Microsoft Windows Java ISDN Information
Computer Software Management Products
|
|
|
Microsoft Windows Java ISDN Information |
| ||||
|
| ||||
|
SEO Elite marketing software - Norton Anti Virus - Create easy web video - Great software downloads - Music Movies Games Software | ||||
|
You are free to use content from this page in your blog or website, in return for a link back to this page from that blog or website.
OSI Layers Model
Introduction During the early years of our modern computer era, very few standards and protocols existed between various manufacturers. However, as time went on and computer technology continued to improve and become more widespread, it became apparent that standards would be necessary to ensure compatibility. This was especially true with regard to networks, and networking technology. Since the main purpose of a network is to share information, a standard that governs how this information is formatted, transmitted, received and verified would make it possible for information to be shared openly, even when dealing with dissimilar networks. This need for a standard means of implementing open communications led the ISO and ANSI to develop the seven-layer network communications model known as Open Systems Interconnect. By providing guidelines regarding the way network equipment should be manufactured and how network operating systems communicate on a network, the OSI model became the common link that allows data to be transmitted and exchanged reliably. Although it does not actually perform any functions or do any of the actual work, the OSI model defines the way things should be done by the software and hardware on a network so that communications can take place between two computers or nodes. In this way, the OSI model provides a universal set of rules that make it possible for various manufacturers and developers to create software and hardware that is compatible with each other. This makes for organized communications. As I thought about this, I related it to the freeways that connect the various states of the mainland U.S. Because all of these freeways were constructed with the same set of standards regarding the width of each lane, the proper side that a person should drive on, the speed at which they should travel, and so on, people can comfortably drive across the country in an organized and efficient manner and car manufacturers are able to design cars within these guidelines as well. On the other hand, if each state had devised its own set of rules, each differing from the other, not only would there be a lot more chaos on the roads, but also car manufacturers would have a hard time designing vehicles that would be compatible with each state's roads. To me, this illustrates the importance of the OSI model with respect to network communications. Not only is it the foundation for all network communications today, but also because it is such a fundamental part of these communications, it becomes very apparent to me that it is very important for a network technician to understand the OSI model in full detail. The OSI model is made up of the following layers: the physical, data link, network, transport, session, presentation and application. Together, these seven layers are collectively referred to as a stack. As a node receives data, each layer starting with the physical layer extracts the various portions of the packet and this process works its way up to the application layer. When data is sent, it begins at the application layer and travels down to the physical layer. The information is pushed to the next layer of the stack by means of commands called primitives. Each layer uses a peer protocol to encode the information, which ensures that the same layer on the receiving node will be able to understand the information. Physical Layer Beginning at the bottom, the first layer is the physical layer. It governs the actual voltages, type of electrical signals, mechanical connections and other items relating to the actual data transmission medium. This includes cabling types, distances and connectors, as well as protocols like CSMA/CD. Data Link Layer The next layer is the data link layer. This is the layer that actually constructs the frames, and it also performs error checking using CRC. It ensures that the frames are sent up to the next layer in the same order that they were received, providing an error free virtual path to the network layer. The data link layer consists of two sub layers; the logical link control (LLC) and the media access control (MAC), which provide reliable communications by ensuring the data link is not broken and also by examining packet address information. A bridge is an example of a device that works at this layer. A bridge learns, forwards and filters traffic by examining the layer 2 MAC address. This helps segment network traffic. More recently, bridges have been replaced by switches, which performs the same functions as a bridge, but can do so on each port. To find out more about switches, visit the Products link on the left. Network Layer Moving up to the next layer in the stack we come to the network layer. This layer actually routes packets of data, finding a path (both physical and logical) to the receiving or destination computer. It provides a unique address for each node through address resolution. One of the most common protocols for routing information at this layer is the Internet Protocol (IP). An example of hardware that can operate at this layer is a router. Although routers are often used to allow a LAN to access a WAN, layer 3 switches can also provide routing capabilities, but often at full wire-speed. Transport Layer The transport layer makes sure that the data arrives without errors, in the proper