mmdump - A tool for monitoring multimedia usage on the Internet

— The Internet is being increasingly used to support streaming media applications and real-time voice telephony. Audio and video traffic differs from that generated by traditional TCP applications, and, as its use grows, may begin to have a significant impact on network performance. This motivates the need to measure multimedia traffic growth and characteristics. Multimedia applications typically use dynamically assigned UDP ports for exchanging media data. These ports are negotiated using a control protocol such as the Real Time Streaming Protocol (RTSP). To allow measurement of mul-timedia traffic, we have developed a utility called mmdump which uses parsers for RTSP and other control protocols to determine UDP ports and other application-specific information. mmdump extends the popular tcpdump utility to monitor traffic on a dynamic set of UDP port numbers, extracted from TCP-based control protocol messages. This paper presents the design and implementation of the mmdump utility and demonstrates its use in monitoring RTSP-related traffic on the AT&T WorldNet IP network.