Various types of multimedia applications take up a significant part of modern communication networks. Among these applications, we have telephony, video conferencing, surveillance systems, distance-learning systems, and many more.

In multimedia applications, the requirements from the network are different from the requirements in other enterprise applications. While applications such as HTTP, e-mail, and file sharing require high bandwidth, a telephone call, for example, requires less than 100 Kbps, but is sensitive to delays, and very sensitive to jitter (delay variations). While most applications require high downstream to clients in remote offices, surveillance systems require the upstream direction as they are watched from monitors in the HQ, so the monitors actually download the video from the remote site.

In this chapter, we will focus on these voice, video, and multimedia applications, how they behave over network connections, and how to use Wireshark to troubleshoot problems when they don't work properly.

In this chapter, we will focus on Session Initiation Protocol (SIP), Real Time Protocol / Real-time Transport Control Protocol (RTP/RTCP), Real Time Streaming Protocol (RTSP), and other common multimedia protocols.

We will start this chapter by presenting the available tools that Wireshark provides us for troubleshooting voice and multimedia sessions. We will focus on how to resolve SIP problems and how to troubleshoot RTP/RTCP sessions, then we will learn how to troubleshoot video systems, including video conferencing and surveillance systems.