sequence and in a reliable condition. It uses flow control to make sure that information is sent at the proper speed for the receiving device to be able to handle it, and it repackages large data into smaller messages and then back again at the receiving node. An example protocol at this layer is the Transmission Control Protocol (TCP). Layer 4 switches can use the port information found in the TCP header to provide QoS (Quality of Service) and load balancing. To learn more about multi-layer switches, visit the Products link. Session Layer The session layer establishes the link between two nodes and ensures that the link is maintained and then disconnected. This is referred to as the session. It also makes sure the session is orderly, establishing which node transmits first, how long it can transmit, and what to do in case of an error. It also handles the security of the session. Presentation Layer The presentation layer deals with the actual formatting of the data. It handles compression, encryption, as well as translation to make sure differences in formatting can be read by the receiving node. For example, data might be converted from EBCDIC to ASCII formatting so that the receiving node can understand it. Application Layer This brings us to the seventh and final layer, the application layer. It allows applications access to network services, such as file and printer sharing, as well as file transfer and management services. This would be the layer that a programmer uses to allow his application to access a network service, such as linking into a database. Although this explains the flow of data and what processes are performed by each layer starting with the physical layer and working to the top, or application, layer, the process would be the same, only reversed, for data flowing from the application layer and down to the bottom, or the physical layer. Conclusion By adhering to this standard model of communications, modern networks, including the Internet, have come into existence. For anyone interested in implementing and supporting today's modern networks, an understanding of the OSI model and its various layers is crucial. Indeed, this standard of communications lays the foundation for all of todays modern network hardware and software. Kashif Raza http://www.networkingtutorials.net
Cat 18793 |
|
|
|
RELATED ARTICLES
C++ Tutorial 1, Introduction to C++ Introduction to C++ S is for Spying, Surveillance -- and for Software as Well Words we choose to describe things and phenomena often show our attitude towards what we say. They imperceptibly reflect our opinions and judgments, prejudices and preferences, moral convictions and beliefs. Whether we like it or not, good deal of words we use are biased, or should I say "slanted", --positively or negatively. Two people will call the same thing differently, depending on their points of view. The XP Firewall Isnt Enough Every computer that connects to the internet has an IP address. This is like a sort of phone number, and is issued either to an individual computer or to a "gateway" that connects a private network to the 'net. Artificial Intelligence And Intuition The intuitive algorithm. Popular Fleet Maintenance Programs Some companies that are in need of fleet management may choose to utilize the services of a fleet maintenance program. These programs can generally handle all of you fleet management needs. Tracking vehicles, keeping up with maintenance, handling fuel budgeting and logging work are among a few examples of what fleet maintenance programs can offer your company. Increase Office Efficiency With One Simple Tool When you need a phone number, you do a quick search on the Internet and in a few seconds, you've got the information you need. And you probably receive a lot of contact information right inside the emails you receive every day. Both methods are by far more convenient than using those white or yellow-colored telephone directories. Information Products: A Business Owners Best Friend We live in a post-industrial age where information is the coin of the realm. Knowledge is the most valuable asset that a business owns. For most businesses, that knowledge exists primarily in the heads of the people who work there. For entrepreneurs and sole practitioners, what's in their head usually is the business. That's both limiting and dangerous. Microsoft Great Plains: Offshore Customization & Development ' Overview for Consultant When you visit department stores and see that majority of the apparels are produced in other countries, not US ' you probably do not worry about this fact. About 10 years ago, when Clinton's high tech era was at the inception ' we saw the signs of high tech professionals inflow in the USA from overseas. Nowadays the trend is reversed ' instead of importing high tech people, we are at the beginning of outsourcing to them in their overseas countries the programming workload. In this small article we'll concentrate on the Microsoft Business Solutions Great Plains customization specifics: Great Plains Dexterity (IDE and programming language), SQL programming with XML in/out bound, VBA/Modifier/Continuum, Crystal Reports, Web publishing/eCommerce The Dreaded Paper Label - Should it be Used' While paper labeling CDs and DVDs may appear to be a cost effective solution for printing on your media, there are solid reasons why you should consider other options. Freight Forwarding ERP: Microsoft Business Solutions Great Plains customization & setup ' overview Microsoft Great Plains may be recommended for international freight forwarding / transportation company. Great Plains has such features as multicurrency (Euro, Pound, Yuan, Yen, Peso, Real), Spanish, French, Brazilian Portuguese (and if needed