Seven Processes of the Open Systems Interconnection - Report Example

?OSI LAYERS OSI Layers Affiliation Table of Contents Introduction 3 Seven Layers in OSI Model 4 APPLICATION LAYER 5 The first and outer layer of OSI model is recognized as application layer. In fact, it is the network layer that is responsible for dealing with collaborations and communication programs on the communication network, comprising file transfer protocol (FTP), HTTP (hypertext transfer protocol), and email. Additionally, these systems allow internet browsers and email systems to share data all through a network. In this scenario, the application layer works closely with software applications (like that Outlook Express or Netscape) that apply a communication part. However, other similar system programs are not included in the scope of OSI model; however they perceive an end user's typing into a Layer 1 demand (Holmes, 2011; RingofSaturn, 2011). In other words, the application layer works as an interface between users and network. Thus, it allows the users to access network operational services. In addition, this layer holds a multiplicity of required processes: (Microsoft, 2011)  5 PRESENTATION LAYER 6 The presentation layer offers a range of encoding and encryption processes that are applied to the data received from application layer. The purpose of these processes is to make sure that information received from the application layer of one system will be understandable to the application layer of another system. In addition, it works as a translator of the network since it translates the data to be accessible to the system’s application layer. In addition, the presentation layer is responsible for carrying out following tasks: (RingofSaturn, 2011; Microsoft, 2011; Nash, 2000) 6 SESSION LAYER 7 Session layer is responsible for systematizing and structuring communication among application procedures, facilitating two-way concurrent or two-way exchange process, organizing major and minor synchronization points and structuring data interactions. In addition, the session layer establishes session among processes depending on different stations. It is responsible for carrying out following takes: (Fairhurst, 2001)  7 TRANSPORT LAYER 8 The transport layer makes sure that messages are transmitted error-free, in series, and with no duplications or losses. In this scenario, the complexity and size of a network transport protocol completely depends upon the kind of service which is presented to it by the network layer. In addition, for a trustworthy network layer with virtual circuit potential, a negligible transport layer is necessary. On the other hand, if the network layer is untrustworthy and/or simply facilitates datagram transitions method, the transport protocol should encompass widespread error discovery and recovery methods. Moreover, the transport layer is responsible for carrying out following tasks: 8 NETWORK LAYER 9 Network layer offers freedom from data transfer technology and routing concerns, masks peculiarities of data transport medium from higher layers and offers switching and routing processes to create, uphold, and end network layer links and transfer data among various users. In this scenario, the network layer is mainly responsible for controlling the processes of the subnet, and making a decision that which physical path the data should be based upon, main concerns of service, and other aspects. In addition, network layer of OSI model carries out following tasks: (Fairhurst, 2001; Fairhurst, The Internetwork Protocol (IP), 2008; Microsoft, 2011) 9 DATA LINK LAYER 10 The data link layer is the place where logical data and information (for example network IP addresses) are actually interpreted into the electrical pulses that move over the physical layer. In addition, ATM, Frame Relay and DSL follow Data Link layer mechanisms. Additionally, the OSI model data link layer offers error-free communication of data frames from one node to another network node over the physical layer, permitting layers above it to suppose virtually error-free data and network transmission above a communication link. Moreover, data link layer carries out following tasks:  (RingofSaturn, 2011; Microsoft, 2011; Nash, 2000) 10 PHYSICAL LAYER 11 The physical layer outlines the mechanical, electrical, functional and procedural conditions for turning-on, upholding and deactivating the physical link among communicating network systems. In this scenario, physical layer describe conditions like that timing of voltage transformations, voltage levels, physical data rates, utmost transmission spaces and the physical connectors to be utilized. In addition, physical layer carries out following tasks: (RingofSaturn, 2011; Microsoft, 2011; Nash, 2000) 11 Conclusion 11 References 12 Executive Summary This report presents a detailed overview of open system interconnection (OSI) model. Open systems interconnection is a model which demonstrates how messages should be sent over a telecommunication and data transmission network. However, it does not comprise comprehensive interfaces. Additionally, OSI model is divided into seven layers and each layer outlines some rules and regulations for the communication. The open systems interconnection comprises seven processes, recognized as functional layers that should be carried out when messages are transmitted over the network. Finally, OSI is a model which can be followed by network designers while designing and maintaining a network. This report will discuss OSI model and its associated layers in detail. Introduction This report presents an overview of OSI model. This paper will discuss how different layers of an OSI model work together to smooth the process of communication. The OSI (open system interconnection) Model demonstrates how information and data communications should take place. Additionally, it divides communication process and working of network into seven different groups known as OSI network layers. In addition, the communication and working protocol standards that ISO (international standard organization) and other