...The Seven Layers of the OSI Model The OSI is an open networking model developed by ISO over the same time frame as TCP/IP. The Open Systems Interconnection (OSI) model has seven layers. The layers are stacked beginning with the 'lowest' (the physical) and proceeding to the 'highest' (the application). A layer serves the layer above it and is served by the layer below it. PHYSICAL LAYER The physical layer, the lowest layer of the OSI model, provides the path through which data moves among devices on the network (it specifies how a device sends and receives). Other functions of the physical layer include the conversion of signals into something that another layer can use (referred to as a bit), and adjusting the signal to allow for multiple users to use the same connection. The physical layer receives data from the data link layer, and transmits it to the wire. DATA LINK LAYER Layer two of the OSI model is the Data Link which provides a system through which network devices can share the communication channel. The data link layer provides error-free transfer of data frames from one node to another over the physical layer, allowing layers above it to assume virtually error-free transmission over the data. NETWORK LAYER Layer three, the network layer controls the operation of the subnet, deciding which physical path the data should take based on network conditions, priority of service, and other factors. This layer also handles aspects of Routing Protocols, finding the...
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...1 OSI 7 Layer ( Mr.Watt ) ( Mr.Mast ) ( Mr.Jodoi ) Network Certificate Layers Network 1. Why Network ? network. ( Why Network ? ) CCNA , CCNP , LPI , Security + , CWNA OSI 7 Layers CCIE OSI 7 Network ? share data , network copy flash drive network msn file Share file Server Internet software e-mail file netwok network network OSI 7 Layers OSI 7 Layers Internet Internetwork layer OSI OSI Open System Interconnection OSI Model 7 OSI OSI model 1.Physical Layer 2.Data Link Layer 3.Network Layer 4.Transport Layer 5.Session Layer 6.Presentation Layer 7.Application Layer OSI 7 Layers Application Application Presentation Presentation Session Session Transport Transport Network Network Data Link Data Link Physical Physical Layer 1.Physical Layer Physical Layer Connector layer bits protocol CAT5, CAT6, RJ-45 cable Lan CCNA Lan UTP Serial UTP Lan 1. Router - Lan Lan Lan ( Crossover ) PC Lan PC , Router ( Straight ) PC Hub Switch 2. Lan Router PC Lan 2.Data Link Layer Data Link Layer MAC Address ATM , MPLS Data Link Layer CCNA encapsulation encapsulation encapsulation frame decapsulation encapsulation layer Frame address protocol Ethernet , Token Ring , IEEE 802.3/202.2 , Frame Relay, FDDI,HDLC, 2 LAN VLAN Switch Trunk port encapsulation encapsulation VLAN config Trunk port cisco Switch encapsulation Port LAN WAN Mac Address Table , Switch...
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...Papers The OSI Model: Understanding the Seven Layers of Computer Networks 1-800-COURSES www.globalknowledge.com The OSI Model: Understanding the Seven Layers of Computer Networks Paul Simoneau, Global Knowledge Course Director, Network+, CCNA, CTP Introduction The Open Systems Interconnection (OSI) model is a reference tool for understanding data communications between any two networked systems. It divides the communications processes into seven layers. Each layer both performs specific functions to support the layers above it and offers services to the layers below it. The three lowest layers focus on passing traffic through the network to an end system. The top four layers come into play in the end system to complete the process. This white paper will provide you with an understanding of each of the seven layers, including their functions and their relationships to each other. This will provide you with an overview of the network process, which can then act as a framework for understanding the details of computer networking. Since the discussion of networking often includes talk of “extra layers”, this paper will address these unofficial layers as well. Finally, this paper will draw comparisons between the theoretical OSI model and the functional TCP/IP model. Although TCP/IP has been used for network communications before the adoption of the OSI model, it supports the same functions and features in a differently layered arrangement. An Overview of the OSI Model ...
