physical. These standards apply to areas like network cards, cables, and wireless communication protocols.
ET3003-2 OSI-TCPIP (Semester II 2013-2014)Tutun Juhana
The document provides an overview of the OSI model and TCP/IP protocol suite for computer networks. It discusses that while the OSI model was intended as a standard, TCP/IP became the dominant model used on the internet. It then describes each layer of the OSI model and its functions. It also summarizes the layers of the TCP/IP protocol suite and how they compare to the OSI layers. Key areas like addressing, encapsulation, and the roles of different address types are also summarized.
This document discusses network protocol architectures and reference models. It begins by explaining the need for a protocol architecture to break communication tasks into modular layers. It then describes the two main protocol architectures: TCP/IP and the OSI model. The TCP/IP architecture organizes communication into 5 layers - physical, data link, internet, transport, and application. It relies primarily on IP for internet layer functions and TCP and UDP for transport layer functions. The OSI model also divides communication into 7 layers for interoperability between different systems.
The document discusses the TCP/IP and OSI networking models. It introduces the TCP/IP model, which was developed in 1978 and forms network communication into seven layers. It then describes the OSI model, which was developed by the International Organization for Standardization (ISO) and breaks network functions into seven layers. The layers of both models are explained, with the lower layers handling physical transmission and higher layers providing services to applications. The OSI model is now more commonly used as a standard for network design.
The document describes the 7 layers of the OSI model. Each layer has a specific function: Physical layer handles transmission of raw bits of data; Data link layer organizes bits into frames and handles node-to-node delivery; Network layer handles packet transmission between hosts and logical addressing; Transport layer ensures reliable end-to-end communication through techniques like segmentation and error control; Session layer establishes and manages communication sessions between applications; Presentation layer defines data presentation formats and handles things like encryption and compression; Application layer allows direct user interaction with applications and network resources.
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
This document discusses the ISO-OSI 7-layer reference model and related IEEE standards. It provides an overview of the ISO-OSI model, describing the 7 layers and their functions. It also describes some of the major IEEE 802 committees and their responsibilities in setting standards related to the lower two OSI layers of data link and physical. These standards apply to areas like network cards, cables, and wireless communication protocols.
The document describes the OSI model and TCP/IP model. It explains:
- The OSI model has 7 layers (physical, data link, network, transport, session, presentation, application) while TCP/IP has 4 layers (network interface, internet, transport, application).
- The transport layer in TCP/IP includes TCP and UDP protocols which handle segmentation and reassembly of data.
- The network layer adds headers to data segments and handles addressing and routing between hosts using IP addresses.
- The data link and physical layers in OSI correspond to the network interface layer in TCP/IP, which deals with framing data and transmitting bits.
This document discusses the ISO-OSI 7-layer reference model and related IEEE standards. It provides an overview of the ISO-OSI model, describing the 7 layers and their functions. It also describes some of the major IEEE 802 committees and their responsibilities in setting standards related to the lower two OSI layers of data link and physical. These standards apply to areas like network cards, cables, and wireless communication protocols.
ET3003-2 OSI-TCPIP (Semester II 2013-2014)Tutun Juhana
The document provides an overview of the OSI model and TCP/IP protocol suite for computer networks. It discusses that while the OSI model was intended as a standard, TCP/IP became the dominant model used on the internet. It then describes each layer of the OSI model and its functions. It also summarizes the layers of the TCP/IP protocol suite and how they compare to the OSI layers. Key areas like addressing, encapsulation, and the roles of different address types are also summarized.
This document discusses network protocol architectures and reference models. It begins by explaining the need for a protocol architecture to break communication tasks into modular layers. It then describes the two main protocol architectures: TCP/IP and the OSI model. The TCP/IP architecture organizes communication into 5 layers - physical, data link, internet, transport, and application. It relies primarily on IP for internet layer functions and TCP and UDP for transport layer functions. The OSI model also divides communication into 7 layers for interoperability between different systems.
