July 2002
Intermediate to advanced
528 pages
15h 13m
English
Content preview from Practical VoIP Using VOCALBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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High-Level Flow
The two major functional blocks in the base code are the SIP and Worker threads.
SIP Thread
The SIP thread is a conceptual bundling of the threads that run the SIP stack. As we’ve seen in Chapter 8, there are actually several threads in the SIP stack, but it is easier to understand how the base code works with the SIP stack if you think of all the SIP threads as one complex thread that sends and receives SIP messages to and from the network. SIP messages are received by the SIP thread from its stack’s message queue and placed in its output First In First Out (FIFO) queue. See Chapter 8 for more information about FIFOs.
Worker Thread
The Worker thread is the application thread that takes messages from the FIFO and processes them using the builder, feature, state, and operator structures. Each class in the structure is a class container for the class below it. The content is filled according to the designer’s requirements. For example, the Marshal server (Chapter 11) has one builder, one feature, and one state but multiple operators for each message type, whereas the UA (Chapter 10) has multiple operators and multiple states. In the event that the Worker thread needs to send a response or forward a request, it makes a call to asynchronously send the message. The SIP thread then sends the message over the network.
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.