As you have seen in this chapter, there are many issues to consider in moving a packet from one place to another. This is why TCP and IP are tied so closely together. They both perform critical jobs that make the Internet work as well as it does. You learned that TCP/IP works in layers, and that each layer performs a particular job. If any link in the chain fails, the whole thing collapses. Fortunately, this doesn't happen very often.
Reliability is a very good reason for making TCP/IP available on all operating systems, in one form or another.
TCP/IP, though, is scalable and mobile. If there's a situation where TCP/IP can be leveraged, then you probably won't be surprised to find that connectivity already exists. Remember to always take into account all the active protocols that your internetwork already uses and make sure that a transition to TCP/IP will not cause irreparable harm to user access. Other than that, it's a piece of cake.