1-Describe the 7-layer OSI network reference model. List all 7 components. The 7-layer OSI network reference model delineates a hierarchy of abstract building blocks that provide basic protocols and services in a logically separated manner for the standardization of networks (Serpanos & Wolf, 2011; Cowley, 2012; Egyedi, 1997). The OSI network reference model was developed by the International Organization for Standardization (ISO) to facilitate communication between networks by keeping certain standards open rather than proprietary (Serpanos & Wolf, 2011). Each layer is stacked with the physical layer as the lowest and the application layer as the highest and one can think of each layer as containing stacks of protocols that make network communications function (Serpanos & Wolf, 2011). A protocol is a set of rules written in a common language that allows computers to communicate with each other. Each communication network is a node and the corresponding layer on each node communicates with each other. The seven layers, from lowest to highest, are physical, data link control, network, transport, session, presentation, and application. Data travels along the layers on the sending node from the application layer down through the layers until it reaches the physical layer. At the physical layer the data is transmitted over the physical medium to the physical layer at the receiving node. At this point, the data travels up the layers until it reaches the application layer in a format the end user can utilize (Cowley, 2012). Layer 2, the data-link control layer, is actually divided into two sublayers, the media access control (MAC) and the logistical link control (LLC). This modification occurred to the reference model due to the I... ... middle of paper ... ...ferent platforms (Melendez & Peterson, 1999). The highest layer in the OSI model is the application layer. While all other layers provide a general service to the other layers, the application does not provide any general services to the other layers (Melendez & Peterson, 1999). The application layer handles items not addressed in any of the lower levels and also handles details specific to distributed applications. Some examples of distributed applications are the hypertext transfer protocol (HTTP), the domain name system (DNS), and the session initiation protocol (SIP) (Serpanos & Wolf. 2011). The OSI model names the seventh layer as the application layer but does not specifically include any of the above-mentioned examples since the OSI model is abstract. As end users, we utilize the application layer every time we enter an HTTP URL in our internet server.
2. Battle Management, Command, Control, and Communications (BM/C3): The BM/C3 component is divided into two main parts. First, the Command and Control (BM/C2) system controls the overall NMD system. Information from sensors is forwarded to the BM/C2, which processes the data and determines the targets for the GBI to intercept. Second, the In-Flight Interceptor Communications System (IFICS) is a network of ground systems that relay communications to the GBI while in flight to guide it to the incoming warhead.
Multiplexing will gather the data from the source host and give that data some header information. This data will be created into segments by demultiplexing and then be sent to the 3rd layer (Network layer). So to summarize multiplexing will gather data and give it header information and demultiplexing will create segments and sent them to the network layer. Now with flow control that will relate with multiplexing, mainly because it can take multiple data streams and combine them into one shared stream, making that a form of data flow control. Now as far as error checking that will relate to the frames of the data. The logical link control will use a frame check sequence (FCS) to check the frame to see if there is any problems with it. If it detects an error during the frame check sequence then the frame will be discarded and the data will be passed on to the network layer. With this all being said this will mainly be used in the OSI model since the logical link control is the sub-layer for the data link layer. (The other sub layer being MAC) Without the logical link control or 802.2 then the data link layer wouldn’t function
An example of a highly important protocol which will be utilized at application level, is HTTP or hypertext transfer protocol. HTTP is the protocol used within web browsers and the entire internet to send and receive specific web page data. HTTP is a controlling protocol, as it determines how documents should be sent, and what the browser should do in response to commands. When accessing a web page, a HTTP command is sent to the pages web server, so that the server may send that specific page’s data to the user. PCO’s Learning Centre will be using the hypertext transfer protocol on a regular basis. In order for students to access web pages, the HTTP must exist to ensure speedy and accurate navigation, especially in a learning
OSI – Open Systems Interconnection - is reference model for how applications can communicate over a network. A reference model is a conceptual framework for understanding relationships.
