The OSI Model Layers from Physical to Application https://www.lifewire.com/layers-of-the-osi-model-illustrated-818017
Common Questions and Answers on the OSI Network Model https://www.lifewire.com/the-osi-network-model-818016
Begin a Career in Desktop Support: IT Certification | Microsoft Learning https://www.microsoft.com/en-us/learning/mta-it-infrastructure-certification.aspx