title
The OSI Model Demystified

description
Follow the Insanity at: https://www.FailedNormal.com Downloadable Podcasts at: https://failednormal.podbean.com iTunes: https://itunes.apple.com/us/podcast/failed-normal/id1349818284?mt=2 Info Level: Beginner Date Created: July 9, 2010 Length of Class: 18 Minutes Tracks Networking Prerequisites Introduction to Networking Purpose of Class This class explains the OSI Model for technicians Topics Covered The OSI Model Class Notes Layer 7 -- Application Layer -- The layer users interact with Layer 6 -- Presentation Layer -- Generally the layer the Operating System is on Layer 5 -- Session Layer -- The layer that controls the communication session between two computers Layer 4 -- Transport Layer -- The layer that controls Windowing and other tasks related to communication Layer 3 -- Network Layer -- The layer that Routers and IP addresses operate at Layer 2 -- Data Link Layer -- The layer that Switches, MAC Addresses and ARP reside at Layer 1 -- Physical Layer -- The layer that cabling resides on Resources Wikipedia

detail
{'title': 'The OSI Model Demystified', 'heatmap': [{'end': 373.837, 'start': 239.571, 'weight': 0.881}], 'summary': "'the osi model demystified' explores the osi model, highlighting its usefulness in networking by breaking down network communication into seven logical layers, emphasizing its relevance to networking issues, and noting that 95% of networking problems are layer one issues.", 'chapters': [{'end': 90.029, 'segs': [{'end': 90.029, 'src': 'embed', 'start': 44.91, 'weight': 0, 'content': [{'end': 54.352, 'text': "To understand, all the OSI model is, is it's just a logical model for how network systems are supposed to communicate to each other.", 'start': 44.91, 'duration': 9.442}, {'end': 63.095, 'text': 'So basically, all the model does is break down the different components of network communication and kind of slot them into layers.', 'start': 54.832, 'duration': 8.263}, {'end': 65.194, 'text': 'So you may hear of the physical layer.', 'start': 63.515, 'duration': 1.679}, {'end': 71.377, 'text': 'So the physical layer is all the wiring, all the physical stuff that connects computers together.', 'start': 65.235, 'duration': 6.142}, {'end': 74.939, 'text': 'you then have layer two, the data link layer.', 'start': 72.217, 'duration': 2.722}, {'end': 77.621, 'text': 'This is the layer where switching occurs.', 'start': 75.279, 'duration': 2.342}, {'end': 84.926, 'text': 'So all those switches that you plug your computers into, all of what they do resides on layer two.', 'start': 77.701, 'duration': 7.225}, {'end': 90.029, 'text': 'So, basically, the OSI model is seven logical layers.', 'start': 85.366, 'duration': 4.663}], 'summary': 'The osi model is a logical model for network communication, consisting of seven layers, including physical and data link layers.', 'duration': 45.119, 'max_score': 44.91, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI44910.jpg'}], 'start': 5.575, 'title': 'Understanding osi model', 'summary': 'Demystifies the osi model, highlighting its usefulness in networking by breaking down network communication into seven logical layers, making it easier to understand and manage.', 'chapters': [{'end': 90.029, 'start': 5.575, 'title': 'Understanding osi model', 'summary': 'Demystifies the osi model, highlighting its usefulness in networking by breaking down network communication into seven logical layers, making it easier to understand and manage.', 'duration': 84.454, 'highlights': ['The OSI model is an incredibly useful tool that breaks down network communication into logical layers, making life easier for technologists.', 'It consists of seven logical layers including the physical layer for wiring, the data link layer for switching, and others, making it easier to understand and manage network systems.']}], 'duration': 84.454, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI5575.jpg', 'highlights': ['The OSI model is an incredibly useful tool that breaks down network communication into logical layers, making life easier for technologists.', 'It consists of seven logical layers including the physical layer for wiring, the data link layer for switching, and others, making it easier to understand and manage network systems.']