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...OSI Seven Layer Model The Open System Interconnection model (OSI) defines internetworking in terms of a vertical stack of seven layers. The upper layers of the OSI model represent software that implements network services like encryption and connection management. The lower layers of the OSI model implement more primitive, hardware-oriented functions like routing, addressing, and flow control(Mitchell, 2011).The seven layers of the OSI model are - * Physical * DataLink * Network * Transport * Session * Presentation * Application Physical Layer is the first layer of the OSI model and deals with the physical aspects of the media being used to transmit the data. This layer is also responsible for bit-level transmission between network nodes. Specification examples include Ethernet, 802.3, 802.5, and Fiber Distributed Data Interface. Data Link Layer is the second layer of the OSI model and is responsible for ensuring there are data link connections between two network entities so that data can get across a specific medium and individual links. Examples of this layer include IEEE 802.3, IEEE 802.5, Token Ring, and Frame Relay. Network Layer is the third layer of the OSI model and is responsible for the packet sequencing, congestion control, and error handling. This layer also provides paths for data to transfer through the network. At the Network layer routers began to operate. Examples of this layer include the use of Internetwork Protocol (IP)...
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...Web Sites - The OSI Model and Layer Protocols NTC/362 March 9, 2015 The building of a web site begins with considering the multilayered framework of the Open System Interconnection (OSI) model or the Transmission Control Protocol/Internet Protocol (TCP/IP) model. Network models are designed to categorize all the required functionality around computer communications as well as explain the relationship and flow of information from layer to layer. These models can also be thought of as the structure for interfacing human and data networks. It is also important to think of these models existing on both ends of the networked data transmission. The end to end process can be viewed as a six step process. In step 1 people create the communication. Step 2 the application layer prepares human communication for transmission over the data network. Step 3 software and hardware convert communication to a digital format. Step 5 the application layer services initiate the data transfer. Step 5 model layers play a role in encapsulating data down the stack. Encapsulated data travels across the media to the destination. Model layers then unencapsulate the data up the stack. Lastly in step 6 the application layer receives the data from the network and prepares it for human use. The seven layers of the OSI model are 1-Physical, 2-Dat Link, 3-Network, 4-Transport, 5-Session, 6-Presentation, and 7-Application. The TCP/IP model is a four layer model. The layers of the TCP/IP model...
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...to do a good job…if you want a tutorial that just applies a couple of filters, then this tutorial is not for you! You will need to know how to use the PEN TOOL for this tutorial. (If you don’t know how to use the pen tool complete the fast tutorial found HERE first). I suggest you read through the entire tutorial first, before you begin. 1. Preparing the Layers Open your photo in Photoshop. Rename the layer “original”. If your picture is quite dark you will need to lighten it a little. The reason for this is that we will be tracing over the photo in black so we need to be able to see the lines we are creating clearly. Adjust the Brighness of the photo Image >> Adjustments >> Brightness/Contrast… Duplicate the “original” layer. Rename this new layer “top”. Create two more new layers. Place them under the “top” layer. Fill the layer closest to the “original” layer white and rename it “background”. Leave the other layer transparent and rename it “line art” Turn the visibility OFF for the “background” and “top” layers.< Visibility ON for the “line art” and “original” layers and the “line art” layer is active. See image below. (All this organisation will be explained soon). We are now set to create the line art. 2. Brush Tool Settings When creating line art you want to vary to thickness of the line (line weight). Varying the line weight emphasizes the perspective of the drawing. As lines become closer the viewers the lines get thicker. Lines taper...
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...PHOTOSHOP INSTRUCTIONS PHOTOSHOP INSTRUCTIONS 1. Open Photoshop TIPS Use the layers and ‘rasterize’ the layer for each image you use! TIPS Use the layers and ‘rasterize’ the layer for each image you use! To open a blank page:- 1. Click on File / New 2. Rename it Poster To Insert an image from your folder :- 1. File / Place and look for your image – double click on the image 2. Right click on the layer and choose rasterize layer – do this for all your images 3. Click on control and T to resize the image To get rid of the background of your image:- 1. Click on the Magic Wand tool to get rid of the background 2. CTRL and + to make bigger – use eraser to make neat To soften the edges of an image 1. Click on the layer of the image you want to change 2. Click on eraser tool and make sure the opacity is low (at the top) and rub around the edges (you can also use the smudge tool) To change colours / style of an image 1. Click on the layer of the image you want to change 2. Click on Image / Adjustments / Gradient map 3. Click on some of the others and experiment! Add Text 1. Add text 2. Right click to warp 3. Change styles of text More changes to style of text ….. Right click on the layer the text is on and choose blending options – experiment!! To add a background image 1. File / new 2. File / Place and look for your background image 3...
