This plugin adds UDP protocol support to JMeter. With this plugin you can load test DNS, NTP, TFTP, Boot servers and many-many other systems.
Since UDP may be used both in one-way and two-way communications, there is option to wait for response and corresponding timeout setting.
"Close UDP Socket" - the flag to close socket after processing request. Otherwise, the socket will stay open for the next iteration.
"Bind Local Address/Port" - the options to manually choose which local IP and port should be used to send the request.
Most of UDP applications use binary packet data, which cannot be directly specified in JMeter GUI. UDP Request use encode/decode classe (like TCP Sampler do) to convert request data from GUI into UDP packet data and response data back from binary to GUI-visible text data.
There is embedded encode/decode classes:
Anyone can write his own encoder/decoder, implementing kg.apc.jmeter.samplers.UDPTrafficDecoder interface.
Read Buffer Length
UDP Request reads response using buffer with default length of 4KB. You may override this value by setting JMeter property kg.apc.jmeter.samplers.ReceiveBufferSize in bytes.