Troubleshooting Using The OSI Model
"Warranty void if removed"
"Visit your local Genius to fix all your problems!"
"I've re-installed your OS. That'll be $A gazillion.
Ever heard these before? Now you can laugh in their face and keep all your money! All that Genius is going to do is try to replace your Apple device, and reinstalling your Operating System, though helpful, shouldn't need to happen! The technology was developed by a human, it can be solved by one too. Any problems you have can be solved if they are isolated into simple steps. The OSI model is a 7 layer standard that pretty well encompasses all the categories that can fail. Let's take a look at them and see if you can determine what is wrong with your device before taking a step out of your house!
In this article, I help briefly identify what each layer of the OSI model are, and where you could start looking. This is not a detailed guide, but simply to help understand what you would use the OSI model for in a practical sense.
Layer 1 | Physical Layer
The physical layer of the OSI model is exactly as the name implies; the physical parts of the device. The first step in basic troubleshooting should be the easiest, as this is where most problems can be fixed. The things you can touch are usually the most vulnerable to damage, but also the easiest problems to see.
The first step to troubleshooting just about every problem with your computer, device, or electrical item:
- Unplug that cable and plug it back in. Check that your cables are plugged in
- Try a second cable to replace the first
- Check for kinks, shorts, loss of quality, dust, or faulty parts
- Literally anything you can touch on the physical device.
- Power Cycle (Turn it off and back on again)
- Try another Computer
- Duplicate your setup. If the problem persists on another computer, it's the program or collection of programs conflicting with each other.
- If the problem does not persist, it is a single machine or specific user issue. Try uninstalling the software in question and see if problems persist.
Layer 2 | Data Link
Troubleshooting on Layer 2 would mean to troubleshoot your connection to the home network, or Enterprise LAN depending on your specific application. This does not mean getting to the internet, just your connectivity or ability to connect to specific machines' MAC address, rather than IP address.
To troubleshoot on Layer 2:
- Check if the Network Interface Card (NIC) is bad
- Unplug the current network cable and connect into a nearby computer
- If second computer works, much like Layer 1, narrows it down to the single host computer.
- If it doesn't work on both computers, this means the cable is bad. Return to Layer 1.
- If on wireless, try a direct connection
- This eliminates a bad radio and any additional complications that Wifi introduces.
- If you can get a direct connection, log into the router and access its wireless settings.
- If wireless does not work, and no option exists to connect it directly, try a power cycle. The connection should reset.
- If other wireless networks can be seen, but you cannot connect to your home network, try:
- Restarting the router
- Directly typing in the name of your SSID when connecting
- Hard-reset your router by holding the reset button for at least 20 seconds
- Check your wireless settings, ensure SSID broadcast is turned on.
- On Windows 10 machines, sometimes the wireless adapter driver just needs a reset. Try right-clicking the wireless icon in the taskbar and running the troubleshooter. This may be the one time the troubleshooter actually fixes the problem!
- Right-click the network connection icon in the taskbar and open Network and Sharing Options
- Open Change Adapter Options
- Right-click your adapter and disable it, then re-enable it.
- Another thing to check is the static IP. Sometimes allowing DHCP and then assigning a static IP as the one dynamically assigned allows the router to add the new IP address in its ARP table and keep it there.
- Check for IP address conflicts. If your computer is statically assigned an IP (Meaning, YOU tell your computer what address to use) then try running a command prompt and typing in "arp -a" on a working computer on the network.
ARP stands for Address Resolution Protocol. This is a list of addresses that is stored on your workstation to make future connections faster. Similar to storing a contact in your phone, you no longer have to manually type in the phone number to make a call. This list will only populate with computers where a previous connection has been made, so do a quick ping of a specific address first and then run an "arp -a" again and you should see that machine.
Layer 3 | Network
Can you access the internet?
Can you access shared drives?
Can you see other computers, printers, or devices on the network?
Can you access google?
Cached web pages may still be able to load even without an active network connection. Clear your browsing data and try again.
If you can't access new, uncached web pages, try opening a command prompt and type in, "ping 8.8.8.8". If you get a reply, then you can connect to outbound servers, but may have some issues with your proxy settings, or ports if port forwarding.