The document discusses the TCP/IP and OSI networking models. It introduces the TCP/IP model, which was developed in 1978 and forms network communication into seven layers. It then describes the OSI model, which was developed by the International Organization for Standardization (ISO) and breaks network functions into seven layers. The layers of both models are explained, with the lower layers handling physical transmission and higher layers providing services to applications. The OSI model is now more commonly used as a standard for network design.
The document describes the 7 layers of the OSI model. Each layer has a specific function: Physical layer handles transmission of raw bits of data; Data link layer organizes bits into frames and handles node-to-node delivery; Network layer handles packet transmission between hosts and logical addressing; Transport layer ensures reliable end-to-end communication through techniques like segmentation and error control; Session layer establishes and manages communication sessions between applications; Presentation layer defines data presentation formats and handles things like encryption and compression; Application layer allows direct user interaction with applications and network resources.
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
Computer network : models and topologiesAnup Pandey
The document provides an overview of computer networks, including transmission modes, network types, protocols, models (OSI and TCP/IP), and topologies. It describes point-to-point, broadcasting and multicasting transmission modes. Local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs) are discussed. The seven layer OSI model and five layer TCP/IP model are compared. Common network topologies including bus, star, ring, mesh and tree are also summarized.
The document discusses network layer models including the OSI model and TCP/IP model. It provides details on each layer of the models and their functions. The OSI model has 7 layers - physical, data link, network, transport, session, presentation and application. The TCP/IP model combines some of these layers and has 5 layers - physical, data link, network, transport and application. Each layer is responsible for distinct networking functions and passes messages to the adjacent layers for delivery. [/SUMMARY]
This document discusses protocol layering in communication networks. It introduces the need for protocol layering when communication becomes complex. Protocol layering involves dividing communication tasks across different layers, with each layer having its own protocol. The document then discusses two principles of protocol layering: 1) each layer must support bidirectional communication and 2) the objects under each layer must be identical at both sites. It provides an overview of the OSI 7-layer model and describes the basic functions of each layer.
This document is an introduction to computer science networks lecture that describes the seven-layer OSI networking model. It explains the specific functionality of each layer and how different network devices and software operate at certain layers. The layers include the physical, data link, network, transport, session, presentation, and application layers. The document also provides examples of how network communication works from an email being sent and how medical devices adhere to standards like OSI when transmitting data.
The document discusses the seven layers of the Open Systems Interconnection (OSI) model, with a focus on the physical and data link layers. It describes the key responsibilities of the physical layer, including representing bits, synchronizing data transmission, defining transmission media and topology. It also outlines the major duties of the data link layer, such as framing data, implementing addressing, and handling errors.
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 discusses the OSI reference model, which was developed by ISO in 1984 to standardize network communication. It describes the need for standards due to incompatible networks. The OSI model organizes network functions into seven layers, with each layer providing services to the layer above and handling distinct network duties like physical transmission, routing, and application support. This layered approach reduces complexity and promotes interoperability between different network technologies.
This document discusses the functions, vulnerabilities, and controls at each layer of the OSI model:
1. Physical layer: deals with physical addressing and network topology. Vulnerabilities include eavesdropping and physical theft. Controls include locks, surveillance and electromagnetic shielding.
2. Data link layer: deals with MAC addressing and frame ordering. Vulnerabilities are MAC spoofing and VLAN issues. Controls include MAC filtering and secure VLAN design.
3. Network layer: deals with routing and path determination. Vulnerabilities are route and IP spoofing. Controls include route filtering and firewalls.
4. Transport layer: deals with multiplexing, sequencing and error checking. Vulnerabilities are spoofing and protocol differences
OSI Reference Model - internationally standardised network architecture.
OSI = Open Systems Interconnection: deals with open systems, i.e.systems open for communications with other systems.
Specified in ISO 7498.
Model has 7 layers.
