OSI Model Ument 16.10.2015


OSI MODEL Communication Architecture Strategy for connecting host computers and other communicating equipmen Defines necessary elements for data communication between devices. Acommunication architecture, therefore, defines astandard for the communicating hosts. Aprogrammer formats data in amanner defined by the communication architecture and passes it on to the communication software. Separating communication functions adds flexibility, for example, we do not need to modify the entire host software to include more communication devices. Layer Architecture Layer architecture simplifies the network design. It is easy to debug network applications in alayered architecture network. The network management is easier due to the layered architecture. Network layers follow aset of rules, called protocol. The protocol defines the format of the data being exchanged, and the control and timing for the handshake between layers. Open Systems Interconnection (OSI) Model International standard organization (ISO) established acommiee in 1977 to develop an architecture for computer communication. Open Systems Interconnection (OSI) reference model is the result of this effor In 1984, the Open Systems Interconnection (OSI) reference model was approved as an international standard for communications architecture. Term "open" denotes the ability to connect any two systems which conform to the reference model and associated standards. OSI Reference Model The OSI model is now considered the primary Architectural model for inter-computer communications. The OSI model describes how information or data makes its way from application programmes (such as spreadsheets) through anetwork medium (such as wire) to another application programme located on another network. The OSI reference model divides the problem of moving information between computers over anetwork medium into SEVEN smaller and more manageable problems . This separation into smaller more manageable functions is known as layerin OSI Reference Model: 7 Layers OSI: ALayered Network Model The process of breaking up the functions or tasks of networking into layers reduces complexity. Each layer provides aservice to the layer above it in the protocol specification. Each layer communicates with the same layer's software or hardware on other computers. The lower 4 layers ranspor network, data link and physical ""Layers 4, 3, 2, and 1) are concerned with the flow of data from end to end through the network. The upper four layers of the OSI model (application, presentation and session""Layers 7, 6 and 5) are orientated more toward services to the applications. Data is Encapsulated with the necessary protocol information as it moves down the layers before network transi Physical Layer Provides physical interface for transmission of information. Defines rules by which bits are passed from one system to another on aphysical communication medium. Covers all - mechanical, electrical, functional and procedural - aspects for physical communication. Such characteristics as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, physical connectors, and other similar aributes are defined by physical layer specifications. Data Link Layer Data link layer aempts to provide reliable communication over the physical layer interface. Breaks the ouoing data into frames and reassemble the received frames. Create and detect frame boundaries. Handle errors by implementing an acknowledgement and retransmission scheme. Implement flow control. Supports points-to-point as well as broadcast communication. Supports simplex, half-duplex or full-duplex communication. Network Layer Implements routing of frames (packets) through the network. Defines the most optimum path the packet should take from the source to the destination Defines logical addressing so that any endpoint can be identified. Handles congestion in the network. Facilitates interconnection between heterogeneous networks (Internetworkin The network layer also defines how to fragment apacket into smaller packets to accommodate different media. Transport Layer Purpose of this layer is to provide areliable mechanism for the exchange of data between two processes in different computers. Ensures that the data units are delivered error free. Ensures that data units are delivered in sequence. Ensures that there is no loss or duplication of data units. Provides connectionless or connection oriented service. Provides for the connection managemen Multiplex multiple connection over asingle channel. Session Layer Session layer provides mechanism for controlling the dialogue between the two end systems. It defines how to star control and end conversations (called sessions) between applications. This layer requests for alogical connection to be established on an end-user's reques Any necessary log-on or password validation is also handled by this layer. Session layer is also responsible for terminating the connection. This layer provides services like dialogue discipline which can be full duplex or half duplex. Session layer can also provide check-pointing mechanism such that if afailure of some sort occurs between checkpoints, all data can be retransmied from the last checkpoin Presentation Layer Presentation layer defines the format in which the data is to be exchanged between the two communicating entities. Also handles data compression and data encryption (cryptography Application Layer Application layer interacts with application programs and is the highest level of OSI model. Application layer contains management functions to support distributed applications. Examples of application layer are applications such as file transfer, electronic mail, remote login etc. OSI in Action Amessage begins at the top application layer and moves down the OSI layers to the boom physical layer. As the message descends, each successive OSI model layer adds aheader to i Aheader is layer-specific information that basically explains what functions the layer carried ou Conversely, at the receiving end, headers are striped from the message as it travels up the corresponding layers. TCP/IP MODEL OSI & TCP/IP Models TCP/IP Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model OSI Model TCP/IP Model TCP/IP Model TCP/IP Model Application Layer Application programs using the network Transport Layer (TCP/UDP) Management of