Chapter Summary

Almost all application layer protocols have a common set of functions that need to be performed. Rather than have each application protocol implement those functions, the creators of networking models put several of these common functions into the layer below the application layer. In TCP/IP, that layer is the transport layer. In this chapter, you read about the most popular option for TCP/IP transport layer protocols: TCP.

TCP provides several features for applications, including

• Basic delivery through encapsulation

• Breaking large chunks of data into manageable sizes using segmentation

• Ensuring delivery through error recovery

• Getting the data to the right individual program, not just the right computer, by using port numbers

• Simplifying the creation of applications by hiding the details of actual data delivery from the application