The document provides an overview of the OSI model layers and their associated protocols. It discusses the seven layers of the OSI model from physical to application layer. For each layer, it describes the main functions and examples of protocols used. Key points covered include physical layer components like cabling, data link layer protocols like Ethernet, switches and spanning tree, network layer addressing and routing, transport layer protocols TCP and UDP, and wireless network security standards.
The document discusses various networking standards organizations and the OSI model. It describes organizations that set standards like ANSI, IEEE, ISO, IETF, and ICANN. It then explains the seven-layer OSI model and provides a brief overview of the functions of each layer, from the physical layer dealing with signals and voltages, to the application layer that applications use.
The document discusses network models and protocol layering. It describes the TCP/IP model which consists of five layers - application, transport, network, data link, and physical. It also mentions the OSI model. Each layer in the TCP/IP model has specific responsibilities like the application layer supporting network applications, the transport layer handling end-to-end data transfer, the network layer routing data, the data link layer transferring data between neighboring elements, and the physical layer dealing with transmission of raw bits. Layering allows for modularity and abstraction which helps manage network complexity.
The document discusses the OSI Reference Model, which divides networking functions into 7 layers - physical, data link, network, transport, session, presentation, and application layer. Each layer has distinct responsibilities and provides services to the layer above it. The model was developed by ISO to standardize network communication and ensure compatibility between different systems.
The document discusses the OSI model, which is a conceptual model for networking that standardizes communication functions without regard to the underlying technology. It partitions communication systems into 7 abstraction layers, with each layer serving the layer above it. Layer 1 is the physical layer that transmits raw data over a medium. Layer 2 is the data link layer that provides node-to-node transfer and error correction. Layer 3 is the network layer that transfers variable length packets between different networks and can route messages through intermediate nodes.
This document provides information on layering in networked computing by discussing the OSI and TCP/IP models. It begins by outlining the learning objectives, which are to understand the need for layering, the layers and protocols in each model, and how data is transmitted between layers and hosts. It then describes each layer in the OSI model and its functions. The TCP/IP model is also explained, comparing it to the OSI model by mapping its 4 layers to the 7 layers of OSI. Key protocols at each layer are identified and packet encapsulation in TCP/IP is demonstrated.
This document provides an overview of computer networks and networking concepts. It discusses the OSI model and its seven layers, including the responsibilities of each layer. It also describes the TCP/IP protocol suite and how it maps to the OSI model. Physical network topologies like star, bus, ring and mesh are defined. The document examines addressing in TCP/IP networks, including physical, logical, and port addresses. Network devices, protocols, and the exchange of data across the OSI model layers are summarized as well.
Get custom writing services for OSI Model Assignment help & OSI Model Homework help. Our OSI Model Online tutors are available for instant help for OSI Model assignments & problems.OSI Model Homework help & OSI Model tutors offer 24*7 services . Send your OSI Model assignments at support@globalwebtutors.com or else upload it on the website. Instant Connect to us on live chat for OSI Model assignment help & OSI Model Homework help.
This document discusses the ISO-OSI 7-layer reference model and related IEEE standards for network communications. It provides an overview of the ISO and its 7-layer OSI model, describing each layer's function and how layers communicate with each other. It also discusses how the IEEE 802 group sets standards for the data link and physical layers, including specific standards for common network types like Ethernet, Token Ring, wireless, etc. The overall purpose is to explain the layered network communication model and standards that enable interoperability.
The document provides information about the OSI model and TCP/IP reference model. It describes the seven layers of the OSI model from the physical layer to the application layer and summarizes the responsibilities of each layer. It then compares the OSI model to the TCP/IP reference model, noting their similarities like layered architecture and application layers, as well as differences such as TCP/IP combining layers and being more simplified.
Computer network : models and topologiesAnup Pandey
The document provides an overview of computer networks, including transmission modes, network types, protocols, models (OSI and TCP/IP), and topologies. It describes point-to-point, broadcasting and multicasting transmission modes. Local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs) are discussed. The seven layer OSI model and five layer TCP/IP model are compared. Common network topologies including bus, star, ring, mesh and tree are also summarized.