Secondly, the seven layers proposed by OSI are completely out of touch with reality. The defacto networking standard is TCP/IP. TCP/IP is the grandaddy of XNS, IPX/SPX, Banyan, AppleTalk, and a host of other protocols and pre-dates that seven layer thing because it was funded by the largest organization in the world devoted to maintaining Eurocentric socioeconomic domination; the US Military. And for some reason, that makes it better. Yeah.
Switches operate within the OSI’s layer 2. This is known as the data link layer. The data link layer is responsible for the transfer of data frames from node to node across OSI’s layer one, the physical layer. This allows layers in the upper levels to have transmissions with error checking processes. The data link layer has several responsibilities of its function in the OSI model. The first is link establishment and termination which is where, between two separate nodes, it establishes and terminates the links that connect the two. Layer two also provides traffic control for the frames in transmission.
Analysis of the Environment of the Mobile Network System Executive Summary 3 Glossary of Abbreviations 4 Introduction 5 Recent History
An Open Shortest Path First (OSPF) protocol is the most used interior gateway protocol and computation intensive protocol where energy consumption in Internet Protocol (IP) networks is the main concern. The energy in an IP network can be saved by allowing a subset of IP router interfaces on sleep mode setting during the low traffic hours through the model of “move” by dint of an Energy Aware Routing (EAR) strategy, which is completely compatible with OSPF and is based on the “Shortest Path Tree (SPT) exportation” techinque or “Dijkstra's Algorithm”. In case of heavy traffic hours, the EAR strategy is not usable and may cause denial of service. The strategy implemented can help a network operator to control the network performance and allow a smoothed QoS degradation. This performance evaluation study permits to save about 30% of network links with a insignificant rise of link loads and network path lengths.
The data-link layer provides error-free transfer of data frames from one computer to another over the physical layer. The layers above this layer can assume virtually error-free transmission over the network. The data-link layer provides the following functions.
In 1994, ZAMNET Communication Systems was established as an Internet Service Provider (ISP) in Zambia. It was the first organization that was put in place to provide the internet services in the region. ZAMNET Communication Systems was strategically located at the University of Zambia so that it can be used in providing research for the highest institution of learning and in turn it could have also benefited from the Research and Development (R&D) from the institution being the highest learning institution in Zambia. Other higher learning institutions in the region could have also benefitted from the synergistic effects of partnering together with the University o...
Next, the writer goes over the second type of network architecture - the TCP/IP reference model, the granddaddy of the wide area computer network. This architecture allows the connection of multiple networks seamlessly. The architecture is flexible and capable of running even if some of the subnet hardware is destroyed or non-functional as long as the source and destination machines are functioning. In a similar fashion to the OSI model, the TCP/IP model has layers as well. In this case, we have four layers: the link
The OBJECT-TYPE layer is use to specify the data type, status, and the semantics of managed objects. It has basic of five mandatory characteristics namely, OBJECT-NAME, SYNTAX, MAX ACCESS, STATUS, and DESCRIPTION, optionally with OPTIONAL-CHARACTERISTICS. The OBJECT-NAME is obviously. The SYNTAX clause specifies the basic data type of the object. The MAX-ACCESS clause specifies the managed object either can be read-create, read-write, read-only, accessible for notify only, or not accessible. The STATUS clause specifies the object is current, obsolete or deprecated. The DESCRIPTION clause contains a textual definition of the object. [RFC2578][RFC2013]
ErrealMedia (2010) Network standards OSI Reference Model; History of OSI Model; OSI Layers in Action http://www.erealmedia.com/cms125/
Explain how the two important transport protocols deliver messages on behalf of the application and discuss the differences between them
There are several advantages to the layered approach provided by the OSI model. With the design separated into smaller logical pieces, network design problems can be easier to solve through divide and conquer techniques. Vendors who follow the model will produce equipment that is much more likely to be compatible with equipment from other vendors. The OSI model also provides for more extensible network designs. New protocols and other network services are more easier added to a layered architect.