8.8.8.8 is google's public DNS server. It is a well-known test connection that assists in troubleshooting.
If your computer shows you are connected, you can see other devices on your home network, but you just can't get to Google? Your issue would lie with your IP routing or WAN connection. Try a speedtest, a ping test to an alternate computer for testing, or reset your home router to factory settings.
If you have admin control over your home router or switch, check the following areas:
- Access Lists
- Routes
- Proxies
- VLANs
- Ports
A summary so far: You have a computer that turns on and works, that computer connects via layer two to get an IP address associated to it, which then gets routed to your WAN connection.
Layer 4 | Transport
The transport layer involves packet reliability and errors during the connection. In everyday life, this would mean that a stream suddenly stops but the page still loads. Or a page takes too long to respond. If there is an error message, Copy/Paste into google and see if there is already a solution
Sometimes you may be trying to access certain sites during peak hours. You try a stream and it takes hours to load, then maybe you shouldn't watch live football on Superbowl Sunday in the suburbs through a VPN while "ehem" legally downloading the complete Game of Thrones in the background.
There are two protocols that might seem familiar, called TCP and UDP. If you have hickups in your stream, that's UDP pushing everything it can at you and you can only catch so much. If you're scrolling through a reddit feed and suddenly posts stopped loading, that is more TCP. TCP cares if you get the right information, it checks up on you, it brings you cookies and asks how the kids are doing. If something seems off, it sends it again until you get it.
To fix layer 4, you have a couple things bogging down your day.
- Bandwidth.
People think that higher bandwidth means you have "godly internet and nothing can ever hold you down!" but this may be misunderstood. While, yes, bandwidth does have an effect on your speed, it is not in and of itself "speed". Bandwidth allows you to have more going on, your speed can still be running at whatever speed it was sent to you. Like the Autobahn, you can have reliable speeds as long as everything is running as it should. If you have two slow people blocking your path, it slows down all the traffic. You make it 8 lanes (adding more bandwidth) you're allowing more ways for the traffic to move, but you're not changing the speed of the vehicles.
Netflix uses, for example, 25 Mbps to stream a video; you have 100 Mbps internet to your home. That means you have 75 Mbps to be able to service all the other devices in your house that need the internet. If you have two people streaming at one time, you might be able to reliably stream for both of you. But if you are also trying to load Facebook, Instagram, or any other image-heavy sites, these use a lot more of the spare room you had before.
2. Distant end
If you have the godly internet of King Nerd the Third, you still could be limited by the servers. If you connect to Germany from Hawaii, that data still has to hop across the ocean just to get you your cat video. Not everything will get to you immediately.
Layer 5 | Session
The Session layer isn't much in need of troubleshooting, as it is more a tool for troubleshooting.
For example, the Session layer is exactly that, the session. The connection made to the distant end is policed by this layer and can track information and maintains a synchronous flow of data. While the Transport layer sends UDP data for videos, the Session layer is making sure the audio and video reach the destination at the right time and in the right order.
Ever had a video stream the visual before the audio? A troubleshooting method to this is to delay the audio track or the video in your playback settings. This isn't as common of a problem anymore with modern hosting, but with older streaming hosts this was almost commonplace. Yes, I know you know what I'm talking about, with anime streams having audio that didn't match the visual, and subtitles completely out of sync... Sad times. But, here are some tips to remedy that!