The document discusses network layer models including the OSI model and TCP/IP model. It provides details on each layer of the models and their functions. The OSI model has 7 layers - physical, data link, network, transport, session, presentation and application. The TCP/IP model combines some of these layers and has 5 layers - physical, data link, network, transport and application. Each layer is responsible for distinct networking functions and passes messages to the adjacent layers for delivery. [/SUMMARY]
This document discusses protocol layering in communication networks. It introduces the need for protocol layering when communication becomes complex. Protocol layering involves dividing communication tasks across different layers, with each layer having its own protocol. The document then discusses two principles of protocol layering: 1) each layer must support bidirectional communication and 2) the objects under each layer must be identical at both sites. It provides an overview of the OSI 7-layer model and describes the basic functions of each layer.
This document is an introduction to computer science networks lecture that describes the seven-layer OSI networking model. It explains the specific functionality of each layer and how different network devices and software operate at certain layers. The layers include the physical, data link, network, transport, session, presentation, and application layers. The document also provides examples of how network communication works from an email being sent and how medical devices adhere to standards like OSI when transmitting data.
The document discusses the seven layers of the Open Systems Interconnection (OSI) model, with a focus on the physical and data link layers. It describes the key responsibilities of the physical layer, including representing bits, synchronizing data transmission, defining transmission media and topology. It also outlines the major duties of the data link layer, such as framing data, implementing addressing, and handling errors.
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 discusses the OSI reference model, which was developed by ISO in 1984 to standardize network communication. It describes the need for standards due to incompatible networks. The OSI model organizes network functions into seven layers, with each layer providing services to the layer above and handling distinct network duties like physical transmission, routing, and application support. This layered approach reduces complexity and promotes interoperability between different network technologies.
This document discusses the functions, vulnerabilities, and controls at each layer of the OSI model:
1. Physical layer: deals with physical addressing and network topology. Vulnerabilities include eavesdropping and physical theft. Controls include locks, surveillance and electromagnetic shielding.
2. Data link layer: deals with MAC addressing and frame ordering. Vulnerabilities are MAC spoofing and VLAN issues. Controls include MAC filtering and secure VLAN design.
3. Network layer: deals with routing and path determination. Vulnerabilities are route and IP spoofing. Controls include route filtering and firewalls.
4. Transport layer: deals with multiplexing, sequencing and error checking. Vulnerabilities are spoofing and protocol differences
OSI Reference Model - internationally standardised network architecture.
OSI = Open Systems Interconnection: deals with open systems, i.e.systems open for communications with other systems.
Specified in ISO 7498.
Model has 7 layers.
The document provides an overview of the OSI model layers and their associated protocols. It discusses the seven layers of the OSI model from physical to application layer. For each layer, it describes the main functions and examples of protocols used. Key points covered include physical layer components like cabling, data link layer protocols like Ethernet, switches and spanning tree, network layer addressing and routing, transport layer protocols TCP and UDP, and wireless network security standards.
The document discusses various networking standards organizations and the OSI model. It describes organizations that set standards like ANSI, IEEE, ISO, IETF, and ICANN. It then explains the seven-layer OSI model and provides a brief overview of the functions of each layer, from the physical layer dealing with signals and voltages, to the application layer that applications use.
The document discusses network models and protocol layering. It describes the TCP/IP model which consists of five layers - application, transport, network, data link, and physical. It also mentions the OSI model. Each layer in the TCP/IP model has specific responsibilities like the application layer supporting network applications, the transport layer handling end-to-end data transfer, the network layer routing data, the data link layer transferring data between neighboring elements, and the physical layer dealing with transmission of raw bits. Layering allows for modularity and abstraction which helps manage network complexity.