}, {'end': 847.159, 'segs': [{'end': 133.798, 'src': 'embed', 'start': 109.449, 'weight': 1, 'content': [{'end': 116.297, 'text': 'Instead of fixing things, they use the OSI model to narrow in and figure out exactly what they have to build for.', 'start': 109.449, 'duration': 6.848}, {'end': 120.353, 'text': "Like I say, it's not that hard, it's not that complicated.", 'start': 118.092, 'duration': 2.261}, {'end': 123.174, 'text': 'This will be a short and sweet, simple little class.', 'start': 120.373, 'duration': 2.801}, {'end': 130.176, 'text': 'This class on the OSI model is focused from the IT, from the technologist standpoint, so for troubleshooting and such.', 'start': 123.234, 'duration': 6.942}, {'end': 133.798, 'text': "If you're a programmer, well, I don't know, take a programming class.", 'start': 130.637, 'duration': 3.161}], 'summary': 'The class on the osi model focuses on troubleshooting for technologists, offering a simple, short, and sweet approach.', 'duration': 24.349, 'max_score': 109.449, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI109449.jpg'}, {'end': 191.93, 'src': 'embed', 'start': 159.226, 'weight': 4, 'content': [{'end': 161.267, 'text': 'Okay, so the OSI model.', 'start': 159.226, 'duration': 2.041}, {'end': 167.168, 'text': 'This is just O-S-I model.', 'start': 161.307, 'duration': 5.861}, {'end': 172.51, 'text': 'Okay, the OSI model is made up of seven layers.', 'start': 167.849, 'duration': 4.661}, {'end': 183.324, 'text': 'The layers from top to bottom are for what is closest to the end user, so what the user is interacting with,', 'start': 173.93, 'duration': 9.394}, {'end': 186.646, 'text': 'all the way down to actually shooting the information out on the network.', 'start': 183.324, 'duration': 3.322}, {'end': 191.93, 'text': 'So the first layer, the top layer, layer seven, is called the application layer.', 'start': 186.946, 'duration': 4.984}], 'summary': 'Osi model consists of 7 layers, with layer 7 being the application layer.', 'duration': 32.704, 'max_score': 159.226, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI159226.jpg'}, {'end': 373.837, 'src': 'heatmap', 'start': 239.571, 'weight': 0.881, 'content': [{'end': 243.594, 'text': 'This layer is basically the layer that the operating system is on.', 'start': 239.571, 'duration': 4.023}, {'end': 250.1, 'text': 'So you interact with the application layer that sends information down to the presentation layer,', 'start': 243.835, 'duration': 6.265}, {'end': 254.243, 'text': 'which is generally the layer that the operating system works on.', 'start': 250.1, 'duration': 4.143}, {'end': 258.747, 'text': "Underneath the presentation layer, you have what's called the session layer.", 'start': 255.404, 'duration': 3.343}, {'end': 268.622, 'text': 'The session layer is the layer that deals with the communication creating a session between the two computers.', 'start': 260.079, 'duration': 8.543}, {'end': 272.282, 'text': 'So, if you are going to a website,', 'start': 269.162, 'duration': 3.12}, {'end': 281.544, 'text': "basically your computer at the session layer has to create a session with the web server that you're trying to access to get data from.", 'start': 272.282, 'duration': 9.262}, {'end': 283.725, 'text': "So that's what the session layer does.", 'start': 281.704, 'duration': 2.021}, {'end': 290.006, 'text': "The session layer actually creates the session between your computer and the computer you're trying to get information from.", 'start': 283.765, 'duration': 6.241}, {'end': 290.528, 'text': 'information from.', 'start': 290.026, 'duration': 0.502}, {'end': 294.426, 'text': 'Underneath that is called the transport layer.', 'start': 291.473, 'duration': 2.953}, {'end': 306.374, 'text': 'The transport layer, this layer is what decides how much information should be sent at one time.', 'start': 297.608, 'duration': 8.766}, {'end': 313.72, 'text': "So, when you're communicating with a website, this is the layer that decides how much information you will communicate to the website,", 'start': 306.775, 'duration': 6.945}, {'end': 315.441, 'text': 'how much information will be communicated back.', 'start': 313.72, 'duration': 1.721}, {'end': 318.723, 'text': 'This deals with the transport of the data back and forth.', 'start': 315.801, 'duration': 2.922}, {'end': 320.625, 'text': 'You then have the network layer.', 'start': 319.464, 'duration': 1.161}, {'end': 329.514, 'text': 'The network layer is the layer that routers operate at.', 'start': 325.27, 'duration': 4.244}, {'end': 336.001, 'text': "So you know your router that you have at home, or if you've been doing