SIP Transactions

In SIP, transaction is a fundamental concept that represents a complete cycle of a request sent by a client to a server and all responses to that request sent back. This cycle is essential for the reliability and management of SIP message exchanges. Understanding transactions is crucial for working with SIP, as they are a central component of user agents and can significantly affect the behavior of stateful proxies. Let's understand the Transaction interface and its key methods in simpler terms.

Transaction Interface

What Is a Transaction? You send a letter with a return receipt request. You drop the letter (request) in the mailbox (client transaction), it travels to the recipient (server transaction), and you get a notification (response) when the recipient gets it. In SIP, this whole process—from sending the request to receiving a response—is what we call a transaction.