October 2012
Intermediate to advanced
408 pages
7h 35m
English
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Chapter 14
Using Datagrams (UDP)
WHAT’S IN THIS CHAPTER?
- When and why to use UDP
- Receiving UDP messages
- Sending UDP messages
- Multicasting UDP messages
- Understanding UDP limitations
TCP is connection-oriented protocol that provides a reliable, ordered stream of bytes from one network node to another. User Datagram Protocol (UDP), however, is a connection-less protocol that does not provide the delivery characteristics of TCP. When sending UDP packets, you are not guaranteed of the order they arrive in or even whether they arrive at all.
Despite these limitations, UDP can be quite useful; for instance, when you need to broadcast messages, you don’t need hard delivery guarantees or message ordering, or when you don’t know the addresses of your peers.
UNDERSTANDING UDP
UDP is a transport layer, much like TCP, that sits on top of IP. It allows you to send messages (in this case referred to as datagrams) to other hosts without requiring prior communications to set up the required transmission channels or data paths. Unlike TCP, UDP is not connection-oriented and does not provide any semantics for reliability, message ordering, or even data integrity. UDP provides an unreliable service, and datagrams can arrive out of order, appear duplicated, or even go missing without notice. UDP assumes that error checking either is not necessary or is performed at the application layer.
UNDERSTANDING THE USES OF UDP
Time-sensitive applications often use UDP because dropping packets is preferable ...
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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.