The document discusses the OSI Reference Model, which divides networking functions into 7 layers - physical, data link, network, transport, session, presentation, and application layer. Each layer has distinct responsibilities and provides services to the layer above it. The model was developed by ISO to standardize network communication and ensure compatibility between different systems.
The document discusses the OSI model, which is a conceptual model for networking that standardizes communication functions without regard to the underlying technology. It partitions communication systems into 7 abstraction layers, with each layer serving the layer above it. Layer 1 is the physical layer that transmits raw data over a medium. Layer 2 is the data link layer that provides node-to-node transfer and error correction. Layer 3 is the network layer that transfers variable length packets between different networks and can route messages through intermediate nodes.
This document provides information on layering in networked computing by discussing the OSI and TCP/IP models. It begins by outlining the learning objectives, which are to understand the need for layering, the layers and protocols in each model, and how data is transmitted between layers and hosts. It then describes each layer in the OSI model and its functions. The TCP/IP model is also explained, comparing it to the OSI model by mapping its 4 layers to the 7 layers of OSI. Key protocols at each layer are identified and packet encapsulation in TCP/IP is demonstrated.
This document provides an overview of computer networks and networking concepts. It discusses the OSI model and its seven layers, including the responsibilities of each layer. It also describes the TCP/IP protocol suite and how it maps to the OSI model. Physical network topologies like star, bus, ring and mesh are defined. The document examines addressing in TCP/IP networks, including physical, logical, and port addresses. Network devices, protocols, and the exchange of data across the OSI model layers are summarized as well.
Get custom writing services for OSI Model Assignment help & OSI Model Homework help. Our OSI Model Online tutors are available for instant help for OSI Model assignments & problems.OSI Model Homework help & OSI Model tutors offer 24*7 services . Send your OSI Model assignments at support@globalwebtutors.com or else upload it on the website. Instant Connect to us on live chat for OSI Model assignment help & OSI Model Homework help.
This document discusses the ISO-OSI 7-layer reference model and related IEEE standards for network communications. It provides an overview of the ISO and its 7-layer OSI model, describing each layer's function and how layers communicate with each other. It also discusses how the IEEE 802 group sets standards for the data link and physical layers, including specific standards for common network types like Ethernet, Token Ring, wireless, etc. The overall purpose is to explain the layered network communication model and standards that enable interoperability.
The document provides information about the OSI model and TCP/IP reference model. It describes the seven layers of the OSI model from the physical layer to the application layer and summarizes the responsibilities of each layer. It then compares the OSI model to the TCP/IP reference model, noting their similarities like layered architecture and application layers, as well as differences such as TCP/IP combining layers and being more simplified.
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.
Sargation university's open system interconnectionKingPinYT
The document discusses the OSI Reference Model and TCP/IP protocol suite. It provides details on the 7 layers of the OSI model from the physical layer to the application layer. It then explains the 4 layers of the TCP/IP model - network interface, internet, transport, and application layers. Key protocols at each layer like IP, TCP, UDP, FTP, SMTP, Telnet, and HTTP are also mentioned. The differences between OSI and TCP/IP models are summarized focusing on their layered architecture and approach to reliability.
The document discusses the OSI model and networking fundamentals. It defines the seven layers of the OSI model from the physical layer to the application layer. It also compares the OSI model to the TCP model. The physical layer defines cables and physical components. The data link layer provides error-free transmission using frames and MAC addresses. The network layer uses IP addresses for routing. The transport layer segments messages and ensures reliable delivery. The session, presentation and application layers establish communication sessions and enable user applications.
This document provides an overview and syllabus for a computer networking course. It will take a top-down approach, beginning with what services distributed applications require from networks and how networks provide those services. The course will cover topics including network edge, access, and core; delay, loss and throughput; protocol layers and models; network programming; and the application, transport, network, link and physical layers of the TCP/IP stack. The instructor is Dr. Nauman Mazhar and the course will include lectures, assignments, quizzes, and exams.