Unicode-specific languages such as Chinese, Japanese). If you have operations in East Europe ' you can have Polish version as well as you can have several screens (SOP Entry, Inventory Item Maintenance, Customer/Vendor Maintenance, etc) translated to Russian, Lithuanian, Latvian. Plus ' if you consider Great Plains as a platform for custom tailoring and developing ' you can have reasonably priced solution for horizontal business, such as freight forwarding, cargo delivery, consignment, transportation. Let's consider industry specifics and the way to implement them in Microsoft Business Solutions Great Plains How to Make Attractive and Effective PowerPoint Presentations Microsoft PowerPoint has dramatically changed the way in which academic and business presentations are made. This article outlines few tips on making more effective and attractive PowerPoint presentations. Great Plains Dexterity ' Microsoft Great Plains Customization Overview Microsoft Business Solutions Great Plains, former Great Plains Software Dynamics and eEnterprise are Dexterity-written applications. Also small business line: Microsoft Small Business Manager or Small Business Financials is written in Dexterity and uses the same code base as Great Plains. An Introduction to .NET Framework .Net Framework is a platform or development environment to seamlessly create web-applications that are accessible through client machines from across the globe. These web-applications adopt open standards such as eXtensible Markup Language (XML), HyperText Transfer Protocol (HTTP), and Simple Object Access Protocol (SOAP) to interact with applications that are available in other platforms. Who's Watching What You Type' If someone entered your home, uninvited and installed numerous cameras and listening devices in order to monitor your activities, you would quite rightly be outraged. While such a situation, unless you are living in the Big Brother House, would be considered ridiculous, the same cannot be said for the humble home computer. Backing Up And Restoring Your MySQL Database If you've been using MySQL database to store your important data, it is imperative that you make a backup of your data to prevent any loss of data. This article shows you how to backup and restore data in your MySQL database. This process can also be used if you have to move your data to a new server. Corporate Accounting System: Microsoft Great Plains ' Overview Corporate ERP/MRP selection might be tough one, especially considering very turbulent ERP world and fierce competition between Microsoft Business Solutions (Great Plains, Navision, Axapta, MS CRM), Oracle (Oracle Financials, PeopleSoft, JD Edwards), IBM (including Lotus Domino), SAP, Microsiga (Brazil, Portugal). We recommend you, IT director of large corporation, make your home work and decide on Microsoft or Java/EJB/J2EE platform (however you should consider vendor dependence minimization, and stake on both with XML streams integration between the two). In this small article we will concentrate on Microsoft Great Plains, former Great Plains Software Dynamics/eEnterprise/Great Plains Accounting Microsoft Business Solutions VAR/Partner Selection ' Overview for IT Director/Manager/Controller Microsoft Great Plains and Microsoft CRM become more and more popular, partly because of Microsoft muscles behind them. Now Great Plains is targeted to the whole spectrum of horizontal and vertical market clientele. Small companies use Small Business Manager (which is based on the same technology ' Great Plains Dexterity dictionary and runtime), Great Plains Standard on MSDE is for small to midsize clients, and then Great Plains serves the rest of the market up to big corporations. Microsoft CRM is extremely scalable and fits to all the market niches. Microsoft CRM USA Nationwide Remote Support Remember old good days when your company probably had Great Plains Dynamics? If you are in San Francisco Bay Area ' you had local Great Plains Software partner consulting company, who served you basically coming onsite and charging you four hours minimum, even if the problem deserved 5-min fix? This was at the end of 20th century and remote support technologies were not very advanced ' Citrix was making good progress and taking market over from Symantec PCAnywhere. Today, when Microsoft Terminal Server and Citrix are remote support standards and IT department uses them to host application server for nation-wide and world-wide users, you should probably be thinking of getting remote support for your ERP and CRM systems. In this small article we'll take a look at Microsoft CRM remote support, customization, reporting, implementation and integration. Computer Phones ' Facts and Fallacies The stakes are high when considering security, privacy, and savings, and the old adage, "look before you leap" might be a more judicial approach when searching for a computer phone provider, aka VoIP (voice over internet protocol). Microsoft eCommerce Web-development: Great Plains eConnect .Net ' Highlights for Programmer In our small article we'll consider Microsoft Business Solutions Great Plains Sales Order Processing module as eCommerce backend. Plus we'll cover what is possible and impossible in eConnect and why. Microsoft Great Plains is one of the most popular ERP in the US, Canada, Australia, New Zealand, Middle East, Latin America, UK and South Africa. Due to the MBS strategy ' Great Plains Dynamics was pulled from other markets, such as continental Europe (Germany, France, Russia) ' where Navision and Axapta are the promoted and recommended solutions. If you have Navision or Axapta ' please read our publications on these products on Alba Spectrum Technologies publication site.
|
 |
| Copyright © 2009 www.dovada.net.au |