end-to-end message transmission, error detection and error correction Network Layer (IP) Handling of datagrams : routing and congestion Data Link Layer Management of cost effective and reliable data delivery, access to physical networks Physical Layer Physical Media OSI MODEL Communication Architecture Strategy for connecting host computers and other communicating equipmen Defines necessary elements for data communication between devices. Acommunication architecture, therefore, defines astandard for the communicating hosts. Aprogrammer formats data in amanner defined by the communication architecture and passes it on to the communication software. Separating communication functions adds flexibility, for example, we do not need to modify the entire host software to include more communication devices. Layer Architecture Layer architecture simplifies the network design. It is easy to debug network applications in alayered architecture network. The network management is easier due to the layered architecture. Network layers follow aset of rules, called protocol. The protocol defines the format of the data being exchanged, and the control and timing for the handshake between layers. Open Systems Interconnection (OSI) Model International standard organization (ISO) established acommiee in 1977 to develop an architecture for computer communication. Open Systems Interconnection (OSI) reference model is the result of this effor In 1984, the Open Systems Interconnection (OSI) reference model was approved as an international standard for communications architecture. Term "open" denotes the ability to connect any two systems which conform to the reference model and associated standards. OSI Reference Model The OSI model is now considered the primary Architectural model for inter-computer communications. The OSI model describes how information or data makes its way from application programmes (such as spreadsheets) through anetwork medium (such as wire) to another application programme located on another network. The OSI reference model divides the problem of moving information between computers over anetwork medium into SEVEN smaller and more manageable problems . This separation into smaller more manageable functions is known as layerin OSI Reference Model: 7 Layers OSI: ALayered Network Model The process of breaking up the functions or tasks of networking into layers reduces complexity. Each layer provides aservice to the layer above it in the protocol specification. Each layer communicates with the same layer's software or hardware on other computers. The lower 4 layers ranspor network, data link and physical ""Layers 4, 3, 2, and 1) are concerned with the flow of data from end to end through the network. The upper four layers of the OSI model (application, presentation and session""Layers 7, 6 and 5) are orientated more toward services to the applications. Data is Encapsulated with the necessary protocol information as it moves down the layers before network transi Physical Layer Provides physical interface for transmission of information. Defines rules by which bits are passed from one system to another on aphysical communication medium. Covers all - mechanical, electrical, functional and procedural - aspects for physical communication. Such characteristics as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, physical connectors, and other similar aributes are defined by physical layer specifications. Data Link Layer Data link layer aempts to provide reliable communication over the physical layer interface. Breaks the ouoing data into frames and reassemble the received frames. Create and detect frame boundaries. Handle errors by implementing an acknowledgement and retransmission scheme. Implement flow control. Supports points-to-point as well as broadcast communication. Supports simplex, half-duplex or full-duplex communication. Network Layer Implements routing of frames (packets) through the network. Defines the most optimum path the packet should take from the source to the destination Defines logical addressing so that any endpoint can be identified. Handles congestion in the network. Facilitates interconnection between heterogeneous networks (Internetworkin The network layer also defines how to fragment apacket into smaller packets to accommodate different media. Transport Layer Purpose of this layer is to provide areliable mechanism for the exchange of data between two processes in different computers. Ensures that the data units are delivered error free. Ensures that data units are delivered in sequence. Ensures that there is no loss or duplication of data units. Provides connectionless or connection oriented service. Provides for the connection managemen Multiplex multiple connection over asingle channel. Session Layer Session layer provides mechanism for controlling the dialogue between the two end systems. It defines how to star control and end conversations (called sessions) between applications. This layer requests for alogical connection to be established on an end-user's reques Any necessary log-on or password validation is also handled by this layer. Session layer is also responsible for terminating the connection. This layer provides services like dialogue discipline which can be full duplex or half duplex. Session layer can also provide check-pointing mechanism such that if afailure of some sort occurs between checkpoints, all data can be retransmied from the last checkpoin Presentation Layer Presentation layer defines the format in which the data is to be exchanged between the two communicating entities. Also handles data compression and data encryption (cryptography Application Layer Application layer interacts with application programs and is the highest level of OSI model. Application layer contains management functions to support distributed applications. Examples of application layer are applications such as file transfer, electronic mail, remote login etc. OSI in Action Amessage begins at the top application layer and moves down the OSI layers to the boom physical layer. As the message descends, each successive OSI model layer adds aheader to i Aheader is layer-specific information that basically explains what functions the layer carried ou Conversely, at the receiving end, headers are striped from the message as it travels up the corresponding layers. TCP/IP