- Delete SSL state/cache in web browsers and refresh the browser
- Pause, wait a few minutes for a buffer zone, then re-start
- Log out, then back in
- This would refresh running programs and services
- Try reducing lag as much as possible by eliminating other programs in the background or other tabs open
- Try another user account on the same computer. If it works with another user, check user credentials/permissions
Layer 6 -- Presentation
Ǒ͓̖͚͕ͤ̒͑̓̌ͧ̋̀̒̈́ͬ̋͆̚͢͡ͅh̵̢̯̰̦̤̙̞̖̠̰̮̟̗̠̭̃̀͊͛͟͞ ̸ͬ̑̿̓̊̐̔ͤͤ̄̚̚҉̥͚̜̫͓̳̰̫̺̝͓̦̻͉̀̕͜n̵̬͉͈̹̮͕̻͇̠ͩͨ̓̉ͮ̎ͦͯͥ̏ͭ̓̌̔̋͘͢͝o̴̙̭̘̠̥̰͓̱̲ͧͯͭͭͬͨ̇̔̄ͮ̀̀ͅ!̢̠̥͈̩̺̼̟̙̠͚̼ͯ̂̎͟ ̜̩͇̱̰̫̯̥̬̳̥͉͔̹̤̩̻͋̌̉̓̋̓̾̂̒̀͘͢ͅW̧̧͚̖̪̥̻̳͎̤͙͉̟̻̳̞̭͓̲̔̑̇̓̏̾͗̈̌̏̊ͭͭ̓h̨̩̣͍̣̹̞̣͈̜̳̙̣̹̖̬̣̿͛̾̐̌̽̓̊͊̀͘͝a̧͚̗̬̰̰̹̘̟̭̹̣̜͙̬͈͉͆̓̎ͧ̒ͮ̆͝t̵̝̤̣͇̳̹̦̾͑̂̒ͬ͒̕͝ ͋̉̾ͫ̑̄̚͘͏̷̲̦̩͙̖͕̼̬̭̗̝̹̹͘͡h̸̢ͪͯ̔ͥ́͏͇͕̮̹͓̬̞̭͎͇͈̮͍͉̲̟͞a̢͊̏̀́͐ͪ̔ͩ͒͑̋̓҉̵̬̣͙̼͖̫̪͓̼̤ş̷͙̙͙̞̘̰̮̮̯̮͆̋̑͆́̀̚ͅ ̡̛̣̖̰̪̺̥͇̠̞̟̲̠̓͌ͫ̕͠ͅh͇̲̱̲͓̟̜͔̤͎͍̩̪ͦͤ̓͑ͫ͐ͬ̆ͦ̆̆̿̌ͯ̋̐ͭ́͟a̛̩̺͚͓̦͉̝̮̠͔̭̖̝̩̻̼͎͎̎͂ͦ̍͛͌͛̎̃̈́̀͑̈́͒p̝̺̞͕̞ͯ͆ͮ̒̈́ͩ͒̅ͦ͋ͮ̈͆̑̐̅͟p̢̥̯̻̙̬͚̘̥̬̱̺̰̯̞̠̣̗͒̽ͪ̽͌͗̈̍ͮͤ̔̅̈̂̅ͨ͡e͊͆͑̏ͮ̀̃͏̵͕̮͖͇̪̟n̊͊ͫͨ҉̶̬̝͔̺̹̣̙̰̦̭͍̲̻̫̗͝ȩ̻͇͇̗͙̳͖̦̟̭̰͉͔̼̣͓̻̱̀̇̏ͥ̚͜d̛̗̙̥ͧͥ̊̃͆̔ͫͤ͞ͅ ̛̛̥̻͈͉̜̃̆̈́ͯ̓͋͗͐ͯ̽̽̈́͢͝ḥ̙̥͔͕̲̬̲̯̫̘̦̹̼ͦ͒̃̍̎͑̍̐͐͛̈̔͛̽͋ͬͫ̄́̚͘͘e̛͕̖̳̤̮̲͚̦̪̹̘̝̮̦̙͙̣̐̓̋̽ͦͫ̅ͩ̒̑ͪ̌́r̨̛ͧ͌͋̃̓̄͂͗͑̋̈ͩ͊̉ͬͨ̂̈̉͏̮͎̰̤͚e̡̪̼̼̥̟̭̼͓̯̩̪̝͔̙͆̀͂ͩ͒͗ͫ̂̔ͧ̇ͩ̍̔̋͝ͅͅ?̴̰͖̞͎̥̼̯͕͔̽̉̃ͬ͑̉́̃͌͗ͩ́͟!̶̩̬̣̫̖̘̺͖͐͊̎ͥͩͣ̕ͅ?̷͚͚̦̲̤̹͓̩̱̥̲͈͂̽͑̎ͯ̓̕͢ͅ!̀ͦ̂̾̾̏͋ͧ̊̊̄ͤ́͌͑ͯ̀҉̶̞̭̯͇̬̙͓̬̬̣̠̰̠͉̭̙̺̦ͅ ̲̣̙̯̖̝͇̙̬̺͇̗͋̄ͮ̏̎ͫ̅̂ͫͧ͋ͦ̌͑̉͗̀́̀̚͘