networking technology, you know a router.", 'start': 329.754, 'duration': 6.247}, {'end': 339.224, 'text': 'Routers operate at the network level.', 'start': 336.701, 'duration': 2.523}, {'end': 342.908, 'text': 'So your IP address is at the network level.', 'start': 339.324, 'duration': 3.584}, {'end': 349.154, 'text': "Underneath this, make sure you're still on the screen, yep, you have the data link layer.", 'start': 343.909, 'duration': 5.245}, {'end': 356.472, 'text': 'The data link layer is the layer that switches operate on.', 'start': 352.671, 'duration': 3.801}, {'end': 362.094, 'text': 'So again, all the computers on a network get plugged into a switch so that they can talk to each other.', 'start': 357.092, 'duration': 5.002}, {'end': 373.837, 'text': 'That happens, that layer is called the data link layer, and then underneath that, the final layer, layer one, is called the physical layer.', 'start': 363.414, 'duration': 10.423}], 'summary': 'The networking layers include application, presentation, session, transport, network, data link, and physical layers, each with specific functions.', 'duration': 134.266, 'max_score': 239.571, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI239571.jpg'}, {'end': 486.803, 'src': 'embed', 'start': 454.733, 'weight': 0, 'content': [{'end': 456.514, 'text': 'Basically, This is cable.', 'start': 454.733, 'duration': 1.781}, {'end': 458.356, 'text': 'This is Cat5 cable.', 'start': 456.634, 'duration': 1.722}, {'end': 459.977, 'text': "That's what the physical layer is.", 'start': 458.436, 'duration': 1.541}, {'end': 469.105, 'text': 'As one senior network administrator told me, 95% of all networking problems are layer one problems.', 'start': 461.158, 'duration': 7.947}, {'end': 471.428, 'text': 'Basically, somebody unplugged the damn cable.', 'start': 469.386, 'duration': 2.042}, {'end': 472.388, 'text': 'Pretty simple.', 'start': 471.968, 'duration': 0.42}, {'end': 479.636, 'text': 'Now above the physical layer, so this is how things are connected, above that is the data link layer.', 'start': 473.189, 'duration': 6.447}, {'end': 482.098, 'text': 'This is where switches reside.', 'start': 479.796, 'duration': 2.302}, {'end': 486.803, 'text': "So we're going to have a class on switches to explain how all this works better.", 'start': 482.579, 'duration': 4.224}], 'summary': '95% of networking problems are layer one problems, often due to cable issues. above physical layer is data link layer with switches.', 'duration': 32.07, 'max_score': 454.733, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI454733.jpg'}], 'start': 90.029, 'title': 'Understanding osi model', 'summary': 'Explains the osi model, consisting of seven layers and their functions, emphasizing its relevance to networking issues, with a notable statistic of 95% of networking problems being layer one problems.', 'chapters': [{'end': 153.065, 'start': 90.029, 'title': 'Understanding osi model for troubleshooting', 'summary': 'Discusses the osi model and its relevance for troubleshooting network problems, emphasizing its practical application for it professionals and its contrast with the approach used by programmers.', 'duration': 63.036, 'highlights': ['The OSI model is used to troubleshoot network problems and zero in on the specific issue, making it easier for IT professionals to fix the problem.', 'Understanding the layers of the OSI model helps in focusing on individual network problems and addressing them effectively.', 'The OSI model provides a framework for technologists to troubleshoot and fix network issues, offering practical benefits for IT professionals.']}, {'end': 847.159, 'start': 159.226, 'title': 'Understanding the osi model', 'summary': 'Explains the osi model, which consists of seven layers from application layer to physical layer, with emphasis on their functions and relevance to networking issues, with a notable statistic of 95% of networking problems being layer one problems.', 'duration': 687.933, 'highlights': ['The OSI model consists of seven layers from application layer to physical layer, each with specific functions and responsibilities. The chapter explains the seven layers of the OSI model, including their specific functions and responsibilities.', '95% of all networking problems are layer one problems, primarily related to physical layer issues such as wiring, cabling, and connectivity. A notable statistic is mentioned where 95% of networking problems are attributed to layer one problems, primarily dealing with physical layer issues such as wiring, cabling, and connectivity.', 'The importance and functions of each layer in the OSI model are detailed, with a particular emphasis on their relevance to networking issues and troubleshooting. The chapter emphasizes the importance and functions of each layer in the OSI model, particularly in relation to networking issues and troubleshooting.']