Datagram : Java Glossary

by Roedy Green ©1996-2009 Canadian Mind Products
index page for letter ⇒ punctuation 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z (all)

Datagram

If your business can be conducted with one small packet in and one small packet out, you can save the overhead of setting up a TCP/IP stream, and use the simpler UDP protocol. The packets it sends are called datagrams. The catch is, there is no guarantee of delivery. You use the Java classes DatagramPacket and DatagramSocket. SNTP (Simple Network Time Protocol) uses datagrams. You send a request datagram to an atomic time server and it sends you back a datagram with the current precise time.

Datagram protocols are great for peer to peer as well. That way a server just makes introductions and the clients talk directly to each other, allowing it to serve a huge base. Great for chat. That is how BitTorrent efficiently downloads massive files with little server overhead.

Ir nio, you can use DatagramChannels.

Learning More

Sun’s Javadoc on the Datagram class : available:

on the web at java.sun.com
in the current JDK 1.6.0_11 or in the old JDK 1.5.0_17 on your local Windows J: drive.

Sun’s Javadoc on the DatagramSocket class : available:

on the web at java.sun.com
in the current JDK 1.6.0_11 or in the old JDK 1.5.0_17 on your local Windows J: drive.

Sun’s Javadoc on the DatagramChannel class : available:

on the web at java.sun.com
in the current JDK 1.6.0_11 or in the old JDK 1.5.0_17 on your local Windows J: drive.

BitTorrent
chat
ICMP
IP
Neworking Properties
socket
TCP/IP
UDP

	Please email your feedback for publication, errors, omissions, broken/redirected link reports and suggestions to improve this page to Roedy Green :
	Canadian Mind Products
	mindprod.com IP:[65.110.21.43]
	Your face IP:[38.103.63.62]	The information on this page is for non-military use only.
	You are visitor number 9,623.	Military use includes use by defence contractors.
	You can get a fresh copy of this page from:	or possibly from your local J: drive (Java virtual drive/mindprod.com website mirror)
	http://mindprod.com/jgloss/datagram.html	J:\mindprod\jgloss\datagram.html