The document discusses network devices, communication protocols, and related topics. It describes the OSI reference model and TCP/IP model, detailing the layers and functions of each. It provides information on IP addressing, DNS, and gateway addressing. The OSI model has 7 layers including physical, data link, network, transport, session, presentation, and application layers. The TCP/IP model has 4 layers comprising network interface, internet, transport, and application layers.
This document discusses network architectures and protocols. It describes the OSI 7-layer model and the TCP/IP model. The key layers of each model are presented, including their functions and example protocols. Encapsulation is defined as the process of adding header and trailer data to messages at each layer. This allows protocols to communicate indirectly through lower level protocols in the protocol graph.
This document provides an overview of the syllabus for a Computer Networks course. It includes:
- An outline of the course units which cover data communication components, the OSI model, TCP/IP model, and each layer of the OSI model from layers 2 through 7.
- Evaluation criteria which includes continuous internal evaluation, semester end examination, and mandatory minimum marks.
- Suggested reading materials including textbooks and publications.
- An overview of the Computer Networks lab covering various experiments involving networking tools, protocols, programming, and simulation.
The document discusses network security models and the OSI reference model. It describes the seven layers of the OSI model from the physical layer to the application layer. It then discusses the TCP/IP reference model and its four layers from the link layer to the application layer. The document summarizes key protocols associated with each layer, including IP, TCP, UDP, and protocols that provide security at the transport and network layers like SSL/TLS and IPSec.
Here are the number of broadcast and collision domains for each case:
1. A single switch with 10 connected devices:
- Broadcast domain: 1
- Collision domain: 10 (each switch port is its own collision domain)
2. Two switches connected by a single trunk link with 10 devices on each switch:
- Broadcast domain: 2 (each switch is its own broadcast domain)
- Collision domain: 20 (each switch port is its own collision domain)
3. A router connecting two switches, each with 10 devices:
- Broadcast domain: 3 (each physical network segment is its own broadcast domain)
- Collision domain: 20 (each switch port is its own collision domain)
Here are the number of broadcast and collision domains for each case:
1. A single switch with 10 connected devices:
- Broadcast domain: 1
- Collision domain: 10 (each switch port is its own collision domain)
2. Two switches connected by a single trunk link with 10 devices on each switch:
- Broadcast domain: 2
- Collision domain: 20 (each switch port is its own collision domain)
3. A router connected to two switches, with 10 devices on each switch:
- Broadcast domain: 3
- Collision domain: 20 (each switch port is its own collision domain)
The document discusses operating systems and the OSI reference model. It describes how an operating system acts as an interface between the user and computer hardware, controlling programs and resources. It also outlines the seven layers of the OSI model, including what each layer is responsible for in network communication and the services provided between layers.
This document provides an overview of the OSI reference model, which is an internationally standardized architecture for how computer networks are structured. It consists of 7 layers, with each layer building on the services of the layer below. The bottom 4 layers relate to communication technologies, while the top 3 layers relate to applications and services for users. Each layer has a specific role, such as the physical layer defining hardware connections, the data link layer packaging bits into frames, and the application layer supporting software applications like file transfers. The model aims to promote interoperability between different computer systems.
The document provides an overview of network reference models and standards, specifically explaining the OSI reference model and IEEE 802 networking model. The OSI model is a seven-layer framework for networking that separates functions into the physical, data link, network, transport, session, presentation, and application layers. The IEEE 802 standards define networking interfaces and cabling to ensure compatibility between devices.
Open Systems Interconnection (OSI) is a set of internationally recognized, non-proprietary standards for networking and for operating system involved in networking functions.
This document provides an overview of the OSI reference model, which is an internationally standardized architecture for how network communication should work. It describes the seven layers of the OSI model from the physical layer up to the application layer. Each layer provides services to the layer above it and receives services from the layer below. The layers relate to either communication technologies (layers 1-4) or user applications (layers 5-7). The document also discusses how the OSI model differs from Internet protocols and covers concepts like connection types, reliability, and the relationship between services and protocols.