}], 'duration': 757.13, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI90029.jpg', 'highlights': ['95% of all networking problems are layer one problems, primarily related to physical layer issues such as wiring, cabling, and connectivity.', 'The OSI model is used to troubleshoot network problems and zero in on the specific issue, making it easier for IT professionals to fix the problem.', 'Understanding the layers of the OSI model helps in focusing on individual network problems and addressing them effectively.', 'The OSI model provides a framework for technologists to troubleshoot and fix network issues, offering practical benefits for IT professionals.', 'The OSI model consists of seven layers from application layer to physical layer, each with specific functions and responsibilities.', 'The chapter explains the seven layers of the OSI model, including their specific functions and responsibilities.', 'The importance and functions of each layer in the OSI model are detailed, with a particular emphasis on their relevance to networking issues and troubleshooting.']}, {'end': 1114.842, 'segs': [{'end': 873.953, 'src': 'embed', 'start': 847.519, 'weight': 0, 'content': [{'end': 854.725, 'text': "All it's trying to do is what I want you to understand, like I said, it's a professional tech, you know, I've done this a lot in the real world.", 'start': 847.519, 'duration': 7.206}, {'end': 865.629, 'text': 'What models like this try to do for you as a technician is when you walk in to a problem, when you walk into a situation,', 'start': 856.145, 'duration': 9.484}, {'end': 867.43, 'text': 'you have no idea where to start.', 'start': 865.629, 'duration': 1.801}, {'end': 873.953, 'text': 'And this tries to give you just a model for how to think about the problem.', 'start': 867.77, 'duration': 6.183}], 'summary': 'Professional tech models help technicians approach problems systematically.', 'duration': 26.434, 'max_score': 847.519, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI847519.jpg'}, {'end': 1014.157, 'src': 'embed', 'start': 982.444, 'weight': 3, 'content': [{'end': 985.905, 'text': 'If you have a network layer problem, there, IP addresses.', 'start': 982.444, 'duration': 3.461}, {'end': 992.72, 'text': "That'll link layer, this is where all the switching, ARP and MAC addresses happen, and then physical layer, all the physical cable stuff.", 'start': 987.225, 'duration': 5.495}, {'end': 994.364, 'text': 'It is really that simple.', 'start': 993.201, 'duration': 1.163}, {'end': 1003.989, 'text': "So that's really all there is to the OSI model.", 'start': 1000.566, 'duration': 3.423}, {'end': 1014.157, 'text': 'The OSI model is just a logical model to allow you to think about problems and try to decide where the problem may be.', 'start': 1004.109, 'duration': 10.048}], 'summary': 'The osi model consists of network, link, and physical layers, simplifying network troubleshooting.', 'duration': 31.713, 'max_score': 982.444, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI982444.jpg'}, {'end': 1080.416, 'src': 'embed', 'start': 1055.527, 'weight': 7, 'content': [{'end': 1064.609, 'text': "don't know the specific problem, but you have a better idea of where the problem is, basically using this process to divide everything down.", 'start': 1055.527, 'duration': 9.082}, {'end': 1067.87, 'text': 'Again, the OSI model is not a huge issue.', 'start': 1065.029, 'duration': 2.841}, {'end': 1073.811, 'text': "I know a lot of people pull their hair out when they're trying to learn this, because a lot of times you have to learn this for tests.", 'start': 1067.99, 'duration': 5.821}, {'end': 1075.732, 'text': 'Again, I had to learn this for certification.', 'start': 1073.891, 'duration': 1.841}, {'end': 1080.416, 'text': "But if you do have to learn it, don't just forget it at the end of the day.", 'start': 1076.952, 'duration': 3.464}], 'summary': 'Emphasize the importance of understanding the osi model for tests and certification.', 'duration': 24.889, 'max_score': 