title: What is the difference between the normal INVITE and the INVITE on hold in a session using SIP protocol?
body: <p>hi all am new to software field and stack overflow too. I am analyzed the back end flow of a session between the caller and the callee using SIP protocol. I am little bit confusing on the normal INVITE and INVITE on hold. can anyone explain the difference between them?<br>
  Thanks in advance.</p>