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...Head and shoulders is the best Shampoo against Dandruff because its market share increases year by year Did you know that your skin is the largest organ in your body – and one that’s constantly replenishing itself? It’s made up of four layers. New cells are created at the base layer and move up through the four layers over a period of 25-30 days. When they reach the surface, we shed the cells. This never stops: each day, you shed thousands of microscopic flakes of skin known as ‘squames’. Over a year, these add up to around 4kg in total! As an area of skin, the scalp is a bit different. It produces the most visible hairs – you’d find between 100,000 – 150,000 if you counted them. And if you were to measure shoulder-length hair as a single strand, it would stretch up to 30km! This warm, sheltered environment made up of loose skin flakes and hair makes an ideal home for micro-organisms. And here’s where the scalp differs again: it has a natural defence system against these organisms called sebum, a lightly greasy substance. However, one organism, has adapted to live off sebum. It’s as a consequence of this that it causes the shedding process to speed up – as quickly as four days in extreme cases. When this happens, the small flakes clump together and we see them as the flakes associated with dandruff. So while your scalp is pretty efficient at looking after itself, it sometimes needs a little help. And that’s as easy as using head & shoulders regularly...
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...Slide: 1 Presenter's Notes: Presentation regarding the university’s Disaster Recovery Plan/Enterprise Continuity Plan including: basic structures; roles within the DRP/ECP plan; areas within a company if addressed improve resilience to catastrophic events, and an employee awareness campaign. Slide 2: Presenter's notes: Presenter's notes: The presentation will cover several areas dealing with the university’s ability to prepare for an emergency or catastrophic event. The areas covered include: 1. Personnel roles within a disaster recovery and emergency continuity plan 2. Areas within the university that when properly addressed provide resilience to operational disturbances 3. Outline of a DRP/ECP training program. 4. Areas of the emergency plans that will improve by input from outside vendors. 5. The creation and execution of the plan to make employees aware of their roles in the DRP/ECP plan while confirming their understanding A1. DRP/ECP Roles Slide 3: Presenter's Notes: The responsibility of the emergency management team is to coordinate a series of teams within the university. First the perimeter security team is responsible for maintaining the physical security of the university’s property during an emergency. Second the technical support team must define operational procedures to create preparedness for an emergency; procedures to execute during an emergency situation, and procedures for catastrophic events to allow the business to function...
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...Architectural Layer Standards The CAD Layer Guidelines are organized as hierarchy. This arrangement accommodates expansion and addition 0f user-defined extensions to the layer list. Layer names are alphanumeric and use abbreviations that are easy to remember. This legibility is particularly important when CAD files are distributed among architects, consultants, and clients. Layer names consist of a Discipline Code-Major Group-Minor Group-Status Field. The format for the CAD Standard is as follows: Discipline Code Discipline is the primary method of classification for layer names. The discipline code provides a path back to the originator of the data and provides a logical categorization of CAD information. The discipline code is intended primarily to identify the author of the graphic information. Thus, a structural column placed by an architect would be A-COLS rather than S-COLS. The existence of both sets of information can in fact indicate the need for coordination. The Discipline Code is a one or two-character field with the second character either a hyphen or a user-defined modifier. The discipline codes are listed below. A Architectural M Mechanical C Civil P Plumbing E Electrical Q Equipment F Fire Protection R Resource G General S Structural H Hazardous Materials T Telecommunications I Interiors X Other L Landscape Z Contractor/shop Drawings Major Group The Major Group designation identifies the building system. This field must contain...
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...The Data Link Layer and Physical Layer OSI Model: The Open Framework Interconnection display characterizes a systems administration structure to execute conventions in layers, with control go starting with one layer then onto the next. It is fundamentally utilized today as an instructing device. It reasonably separates PC arrange design into 7 layers in a coherent movement. The lower layers manage electrical signs, pieces of paired information, and directing of these information crosswise over systems. More elevated amounts cover organize solicitations and reactions, portrayal of information, and system conventions as observed from a client's perspective. The OSI demonstrate was initially considered as a standard engineering for building system frameworks and to be sure, numerous mainstream organize advancements today mirror the layered outline of OSI...