MODEL OSI & TCP/IP Models TCP/IP Model OSI MODEL Communication Architecture Strategy for connecting host computers and other communicating equipmen Defines necessary elements for data communication between devices. Acommunication architecture, therefore, defines astandard for the communicating hosts. Aprogrammer formats data in amanner defined by the communication architecture and passes it on to the communication software. Separating communication functions adds flexibility, for example, we do not need to modify the entire host software to include more communication devices. Layer Architecture Layer architecture simplifies the network design. It is easy to debug network applications in alayered architecture network. The network management is easier due to the layered architecture. Network layers follow aset of rules, called protocol. The protocol defines the format of the data being exchanged, and the control and timing for the handshake between layers. Open Systems Interconnection (OSI) Model International standard organization (ISO) established acommiee in 1977 to develop an architecture for computer communication. Open Systems Interconnection (OSI) reference model is the result of this effor In 1984, the Open Systems Interconnection (OSI) reference model was approved as an international standard for communications architecture. Term "open" denotes the ability to connect any two systems which conform to the reference model and associated standards. OSI Reference Model The OSI model is now considered the primary Architectural model for inter-computer communications. The OSI model describes how information or data makes its way from application programmes (such as spreadsheets) through anetwork medium (such as wire) to another application programme located on another network. The OSI reference model divides the problem of moving information between computers over anetwork medium into SEVEN smaller and more manageable problems . This separation into smaller more manageable functions is known as layerin OSI Reference Model: 7 Layers OSI: ALayered Network Model The process of breaking up the functions or tasks of networking into layers reduces complexity. Each layer provides aservice to the layer above it in the protocol specification. Each layer communicates with the same layer's software or hardware on other computers. The lower 4 layers ranspor network, data link and physical ""Layers 4, 3, 2, and 1) are concerned with the flow of data from end to end through the network. The upper four layers of the OSI model (application, presentation and session""Layers 7, 6 and 5) are orientated more toward services to the applications. Data is Encapsulated with the necessary protocol information as it moves down the layers before network transi Physical Layer Provides physical interface for transmission of information. Defines rules by which bits are passed from one system to another on aphysical communication medium. Covers all - mechanical, electrical, functional and procedural - aspects for physical communication. Such characteristics as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, physical connectors, and other similar aributes are defined by physical layer specifications. Data Link Layer Data link layer aempts to provide reliable communication over the physical layer interface. Breaks the ouoing data into frames and reassemble the received frames. Create and detect frame boundaries. Handle errors by implementing an acknowledgement and retransmission scheme. Implement flow control. Supports points-to-point as well as broadcast communication. Supports simplex, half-duplex or full-duplex communication. Network Layer Implements routing of frames (packets) through the network. Defines the most optimum path the packet should take from the source to the destination Defines logical addressing so that any endpoint can be identified. Handles congestion in the network. Facilitates interconnection between heterogeneous networks (Internetworkin The network layer also defines how to fragment apacket into smaller packets to accommodate different media. Transport Layer Purpose of this layer is to provide areliable mechanism for the exchange of data between two processes in different computers. Ensures that the data units are delivered error free. Ensures that data units are delivered in sequence. Ensures that there is no loss or duplication of data units. Provides connectionless or connection oriented service. Provides for the connection managemen Multiplex multiple connection over asingle channel. Session Layer Session layer provides mechanism for controlling the dialogue between the two end systems. It defines how to star control and end conversations (called sessions) between applications. This layer requests for alogical connection to be established on an end-user's reques Any necessary log-on or password validation is also handled by this layer. Session layer is also responsible for terminating the connection. This layer provides services like dialogue discipline which can be full duplex or half duplex. Session layer can also provide check-pointing mechanism such that if afailure of some sort occurs between checkpoints, all data can be retransmied from the last checkpoin Presentation Layer Presentation layer defines the format in which the data is to be exchanged between the two communicating entities. Also handles data compression and data encryption (cryptography Application Layer Application layer interacts with application programs and is the highest level of OSI model. Application layer contains management functions to support distributed applications. Examples of application layer are applications such as file transfer, electronic mail, remote login etc. OSI in Action Amessage begins at the top application layer and moves down the OSI layers to the boom physical layer. As the message descends, each successive OSI model layer adds aheader to i Aheader is layer-specific information that basically explains what functions the layer carried ou Conversely, at the receiving end, headers are striped from the message as it travels up the corresponding layers. TCP/IP MODEL OSI & TCP/IP Models TCP/IP Model OSI Model OSI MODEL Communication Architecture Strategy for connecting host computers and other communicating equipmen Defines necessary elements for data communication between devices. Acommunication