1055.527, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI1055527.jpg'}, {'end': 1114.842, 'src': 'embed', 'start': 1098.414, 'weight': 6, 'content': [{'end': 1100.795, 'text': "So that's basically all the OSI model is.", 'start': 1098.414, 'duration': 2.381}, {'end': 1101.896, 'text': 'I hope you understand it.', 'start': 1100.815, 'duration': 1.081}, {'end': 1104.897, 'text': 'Like I say, very useful, very, very, very, very, very, very useful.', 'start': 1102.076, 'duration': 2.821}, {'end': 1108.599, 'text': "As you know, I'm Eli, the Computer Guy, over here for Everyman IT.", 'start': 1105.738, 'duration': 2.861}, {'end': 1110.9, 'text': 'As always, I hope you understood this class.', 'start': 1109.019, 'duration': 1.881}, {'end': 1112.801, 'text': 'Again, important class, very, very useful.', 'start': 1111.04, 'duration': 1.761}, {'end': 1114.842, 'text': 'I look forward to seeing you at the next class.', 'start': 1113.481, 'duration': 1.361}], 'summary': 'The osi model is very useful. -eli', 'duration': 16.428, 'max_score': 1098.414, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI1098414.jpg'}], 'start': 847.519, 'title': 'Professional tech troubleshooting model and osi model', 'summary': 'Discusses the role of a professional tech model in troubleshooting various technical issues and explains the osi model, which divides network communication into seven layers, aiding in network issue troubleshooting.', 'chapters': [{'end': 943.601, 'start': 847.519, 'title': 'Professional tech troubleshooting model', 'summary': 'Discusses the role of a professional tech model in providing a structured approach to troubleshooting various technical issues, offering a starting point for analysis and solution finding in complex situations involving server room outages, email routing issues, and web server accessibility problems.', 'duration': 96.082, 'highlights': ['The professional tech model provides a structured approach to troubleshooting various technical issues, offering a starting point for analysis and solution finding in complex situations involving server room outages, email routing issues, and web server accessibility problems.', 'It assists technicians in breaking down the possible reasons for technical problems, which can range from 10 to 30 different reasons, enabling a more systematic approach to fixing issues.', 'The model serves as a guide for technicians when they encounter scenarios where they have no idea where to start, providing a framework for thinking about the problem and initiating the troubleshooting process.', "It is highlighted that the model is not aimed at addressing simple user-related issues, such as a 12-year-old's inability to access a specific website, but rather focuses on complex technical problems affecting thousands of users, such as email routing and web server accessibility issues."]}, {'end': 1114.842, 'start': 943.601, 'title': 'Understanding osi model', 'summary': 'Explains the osi model, which divides network communication into seven layers, and how it helps in troubleshooting network issues by narrowing down the problem area based on specific symptoms and lights on the server, making it a useful tool for network technicians.', 'duration': 171.241, 'highlights': ['The OSI model divides network communication into seven layers, from the application layer at the top where the user interacts with the system, down to the physical layer dealing with physical cable connections. 5', 'The OSI model helps in troubleshooting network issues by allowing technicians to narrow down the problem area based on specific symptoms and lights on the server. 4', 'It is emphasized that understanding the OSI model is useful for network technicians and can help in identifying the source of network problems, even if the specific issue is not known. 3', 'The speaker, Eli, highlights the practical application of the OSI model, stating it as a valuable tool for breaking down and identifying network problems during his 12 years of experience as a technician. 2', 'The speaker emphasizes the usefulness of the OSI model in troubleshooting network issues and encourages the audience to retain and apply this knowledge beyond certification exams. 