Linux Socket Programming by Example

Chapter 14. Out-of-Band Data

This chapter will bring you into the fray of using out-of-band data with TCP. You will learn why it is provided and about some of its pitfalls. Most important of all however, you will become equipped to properly apply out-of-band modes of communication, with any protocol that supports it.

Here is a summary of what will be covered in this chapter:

• Define what out-of-band data is.

• Why is it needed?

• What are the socket related issues of using it?

• What are the variations in the TCP/IP implementation?

• How do you use it with TCP stream sockets?

Defining Out-of-Band

Imagine a lineup of people at the bank waiting to cash their paychecks. The line forms a queue, in which people eventually move forward to be served by a teller. Now ...