In this chapter, we introduced the concepts of network models while covering the OSI model. We discussed how the seven layers were split into upper and lower layers and covered each of the layers by highlighting the function of each layer and their key attributes. We highlighted the process of encapsulation and deencapsulation as data was passed from one layer to the next.
We included a number of areas that an engineer can utilize in the troubleshooting processes. These included the three-way handshake that's used by TCP. Using this knowledge in conjunction with a tool such as Wireshark will allow you to check to see if a connection is being made to the recipient device. We also covered logical network ports and discussed the common ports. Learning about the allocated ports numbers will allow you to ensure you are making the correct adjustments to firewall rules....