This document provides an overview of the OSI reference model, which is an internationally standardized architecture for how network communication should work. It describes the seven layers of the OSI model from the physical layer up to the application layer. Each layer provides services to the layer above it and receives services from the layer below. The layers relate to either communication technologies (layers 1-4) or user applications (layers 5-7). The document also discusses how the OSI model differs from Internet protocols and covers concepts like connection types, reliability, and the relationship between services and protocols.
This document provides an overview of the OSI reference model, which is an internationally standardized architecture for how network communication should work. It describes the seven layers of the OSI model from the physical layer up to the application layer. Each layer provides services to the layer above it and receives services from the layer below. The layers relate to either communication technologies (layers 1-4) or user applications (layers 5-7). The document also discusses how the OSI model differs from Internet protocols and covers concepts like connection types, reliability, and the relationship between services and protocols.
3. Chapter Objectives
• Discuss the most popular ISO-OSI 7-
layer communication reference model
• Explain the reference model and
standards relevant to network
communications
• Describe the different IEEE standards
that apply to different types of
networks
5. Models and Standards in
Communication
• Communication
– Established standards
– Standards are known as protocols
• Implementation
– A framework is helpful in the design of
hardware and software for communication
– ISO-OSI Model serves this purpose
– ISO-OSI supersedes the TCP/IP model
6. ISO and OSI Defined
• ISO
– International Standards Organization
• OSI
– Open Systems Interconnect
7. OSI Model Background
• Introduced in 1978 and revised in 1984
• Formulates the communication process
into structured layers
• There are seven layers in the model,
hence the name the 7-Layer model
• The model acts as a frame of reference
in the design of communications and
networking products
8. The Layered Approach to
Communication
7. Application
6. Presentation
5. Session
4. Transport
3. Network
2. Data Link
1. Physical
9. Division of Layers
Upper Layers
Middle Layer
Lower Layers
7. Application
6. Presentation
5. Session
4. Transport
3. Network
2. Data Link
1. Physical
10. The Function of a Layer
• Each layer deals with one aspect of
networking
– Layer 1 deals with the communication media
• Each layer communicates with the adjacent
layers
– In both directions
– Ex: Network layer communicates with:
• Transport layer
• Data Link layer
• Each layer formats the data packet
– Ex: Adds or deletes addresses
11. Role of Layers
7. Application
6. Presentation
1. Physical
Node A
Data In
Data Out
To/from
Node B
20. 6. Presentation Layer
• Purpose
– Formats data for exchange between points
of communication
•Ex: Between nodes in a network
• Example:
– Redirector software
•Formats for transmission to the server
21. Presentation Layer Function
• Protocol conversion
• Data translation
• Encryption
• Character set conversion
• Expansion of graphics command
23. 5. Session Layer
• Purpose
– Oversee a communication session
•Establish
•Maintain
•Terminate
• Example
24. Session Layer Function
• Performs name recognition and related
security
• Synchronization between sender and
receiver
• Assignment of time for transmission
– Start time
– End time etc.
25. 4. Transport Layer
• Purpose
– Repackage proper and efficient delivery of
packages
•Error free
•In sequence
•Without duplication
• Example
26. Transport Layer Function
• For sending data
– Repackage the message to fit into packets
• Split long messages
• Assemble small messages
• On receiving data
– Perform the reverse
– Send an acknowledgment to the sender
• Solve packet problems
– During transmission and reception
27. 3. Network Layer
• Purpose
– Addressing and routing the packets
• Example application at the router
– If the packet size is large, splits into small
packets
28. Network Layer Function
• Address messages
• Address translation from logical to
physical
– Ex: nganesa ----------> 102.13.345.25
• Routing of data
– Based on priority
– Best path at the time of transmission
• Congestion control
31. 2. Data Link Layer
• Purpose
– Manages the flow of data over the physical
media
• Responsible for error-free transmission
over the physical media
• Assures error-free data submission to
the Network Layer
32. Data Link Layer Function
• Point of origin
– Packages data for transmission over physical line
• Receiving end
– Packages data for submission to the network layer
• Deals with network transmission protocols
– IEEE 802. protocols
33. Data Link Layer Subdivision
• Improvement to ISO Model
• Logical Link Control (LLC) sub-layer
– Manages service access points (logical link)
– Error and flow control
•Media Access Control (MAC) sub-layer
– Applies directly to network card
communication
– Access control
35. Media Access Control
Application
• Network Interface Card driver
NETWORK
SOFTWARE
NETWORK
CARD
NIC Driver
facilitates data
transfer
36. 1. Physical Layer
• Purpose
– Deals with the transmission of 0s and 1s
over the physical media
•Translation of bits into signals
• Example
– Pulse duration determination
– Transmission synchronization
– etc.
