How to Troubleshoot A Network Using the OSI Model - Part 1
I.T professionals usually approach any network problem or ‘troubleshooting' from the OSI (Open System Interconnection) approach. An OSI implements protocols in layers, allowing you to troubleshoot systematically layer by layer.
When troubleshooting using the OSI model, you can start from the very beginning, layer 1 and move upwards; start at the top, going from layer 7 down to 1, or start troubleshooting from the layer that you believe is the problem and then move in your chosen direction. Either way you choose to work will get you where you want, but most technicians opt starting from layer 1 just because it's easier to start with the basics first.
Start off on Layer 1, the ‘physical layer', the layer that is focused on the media, signal and transmission. It is whatever goes through or operates in the network at an electrical or mechanical level. This would mean you would be troubleshooting cables, physical hardware and other devices. Troubleshooting this layer will allow you to find if it is a basic physical problem – for most I.T technicians a good place to start.
Jump to Layer 2, if you have found no direct physical problem as Layer 2 is the data link layer. Layer 2 essentially provides the way or means to transfer data between items in the network and handles/manages errors that occur in the first layer. Layer 2 is made up of 2 smaller sub-layers, the Media access Control (MAC) that grants the means of access to the data from a computer on the network and the Logic Link Control (LLC) which controls errors in the physical layer, flow control and frame synchronization (the process by which incoming signals or sequences are identified). It allows at one time for several protocols to exist together in the network, as well as to be transported to its destination.
This layer can be troubleshooted in Windows using the ARP command. The Address Resolution Protocol or ARP, is an IP protocol used for mapping the internet protocol address into a physical address, or in technical terms a MAC address. Once specified and recognised the network device responds with the address. From this you will determine the unique hardware address and identify any issues occurring between software and hardware, or other problems occurring at the 2nd layer.
If you want to find out more on how to troubleshoot a network using the OSI model, look out for part 2 of How to Troubleshoot A Network Using the OSI Model. Furthermore, if you are interested in learning more about troubleshooting, have a look at computer based training for I.T technician certifications, such as the CompTIA A+ certificationand CompTIA Network+. Visit www.cvision.co.uk for more information.
When troubleshooting using the OSI model, you can start from the very beginning, layer 1 and move upwards; start at the top, going from layer 7 down to 1, or start troubleshooting from the layer that you believe is the problem and then move in your chosen direction. Either way you choose to work will get you where you want, but most technicians opt starting from layer 1 just because it's easier to start with the basics first.
Start off on Layer 1, the ‘physical layer', the layer that is focused on the media, signal and transmission. It is whatever goes through or operates in the network at an electrical or mechanical level. This would mean you would be troubleshooting cables, physical hardware and other devices. Troubleshooting this layer will allow you to find if it is a basic physical problem – for most I.T technicians a good place to start.
Jump to Layer 2, if you have found no direct physical problem as Layer 2 is the data link layer. Layer 2 essentially provides the way or means to transfer data between items in the network and handles/manages errors that occur in the first layer. Layer 2 is made up of 2 smaller sub-layers, the Media access Control (MAC) that grants the means of access to the data from a computer on the network and the Logic Link Control (LLC) which controls errors in the physical layer, flow control and frame synchronization (the process by which incoming signals or sequences are identified). It allows at one time for several protocols to exist together in the network, as well as to be transported to its destination.
This layer can be troubleshooted in Windows using the ARP command. The Address Resolution Protocol or ARP, is an IP protocol used for mapping the internet protocol address into a physical address, or in technical terms a MAC address. Once specified and recognised the network device responds with the address. From this you will determine the unique hardware address and identify any issues occurring between software and hardware, or other problems occurring at the 2nd layer.
If you want to find out more on how to troubleshoot a network using the OSI model, look out for part 2 of How to Troubleshoot A Network Using the OSI Model. Furthermore, if you are interested in learning more about troubleshooting, have a look at computer based training for I.T technician certifications, such as the CompTIA A+ certificationand CompTIA Network+. Visit www.cvision.co.uk for more information.
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