1']}], 'duration': 267.323, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/HEEnLZV2wGI/pics/HEEnLZV2wGI847519.jpg', 'highlights': ['The professional tech model provides a structured approach to troubleshooting various technical issues, offering a starting point for analysis and solution finding in complex situations involving server room outages, email routing issues, and web server accessibility problems.', 'The model assists technicians in breaking down the possible reasons for technical problems, enabling a more systematic approach to fixing issues, which can range from 10 to 30 different reasons.', 'The model serves as a guide for technicians when they encounter scenarios where they have no idea where to start, providing a framework for thinking about the problem and initiating the troubleshooting process.', 'The OSI model divides network communication into seven layers, from the application layer at the top where the user interacts with the system, down to the physical layer dealing with physical cable connections.', 'The OSI model helps in troubleshooting network issues by allowing technicians to narrow down the problem area based on specific symptoms and lights on the server.', 'Understanding the OSI model is useful for network technicians and can help in identifying the source of network problems, even if the specific issue is not known.', 'The speaker, Eli, highlights the practical application of the OSI model, stating it as a valuable tool for breaking down and identifying network problems during his 12 years of experience as a technician.', 'The speaker emphasizes the usefulness of the OSI model in troubleshooting network issues and encourages the audience to retain and apply this knowledge beyond certification exams.']}], 'highlights': ['The OSI model is an incredibly useful tool that breaks down network communication into logical layers, making life easier for technologists.', 'The OSI model consists of seven logical layers including the physical layer for wiring, the data link layer for switching, and others, making it easier to understand and manage network systems.', '95% of all networking problems are layer one problems, primarily related to physical layer issues such as wiring, cabling, and connectivity.', 'The OSI model is used to troubleshoot network problems and zero in on the specific issue, making it easier for IT professionals to fix the problem.', 'Understanding the layers of the OSI model helps in focusing on individual network problems and addressing them effectively.', 'The OSI model provides a framework for technologists to troubleshoot and fix network issues, offering practical benefits for IT professionals.', 'The OSI model consists of seven layers from application layer to physical layer, each with specific functions and responsibilities.', 'The chapter explains the seven layers of the OSI model, including their specific functions and responsibilities.', 'The importance and functions of each layer in the OSI model are detailed, with a particular emphasis on their relevance to networking issues and troubleshooting.', 'The professional tech model provides a structured approach to troubleshooting various technical issues, offering a starting point for analysis and solution finding in complex situations involving server room outages, email routing issues, and web server accessibility problems.', 'The model assists technicians in breaking down the possible reasons for technical problems, enabling a more systematic approach to fixing issues, which can range from 10 to 30 different reasons.', 'The model serves as a guide for technicians when they encounter scenarios where they have no idea where to start, providing a framework for thinking about the problem and initiating the troubleshooting process.', 'The OSI model divides network communication into seven layers, from the application layer at the top where the user interacts with the system, down to the physical layer dealing with physical cable connections.', 'The OSI model helps in troubleshooting network issues by allowing technicians to narrow down the problem area based on specific symptoms and lights on the server.', 'Understanding the OSI model is useful for network technicians and can help in identifying the source of network problems, even if the specific issue is not known.', 'The speaker, Eli, highlights the practical application of the OSI model, stating it as a valuable tool for breaking down and identifying network problems during his 12 years of experience as a technician.', 'The speaker emphasizes the usefulness of the OSI model in troubleshooting network issues and encourages the audience to retain and apply this knowledge beyond certification exams.']}