standards are incorporated into these network layers. In this scenario, some of the well known standards include IEEE (Institute of Electrical and Electronic Engineers), ANSI (or American National Standards Institute), and ITU (International Telecommunications Union) previously recognized as CCITT (Comite Consultatif Internationale de Telegraphique et Telephone). However, the OSI Model is responsible for deciding what protocols and standards should be implemented at a specific network layer (Emma, 2011; Rose India, 2008; Tech-Faq, 2011; Nash, 2000). Moreover, the OSI reference model was developed by IOS (International Organization for Standardization). In fact, the International Organization for Standardization is a group which is based on more than 160 nations that work in cooperation in order to produce operational standards to promote collaboration and communication among different nations. In addition, the suggestions for open system interconnection are programmed in section X.200 of the ITU-TS (International Telecommunications Union - Telecommunications Standards) (Emma, 2011; Rose India, 2008; Tech-Faq, 2011). Seven Layers in OSI Model International Standard Organization's Open System Interconnection (ISO/OSI) network and communication model is the standard representation for networking protocols and distributed applications. It is divided into 7 network communication layers, which are outline below: (Petri, 2009)  Layer Name 1 Application 2 Presentation 3 Session 4 Transport 5 Network 6 Data Link 7 Physical The below given image demonstrates the overall working and data status of the network layers in respective point of communication: Figure 1OSI Model Description, Image Source: http://www.tech-faq.com/osi-model.html APPLICATION LAYER The first and outer layer of OSI model is recognized as application layer. In fact, it is the network layer that is responsible for dealing with collaborations and communication programs on the communication network, comprising file transfer protocol (FTP), HTTP (hypertext transfer protocol), and email. Additionally, these systems allow internet browsers and email systems to share data all through a network. In this scenario, the application layer works closely with software applications (like that Outlook Express or Netscape) that apply a communication part. However, other similar system programs are not included in the scope of OSI model; however they perceive an end user's typing into a Layer 1 demand (Holmes, 2011; RingofSaturn, 2011). In other words, the application layer works as an interface between users and network. Thus, it allows the users to access network operational services. In addition, this layer holds a multiplicity of required processes: (Microsoft, 2011)  Network virtual terminals Network remote file access Resource sharing as well as device redirection Network administration Electronic messaging (such as e- mail) Network directory services Access to network remote printer Network Inter-process collaboration and communication PRESENTATION LAYER The presentation layer offers a range of encoding and encryption processes that are applied to the data received from application layer. The purpose of these processes is to make sure that information received from the application layer of one system will be understandable to the application layer of another system. In addition, it works as a translator of the network since it translates the data to be accessible to the system’s application layer. In addition, the presentation layer is responsible for carrying out following tasks: (RingofSaturn, 2011; Microsoft, 2011; Nash, 2000) Data alteration: data types like that CR-CR/LF, bit order, integer-floating point, etc. Character code conversion: for instance, EBCDIC to ASCII. Data encryption: hide and encrypt data intended for safety reasons. For instance, password encryption. Data compression: minimizing the amount of bits that require to be transmitted on the communication network. SESSION LAYER Session layer is responsible for systematizing and structuring communication among application procedures, facilitating two-way concurrent or two-way exchange process, organizing major and minor synchronization points and structuring data interactions. In addition, the session layer establishes session among processes depending on different stations. It is responsible for carrying out following takes: (Fairhurst, 2001)  Establishing, upholding and killing: permits two applications or processes on different technologies to launch, utilize and finish a connection, known as the session. Session support: carries out the processes that permit these procedures to communicate over the communication network, carrying out security, logging, name recognition, etc. TRANSPORT LAYER The transport layer makes sure that messages are transmitted error-free, in series, and with no duplications or losses. In this scenario, the complexity and size of a network transport protocol completely depends upon the kind of service which is presented to it by the network layer. In addition, for a trustworthy network layer with virtual circuit potential, a negligible transport layer is necessary. On the other hand, if the network layer is untrustworthy and/or simply facilitates datagram transitions method, the transport protocol should encompass widespread error discovery and recovery methods. Moreover, the transport layer is responsible for carrying out following tasks: Session multiplexing: multiplexes a number of message streams, or sessions onto one rational link as well as maintains track of those messages in the right place to which sessions. Message acceptance: offers dependable and end-to-end message transmission with acceptances. Message segmentation: recognizing a message from the (session) layer on top of it, cracks the message into lesser parts (if not previously small adequate), as well as transmits the smaller parts down to the OSI network layer in order that the transport layer at the target position reassembles the message. Message traffic control: Verifies the transmitting position to "back-off" when no