architecture, therefore, defines astandard for the communicating hosts. Aprogrammer formats data in amanner defined by the communication architecture and passes it on to the communication software. Separating communication functions adds flexibility, for example, we do not need to modify the entire host software to include more communication devices. Layer Architecture Layer architecture simplifies the network design. It is easy to debug network applications in alayered architecture network. The network management is easier due to the layered architecture. Network layers follow aset of rules, called protocol. The protocol defines the format of the data being exchanged, and the control and timing for the handshake between layers. Open Systems Interconnection (OSI) Model International standard organization (ISO) established acommiee in 1977 to develop an architecture for computer communication. Open Systems Interconnection (OSI) reference model is the result of this effor In 1984, the Open Systems Interconnection (OSI) reference model was approved as an international standard for communications architecture. Term "open" denotes the ability to connect any two systems which conform to the reference model and associated standards. OSI Reference Model The OSI model is now considered the primary Architectural model for inter-computer communications. The OSI model describes how information or data makes its way from application programmes (such as spreadsheets) through anetwork medium (such as wire) to another application programme located on another network. The OSI reference model divides the problem of moving information between computers over anetwork medium into SEVEN smaller and more manageable problems . This separation into smaller more manageable functions is known as layerin OSI Reference Model: 7 Layers OSI: ALayered Network Model The process of breaking up the functions or tasks of networking into layers reduces complexity. Each layer provides aservice to the layer above it in the protocol specification. Each layer communicates with the same layer's software or hardware on other computers. The lower 4 layers ranspor network, data link and physical ""Layers 4, 3, 2, and 1) are concerned with the flow of data from end to end through the network. The upper four layers of the OSI model (application, presentation and session""Layers 7, 6 and 5) are orientated more toward services to the applications. Data is Encapsulated with the necessary protocol information as it moves down the layers before network transi Physical Layer Provides physical interface for transmission of information. Defines rules by which bits are passed from one system to another on aphysical communication medium. Covers all - mechanical, electrical, functional and procedural - aspects for physical communication. Such characteristics as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, physical connectors, and other similar aributes are defined by physical layer specifications. Data Link Layer Data link layer aempts to provide reliable communication over the physical layer interface. Breaks the ouoing data into frames and reassemble the received frames. Create and detect frame boundaries. Handle errors by implementing an acknowledgement and retransmission scheme. Implement flow control. Supports points-to-point as well as broadcast communication. Supports simplex, half-duplex or full-duplex communication. Network Layer Implements routing of frames (packets) through the network. Defines the most optimum path the packet should take from the source to the destination Defines logical addressing so that any endpoint can be identified. Handles congestion in the network. Facilitates interconnection between heterogeneous networks (Internetworkin The network layer also defines how to fragment apacket into smaller packets to accommodate different media. Transport Layer Purpose of this layer is to provide areliable mechanism for the exchange of data between two processes in different computers. Ensures that the data units are delivered error free. Ensures that data units are delivered in sequence. Ensures that there is no loss or duplication of data units. Provides connectionless or connection oriented service. Provides for the connection managemen Multiplex multiple connection over asingle channel. Session Layer Session layer provides mechanism for controlling the dialogue between the two end systems. It defines how to star control and end conversations (called sessions) between applications. This layer requests for alogical connection to be established on an end-user's reques Any necessary log-on or password validation is also handled by this layer. Session layer is also responsible for terminating the connection. This layer provides services like dialogue discipline which can be full duplex or half duplex. Session layer can also provide check-pointing mechanism such that if afailure of some sort occurs between checkpoints, all data can be retransmied from the last checkpoin Presentation Layer Presentation layer defines the format in which the data is to be exchanged between the two communicating entities. Also handles data compression and data encryption (cryptography Application Layer Application layer interacts with application programs and is the highest level of OSI model. Application layer contains management functions to support distributed applications. Examples of application layer are applications such as file transfer, electronic mail, remote login etc. OSI in Action Amessage begins at the top application layer and moves down the OSI layers to the boom physical layer. As the message descends, each successive OSI model layer adds aheader to i Aheader is layer-specific information that basically explains what functions the layer carried ou Conversely, at the receiving end, headers are striped from the message as it travels up the corresponding layers. TCP/IP MODEL OSI & TCP/IP Models TCP/IP Model OSI Model TCP/IP Model Application Layer Application programs using the network Transport Layer (TCP/UDP) Management of end-to-end message transmission, error detection and error correction Network Layer (IP) Handling of datagrams : routing and congestion Data Link Layer Management of cost effective and reliable data delivery, access to physical networks Physical Layer Physical Media Created with ppt Html