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...The TCP/IP Model Mr. Randy Vogl Gus Perez 19593003 The TCP/IP network model Exercise 3.3.1 What are the distinct differences between OSI and TCP/IP models? TCP refers to Transmission Control Protocol. OSI refers to Open Systems Interconnection. Model TCP/IP is developed on points toward a model the internet. TCP/IP has 4 layers. OSI has 7 layers. TCP/IP more reliable than OSI OSI has strict boundaries; TCP/IP does not have very strict boundaries. TCP/IP follow a horizontal approach. OSI follows a vertical approach. In the application layer, TCP/IP uses both session and presentation layer. OSI uses different session and presentation layers. TCP/IP developed protocols then model. OSI developed model then protocol. TCP/IP offers support for connectionless communication within the network layer. In the network layer, OSI supports both connectionless and connection-oriented communication. TCP/IP is protocol dependent. OSI is protocol independent. http://www.differencebetween.net/technology/internet/difference-between-osi-and-tcp-ip-model/ Read more: Difference between OSI and TCP IP Model | Difference Between | Difference between OSI vs TCP IP Model http://www.differencebetween.net/technology/internet/difference-between-osi-and-tcp-ip-model/#ixzz3f4nyPzTU TCP/IP model protocols and functions. Exercise 3.3.2 Identify the layer in which each protocol resides according to the TCP/IP model. Using figure 3.4 from the Lab manual, Telnet, FTP, SMTP, DNS, RIP, SNMP...
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...engineering, the whole networking concept is divided into multiple layers. Each layer is involved in some particular task and is independent of all other layers. But as a whole the almost all networking task depends on all of these layers. Layers share data between them and they depend on each other only to take input and give output. In layered architecture of Network Models, one whole network process is divided into small tasks. Each small task is then assigned to a particular layer which works dedicatedly to process the task only. Every layer does only specific work. I have chooses application layer from the OSI model because the world experiences the Internet through the use of the World Wide Web, e-mail, and file-sharing programs. These applications, as well as others, provide the human interface to the underlying network, allowing you to send and receive information with relative ease. Most of the applications are intuitive; they can be accessed and used without the need to know how they work. As we continue to study the world of networking, it becomes more important to know how an application is able to format, transmit, and interpret messages that are sent and received across the network. INTRODUCTION Application layer is the highest most layers in OSI and TCP/IP layered model and this layer exists in both layered Models because of its significance which is interacting with user and user applications. This layer is for applications which are involved in communication system...
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...com). Protocols that exist for wireless communications such as wireless session protocol, wireless transaction protocol, wireless transport layer security, and wireless datagram protocol each covering different aspects of the communications model (Protocols.com). Just like wired and TCP/IP communications, wired communication protocols exist in a wireless communications OSI model (Protocols.com). The wireless communications OSI model is divided into the following layers; application layer, session layer, transaction layer, security layer, transport layer (Protocols.com). Each layer of the wireless communications OSI model has is associated protocols. The necessity for different protocols for wireless communications comes from this “WAP Stack” which is the model for wireless data transfer (Protocols.com). Each layer of the model is governed by different protocols, and are divided as follows. * Application Layer Protocols * WAE or Wireless Application Environment * WTA or Wireless Telephony Application (Protocols.com) * Session Layer Protocols * WSP or Wireless Session Protocol (Protocols.com) * Transaction Layer Protocols * WTP or Wireless Transaction Protocol (Protocols.com) * Security Layer Protocols * WTLS or Wireless Transport Layer Security (Protocols.com) * Transport Layer Protocols * WDP or Wireless Datagram Protocol (Protocols.com) Protocols are necessary for communications between systems, different...
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...2 The OSI model. It actually shows the process. 3.1.3 Physical, Data, Link, Network, Transport, Session and Presentation. 3.1.4 If its too general the reader wont understand completely. And if its too focused or granular on details it will bore the reader. 3.2.1 Physical – Device Data Link – Physical address Network – Path determination Transport – End to end connections Session – internet Presentation – typing data Application – games, downloads ApplicationPresentationSession | Data | Transport | Segment | Network | Packet | Data Link | Frame | Physical | Bit | 3.2.2 3.2.3 First the receiving computer synchronizes with the digital signal by reading binary numbers. After synchronizing is complete and it gets the whole frame and passes it to the layer above it which is the Data Link layer. Second the Data Link layer will do a Cyclic Redundancy Check (CRC) on the frame. Checking for errors and then strip off any information or header which was put on by the remote systems Data Link layer and pass the rest to the Network layer. Third the Network layer checks the IP address and if it matches the Network layer header is stripped off from the packet and passed to the Transport layer. Fourth the Transport layer processes the segment and rebuilds the data stream and acknowledges to the transmitting computer that it received each piece. Then sends the data stream to the upper layer Application...
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