37. Physical Layer Function
• Encode bits into signals
– Carry data from the h higher layers
• Define the interface to the card
– Electrical
– Mechanical
– Functional
– Example: Pin count on the connector
38. Lower Layers Application Areas
• Special significance to network card design
• Applies to general LAN hardware design
– Exceptions
• Routers etc.
• 802. standards
– Centered around the lower layers
– Applies to networks
41. Layer Operations
• At each layer, additional information is
added to the data packet
• An example would be information
related to the IP protocol that is added
at Layer 3
42. Formatting of Data Through the
Layers
Application Header Presentation Header Session Header
Network Header Transport Header
Data Link Header and Trailer Physical Frame Preamble
43. Packet : General Format
Header Trailer
Data
A general concept of packets serves as a prerequisite to
the understanding of the ISO-OSI model.
44. Some Header Information Added at
Various Layers
• Packet arrival information
• Receiver’s address
• Sender’s address
• Synchronization character
45. Data
• Actual data
• May contain error correction code
– Performed on individual characters of the data
– Example: Parity
• Size may vary
– Depending on the protocol
– Example
• 802.3 specifies range of data packet length
46. Some Trailer Information Added at
Various Layers
• Error correction code
– Character oriented
– VRC (Parity Checking)
• Packet oriented error correction codes
– LRC
– CRC
47. A Note on CRC
• Used widely
• Sophisticated
– Polynomial of deferent degrees are used
for error correction
– Example: Degrees 16, 32 etc.
• CRC-32 is a more stringent error
checking procedure than CRC-16
48. Some of the Major Components of
the Data Packet
Receiver’s
Address
Sender’s
Address
Control
Data
Data
Error
Correction
Protocol
Start/synch
Information
49. Standardizing Packet Formatting
• Packets must conform to a standard in order
for the nodes in a network to be able to
communicate with one another
• The International Standards Organization
(ISO) has provided a reference model
• Standards are established for operations at
each layer of the ISO/OSI model in the form
of protocols
52. IEEE Background
• Institution of Electrical and Electronic
Engineers (IEEE)
– A professional non-profit organization
• Project group 802
– Responsible for setting standards relating
to the physical link of the network
53. IEEE 802 Focus
• OSI Reference
– Data Link layer
– Physical layer
• Areas
– Network cards and cables
– Network electronic/optical/ wireless
communication standard as they apply to the
lower two layers mentioned above
– WAN connectivity
54. Upper Layer Focus
• IETF
•W3C
• ISO/IEC
• The above agencies focus on setting
standards on higher level protocol
– TCP, IP etc.
55. IEEE 802 Committees And
Responsibilities
• 802.1
– Internetworking
• 802.2
– Logical Link Control (LLC)
• 802.3
– CSMA/CD
• 802.4
– Token Bus LAN
56. IEEE 802 Committees and
Responsibilities (Cont.)
• 802.5
– Token Ring LAN
• 802.6
– Metropolitan Area Network
• 802.7
– Broadband Technical Advisory Group
• 802.8
– Fiber-Optic Technical Advisory Group