̷͈̹̺͙̙̻̹̬̖ͦ̍̍ͣͣ̌ͥ̍̂̈́͒̂̏
̴̧̙͍̣͕̭̻͕́͌̋ͤͦY̸̛̼̝̯̼͎̗͉̝͖ͣ̾̂̌́͂͐͋̅̄́̿͛͊̔͒̀̕͜e̎̐́̌ͨ̅̃ͣ̐̌ͧ̀҉̗̬͎͈͙̟́̀͡ă̷̷͕͇̱͇̱̩͈̘̜͖͚̦͓͈̗ͥ̐͛͒ͦͧ̽ͧ̑̎ͫ̏͗̈́ͤ͜͡h̶̸̛͎̜̻̟̪̤͎̙̲͙̝̝̘̹̦̭̟̱̰̋̃̆̏̓́͞ ̧̈́ͬ̏́ͩ̇͌̈͆̚͏̷͠҉͖͈͓̮̳͍̣̮͎̰͓̻̰̫̞y̶̗̦̼̪̮͙̼̣ͤ̈ͤ̇̔̎̒̅̎̆̊͑̇ͬ̈́̚oͫͭ͐ͤ͆͂̆̾̌̈͛̀̀͋̇ͬ͋̂͏̛҉̙͖̥̖̹̠̜̘͓̗̼̘͎̠̝u̧̡̡̳̟͈̻̭͈̩̿̇ͮͫ̀͢ ̸͕̟͙͌̏̊ͥ̾̇̽ͥͩ͒̊̾̅̕͝j̤͕̰͉̖̥͕̣̯̩̄ͬ͆ͭ̀ͅͅư̢̓ͭ̎ͮ̾ͥ̔ͩ͝͏͔̥̝̦͇̦͓͚̼̖̬̩͉͚̜͢s̨̧͕̫̹̤̜͚͙̲̐̿ͨͩ͑̆̓͗̅͐ͯ̐̓̑̅̕͜͞ṱ̨̳͍̫̠̹̫͈̐̌ͦ̓ͣ̍̃ͣ̈͗ͮ̀̕͢͡͝ ̴̷̇̋͐̚̕͏̨͇̳̟͇͕̞̭̫̗̤m̡̳̥͈̣̝̘̜̰̣ͬ͊̒̓ͫͨ̿̈́͋͌̐̾̐ͧ͊͒ͬ́́ę̛̺̞̞̤͇̼͎͍̬͇̰̆̓̈͂͊̿̃͑̉s̸͍̗̭̟̖͉̘ͩͭ͂̔ͣ́̎ͩ͆͐ͫ͑̀s͔͈̺̠̹̮̥̝̙̘̩̭͇̱̖̱̟͉̞ͦ̏ͣ̍͂ͨ̔́ͣ̋̅͛̽͑́͜e̵̛̜̳̥̣͈̭̝̥̠̖̙͗͛ͤ͂̇͐̀͠d̵̵̡̤̫͇͖̺̤̤͙͒̉̀ͥ̓ͯ̊ͣ̒ͪ͛ͦ̚ ͖̪͈̝̦̟͈̊ͥ̃̀̕ͅũ̑ͦͯ̂͗̓ͦ͊̿̚̚͢҉̢̨͚͎͈̟͍̯̝̰̝̪̲̯̭̺̘̼͠p̴̷̛̤͎̙̰̘͓̹̤͓̫̍ͦͮ̀͋̔̐̕͠ͅ ̷̺̱̞͇̬̲̝̲̯͖͖͈̺͕̟ͫ̀ͤ̂̅ͨͫͣ̌̂̀̆́̿̿ͤ͗͐͝ͅL̴̩͎̠̯͚̗͚̝͓̫͉̜͓̏ͧ̂ͤ͛̅̅̎́̀̕͢a̷̴̜͔̼͔̹̻̦ͥ͒̑̋̐͐̃͒͋͛ͤ̑͗̓ͯͮͥͥ̕͞͝y̶͎̩͍͖͇̠̗̠̙͕͐ͨ̇͂͂͛̍͌͗́̋̀͑͡ͅe̶̷̸̦̮̬̮̬̯͉̫͎̱̪̙̘̮̖͓̮͎ͭ͛ͥͭͪ̊͆̇̉̈́ͨͦr̨ͩ̆ͫ͒ͬ̋̌͋̏͛̊̈ͩ̒҉̴̯͉̯͉̬̯̻̦̮̬̰̟̯̹͖͎̪͓͘͠ͅ ͇͇̟̬͎̑̏̾͂̈ͪ̓ͫͩ̀͘͞6̬̠͖̭̋ͭ̋̉͐͛̌̿̓͒ͦ̈ͯͨ̌͒͂̀͘͢.͌͌͐́̀ͣͯ́͐ͦ͗͌ͯͬ͏̧̢̳̼͉͉̯̰͙͍̀͠ͅ
̛̭͕̝͔̪̲͓̟͖͈̟̼̣͍ͬ͐̓ͩͧ̀͞