data or communication buffers exist. NETWORK LAYER Network layer offers freedom from data transfer technology and routing concerns, masks peculiarities of data transport medium from higher layers and offers switching and routing processes to create, uphold, and end network layer links and transfer data among various users. In this scenario, the network layer is mainly responsible for controlling the processes of the subnet, and making a decision that which physical path the data should be based upon, main concerns of service, and other aspects. In addition, network layer of OSI model carries out following tasks: (Fairhurst, 2001; Fairhurst, The Internetwork Protocol (IP), 2008; Microsoft, 2011) Routing: routes data and communication frames between networks and layers. Frame fragmentation: if it determines that the size of a downstream router's utmost transmission unit (MTU) is much smaller than data transmission frame size, a router is able to fragment a network data frame for transmission as well as re-assemble at the destination location. Subnet practice accounting: plays the role of bookkeeper in order to manage and handle functions of network frames forwarded by subnet transitional systems, to create billing information. Logical-physical mapping: interprets logical addresses, or names into network and communication physical addresses. DATA LINK LAYER The data link layer is the place where logical data and information (for example network IP addresses) are actually interpreted into the electrical pulses that move over the physical layer. In addition, ATM, Frame Relay and DSL follow Data Link layer mechanisms. Additionally, the OSI model data link layer offers error-free communication of data frames from one node to another network node over the physical layer, permitting layers above it to suppose virtually error-free data and network transmission above a communication link. Moreover, data link layer carries out following tasks:  (RingofSaturn, 2011; Microsoft, 2011; Nash, 2000) Frame traffic management and control: informs the sender’s network node to "retreat" when no data frame memory buffers are obtainable. Establishing and Terminating Link: setups as well as ends the logical link among 2 network nodes. Frame recognition: offers/expects network frame acknowledgments. Checks as well as recovers from errors that happen in the network physical layer by retransmitting non-acknowledged network data frames as well as managing replacement frame receipt. Frame sequencing: receives or transmits network frames in order. Frame defining: makes as well as distinguishes network data frame limitations. Media access administration: decides when the node "has the authority" to make use of the network physical means. Frame error examination: confirms received network data frames for reliability. PHYSICAL LAYER The physical layer outlines the mechanical, electrical, functional and procedural conditions for turning-on, upholding and deactivating the physical link among communicating network systems. In this scenario, physical layer describe conditions like that timing of voltage transformations, voltage levels, physical data rates, utmost transmission spaces and the physical connectors to be utilized. In addition, physical layer carries out following tasks: (RingofSaturn, 2011; Microsoft, 2011; Nash, 2000) Data encoding: changes the straightforward digital signal structure (1s and 0s) utilized by the PC to accommodate the uniqueness of the physical medium. In this scenario, it decides: What signal condition refers to a binary 1 How the target station distinguishes when a "bit-time" starts How the receipt station sets the limits of a frame Transmission method: At this stage, it decides whether the programmed bits will be sent through baseband (digital) or broadband (analog) network signaling. Physical medium transmission: broadcasts network data bits as electrical or optical signals whatever is suitable for the physical medium. Conclusion This report has presented a detailed overview of OSI model and its layers. OSI stands for Open systems interconnection. It is a network model which demonstrates how communication is done over a telecommunication and data transmission network. In order to smooth the process of communication, OSI model divides its tasks into seven layers. In other words, the open systems interconnection comprises seven processes, recognized as functional layers. Each layer of the OSI model performs some specific tasks. This report has discussed about all the layers and their associated tasks. OSI model is followed by network designers while designing and maintaining a network. References Emma, G. (2011). What Is Open Systems Interconnection? Retrieved November 15, 2011, from WiseGeek.com: http://www.wisegeek.com/what-is-open-systems-interconnection.htm Fairhurst, G. (2008, January 11). The Internetwork Protocol (IP). Retrieved November 17, 2011, from http://www.erg.abdn.ac.uk/~gorry/eg3567/inet-pages/ip.html Fairhurst, G. (2001, January 10). The OSI Reference Model. Retrieved November 15, 2011, from http://www.erg.abdn.ac.uk/~gorry/eg3567/intro-pages/osi.html Holmes, T. (2011). What Is an Application Layer? Retrieved November 18, 2011, from WiseGeek.com: http://www.wisegeek.com/what-is-an-application-layer.htm Microsoft. (2011). The OSI Model's Seven Layers Defined and Functions Explained. Retrieved November 19, 2011, from http://support.microsoft.com/kb/103884 Nash, J. (2000). Networking Essentials, MCSE Study Guide. California: IDG Books Worldwide, Inc. Petri, D. (2009, January 08). OSI Model Concepts. Retrieved November 17, 2011, from http://www.petri.co.il/osi_concepts.htm RingofSaturn. (2011, July 01). Seven Layer Model. Retrieved November 19, 2011, from http://networking.ringofsaturn.com/Protocols/sevenlayer.php Rose India. (2008, February 15). What is OSI Model? Retrieved November 14, 2011, from http://www.roseindia.net/technology/networking/osi.shtml Tech-Faq. (2011). The OSI Model – What It Is; Why It Matters; Why It Doesn’t Matter. Retrieved November 16, 2011, from http://www.tech-faq.com/osi-model.html Read More