UDP

Characteristics of UDP Packet Loss
Research paper explores the effect of TCP traffic on UDP.
http://www.isoc.org/isoc/whatis/conferences/inet/97/proceedings/F3/F3_1.HTM

Connectionless Transport: UDP
Describes its structure, properties and uses.
http://www-net.cs.umass.edu/kurose/transport/UDP.html

RFC 768 - User Datagram Protocol
Provides an introduction to the protocol, its formatting, and interfaces.
http://tools.ietf.org/html/rfc768

User Datagram Protocol
Graphically presents the structure of the packets, and explains the different fields.
http://www.networksorcery.com/enp/protocol/udp.htm