̶̞̤͎̘͎͕̣̰̺͚̗̦̻͕͗̏̆ͤ̄̿ͥͫ̍̈͗ͤ̚͠B̴̄̒̄͐͢͏̵̢͍̼̝̱̻̮̣̝̦̦͇̼̜̻̟̠̲̝̘u̷ͣ̉̍̇̏ͬ͊͏̧͉͎̝͚͚̱͙̹͙̘̳̬͕̞̣͝t̢ͩ̌ͭ͗̔̒ͮͤ͑̓̿ͩ̔̄́͏͚̗͎̖̗͍͍͖̘͚̤ͅ ͊̈̅ͦ͆͏̸̷̞̱̬͈̮͙̳͖̫̘̣͇͎͎͟ͅh̿̿̓̄ͭͮ͒̃ͤ̾ͣ̆̔̏͏̷͕͓̗̬̞͕͔̲͓͕̫̙͘ͅͅő͈̥͍̭̩̠͕̗̪̝͙̈́ͪ͐ͦ̎͑ͪ͂ͥ͗̊͘͝w̸̷̸̡̥͎͇̥͈̪͇̖͉͓̘̜̬͔̱͉̼̟͌ͥ͗͒͂̑ͫ̏̋̂̂ͣ̉͞ ͩͬ͑̊̎͌̒̏͊̋̇ͥͫͩ͏̱̺̭͚̳͍͖͖̱̹͎̭̻̗̫͇̝̼i̵̵͎̲̮͓̟͖̥͕̙͖̼ͥͤ̿͆ş̸̧̙͖͍̘̰̜̦̹̹̬̦̭͍͎̰̣͍̐̿̃̄̑̂͌͗͑̎̀͡ͅ ̴̢̟̮͍̭͉͈̩̲͙̻̟̙̻̋̾̐́ͮ̀͌̋͌ͪ̏͑͗̍ͫͫ̆̚̚ͅẗ̵̡͈͕͚̥̺̪͓̝̞͖̗͙̲͉́̽ͣ͛̽͐̅̅͛̄̄̚̚ͅh̡ͩ͂̂̀̔ͧ̇̑ͬ̊ͩ̈̏̇̚҉̝͓̮̺̱̯͕̫̘̜͈̹̤͔̣͍ͅͅi̶̵̵ͬ͌̂͛ͬ̄̈́̇̐ͯ́̇̓̉̊̇҉͈̳͎̣͇̠̩͍͞s̶̛͇͔̫̞̤̮̼̣̣̯͕̑ͥ̄̾ͪ̑̄̎ͮ̿͛̀̚͜͢ ̵͓̠̘̞̥̱̣̼̯͖̟̗̺̜̰̘̩̻̔ͫ̒̾̏̿͆̽̈́̓͗̇̒͂̀͡fͯ̓̆͠͏̵̤̥͎̫͙͈͞ͅi̸̸͈͕̥͍̮̹̖̺̥̤̮̙͙͙͔̩͑̌̈́͋̆̂͟͟ẋ̵̢̡͓͎̮̦̝̟̫̻̰̗̩͍̰͙͌̆͘e̶̷̡̛̻̲̺̹͔̟̫͔̮̤̮̗͈̻̦͍̝̜ͧ̌͒͛ͣ̃͒̀͌̈̔̉ͫ̄̚͡d̴̠̰͉̫̻͚̤ͮ̔͐̓̅͌̏̄̌ͭͫͭ̈͜?̸̷̺̺̘̗̩̘̹̱̉̊ͣͣ͛̀̄ͧ͑̈́̃̃̔ͧ̄̐͑ͬ͝ͅ
̷̴̨̡̹̭̰̖̙͉̖̥͑ͧ̽̏ͣ͆ͥͮ͒͂̓̈̐̌ͪ̿ͧ̚̚͘
̶̶̟̥̺͙͙̳̬̓͋̆̋̀ͨN̵̸̩̭̬̼̮̼͈͍̩̬̬͛͛͑̂ͣ͒ͫ̌͌͌̌ͫ͌ͭ̌̚͢͝ö̧̡̐̓̏̑̾̿̽ͧ̋̑͜͞҉̝̞̗̙͕͈̯̥̩̜͉͍ ̵̧̪͍̱̜̜̈́̾ͩ̉̒̉̀̋͌͆̈́̂̇̄̈́̊̍ͯ̆͘͠i̶̧͇̩̩̱̥͎͕͉̰̝̤̲̻ͭ̆̿̏̀̅ͬ̍ͪd̛̫̳͔̱̞̖̘̖̮̗́ͮ̅̉ͩ̓ͯ̃̇ͮ̉̒̏ͫ̔͊̄̊̀͘͝e̞̠̦͔͈̖̻̥͎̗͚͕̔ͤ͊ͮ̍̍̋ͬ̂̌̄̔ͤ̐̔̊̀͘͡͠ȁ̸̶̢̟̗̙͚̠̻͈̘̟̙̳͔̳̞̎͌͗̊̍̇̊̋ͣ̑̓̅͊ͯ̅͠ͅ.̧̓̆͋͂̎̊ͥ̄͝͏̷̧̹̣̖̖̝̤̤̰̭ ̔̊̐̈́̈́͐͢͏̗̟̥̰̣͙͈̲͓͈̪̘̦̩͍̥̞͖ͅR̋̑ͦ̾ͩ̄ͩ̚͠҉̵̨̬̠̙̝̞̩̹̫ȩ̧͓̜̳̥̬͇̣͚͈͍̪̹͎̼ͤ̍̌̈́̂ͮ̀͢͡f̢̥̤̹̞̝̟͔̺͙̼̫͍̰̜̠̼̯̎̋̿̈ͥ͒ͧͨ̿̽͌̓ͭ͂ͥ͆͒̚̚̕r̛͓̦̣̦͈͔̟̠̩̙͈̗̳̃ͯ̌̔ͣ̆ͦ͞e̵̩̙̻͉͈̫̟̻̘̞͈͈̣͈̞̝̠̱ͯ́̈͊͛ͬ̈̚͢s̸̢̬̖͎̮̦͎̼͙̰͇͇͍̰͇̟̯͙̓͐͋͒̑̈͗̉͋͊͗ͣ̉̏ͥ̊̏̂ͅh̾̋̒̊̒ͮ̄͋͐̃̑̒̃҉̴̭̞̯̗͖̤̩͈̳̳̩̠͓̹̘ ̧̛̤̟͔̲̳͚̤̪̻̻̝̮̯͖̝̥͕͕͕ͫ̂̋ͯ̔̆͂̿̆ͭ̌͒̂̚͜͝t̯̳͓͓̳ͯ̏͆̔̋ͮ̈́̍͆̍̌͌ͤ̑̐̓ͤ̈́ͬ̀̕̕͞h̷̤̫͎͎͔̳ͤ̈́͂ͦ̽̓ͭ́̽̋̒ͪ͂̌ͦ̋͘ẹ̜̤͍ͣͣ̄ͪ̍͐ͯͯͣ̍ͤͤ̚͟͠ ̶̡̨ͬ̀ͦͫͪ̎ͩ̈ͬ̒ͨͦͥ̾ͥ͂͒̿́҉̥͖̳͎̝̪̯̹͚̺p̴̨̠͇̬̤̻̻̮̫̱͖͈̥̦̓ͪ̃ͥ͊ͤ̄ͫ͗̂ͥͧͣ̎͢͞ą̡͇̻̠̰̱̦̝͕̬̖̘̬͕͈̦̜͈̥́ͩ̈ͪ̒̏̐̓ͦ͐͋̉ͧ͆́́ͅg̨͇̯͓̺͖̤͚̯̪͙͚̓ͭ̆ͩͩͯ̀e̶̢͙̹̯̠͈̗̘͙͖̼̲͕͚̥̺̙̱̤̱̍͑͌̄ͫ̄͗ͭ̆̕͢ ̨̧̛̥͇͔̝̦̗̟̪̣̜̗̘̿͆͛͒ͦͣͦ̈͋̂͊ͭ͠ͅͅo̡̼̖̙̹̲̪͔̻̞͎ͧͪͯ̇̐̈ͥ͗̋̌͘ͅr̴͈͎̠̯̦̔͆͂̍ͬ͡ ̛͔̺̼̹̝̖̘̪̘͔̠̤͉̲̜̿̾̍̏̋ͫͮ̋͒͢ͅg̡͋ͯ̇ͧ̐ͭ̍ͬͤ̌̂ͯ̑͋̆ͥ̌̄̎͏̴͍̜̠͓̤̯̪̻͓̬͔̥͓̫̙͖̺i̜̺̰̭͉̬̖̲̞̩̺̫̼̜͓̊͒͆̇͊̈́̃͠v̴̢́ͨ̈́ͦͥ͆̈́̌̍̃̐҉̥͙̭̯̣͚͔͕e̸̦̦͙̞̤̪̩̘̜̠̪͓̟̖͓͇̲͑̋̆̽̀ͦͬ̿ͤͧ̾́̕͟ ̴̨̙̲̫͚̪͆͊̎̌̈́ͥͣ͌̇͌ͯͣͬ̉ͮ̈ͭ̐̀͟u͑̌̓̏ͬ͆ͣ̐̿̅ͤͭͤͨ̑̾̈́҉̤̺̥͖̞̝̳͙͍̣̫̗͘͢͞p̧̛̞̲̬̳̊ͤͦ̉̌̽͡͠.̶̶̶͙̥̱̱̣̭̩̜̫͈̬͂̐̽ͭͬ͑̇̈́ͦ͒̈́ͨ͜͜
You can't really fix this, as this is generally just a refresh the page or try a different font. The distinction between the 6th and 7th layer is very broad as well, so think that the computer's translator has gone bad as the data was reaching the 7th layer (or application). This translator was trying to read Greek but spoke German, and the computer was trying to produce English. Things just get a little messy.
The best example is when you see apostrophes turn into a bunch of characters that don&%t really belong? This usually happens when an Apple iOS tries to use certain protocols that a Windows OS doesn't translate the same way. And winds up looking different on other computers.
Another way you may have heard of this is encryption. This happens on Layer 6. So if something comes across as a bunch of gobbledygook, that message most likely wasn't meant for your eyes.
Most issues with this occur on cross-platform applications. With newer standards coming out day by day, this isn't as common as it was a decade ago, but to get rid of it you may have to run some programs in compatibility mode, or use a different file format when saving and sharing a file or photo.
Layer 7 -- Application
This layer is used as a means of communication between the operating system, the application, and the end-user.
- Check for drivers
- Try a system restore
- Check Task Manager
- See if the software has conflicting software
- Try the Reliability Monitor
- Type "Reliability" into the start menu, and it will give error reports
- Re-install the software.
Summary
If all else fails, try a fresh install of the Operating System (OS).
Back up files to another hard drive and give the current hard drive a nice clean wipe. Install software one-by-one and see what program causes the conflict. Check error codes, as they were most likely placed there by the manufacturers, and try the specific fix actions for those errors.