CS736 PROJECT REPORTAnurag Gupta1. INTRODUCTION2. PROTOCOL STUDYA new set of protocols have recently been proposed to support the timely delivery of Real Time Streaming Multimedia. The three major protocols that we studied include the Real Time Streaming Protocol (RTSP), Real Time Protocol (RTP), and Real Time Control Protocol (RTCP).RTSP is an application-level multimedia presentation protocol for control over the delivery of data with real-time properties. RTSP provides an extensible framework to enable controlled, on-demand delivery of real-time data, such as audio and video, using the Transmission Control Protocol (TCP) or the User Data Protocol (UDP). All known RTSP servers to date are TCP-based, though the specification has provisions for a UDP-based version.The Real Time Streaming Protocol (RTSP) (RFC 2326) is an Internet Engineering Task Force (IETF) Proposed Standard for the control of streaming media on the Internet. It was jointly submitted to the IETF in October 1996 by RealNetworks and Netscape Communications Corp. and was published as an IETF Proposed Standard in April 1998.2.1.1 RTSP METHODS2.3 Real Time Control Protocol (RTCP)3. PROXYA proxy server is a server that acts as an intermediary between an end user and the Internet. The end user is typically part of an enterprise. By directing all traffic from the end user to the Internet through the proxy, the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and part of a firewall server that protects the enterprise network from outside intrusion.A proxy server receives a request for an Internet service from a user. If it passes filtering requirements, the proxy server looks in its cache to see if it can service the request. If it finds the requested resource in its cache, it returns it to the user without needing to forward the request to the Internet. If the resource is not in the cache, the proxy server, acting as a client on behalf of the user, requests the resource from the server out on the Internet. When the resource is returned, the proxy server relates it to the original request and forwards it on to the user. An advantage of a proxy server is that its cache can serve all users. If one or more Internet sites are frequently requested, these are likely to be in the proxy's cache, which will improve user response time.Client has no knowledge of Proxy4. RTSP REFERENCE IMPLEMENTATIONRTSP HandshakingDATA TRANSMISSION6. RESULTS7. FUTURE WORKCACHING OF STREAMINGMULTIMEDIA ON THE INTERNETCS736 PROJECT REPORTAnurag GuptaKiran Chitluri{anurag, kiran}@cs.wisc.eduComputer Sciences DepartmentUniversity of Wisconsin, MadisonMadison, WI – 53706December 21, 1998ABSTRACTReal Time Streaming Multimedia is growing at an increasing rate on the Internet. Caching themultimedia files as they are routed through company firewalls and proxies is the ideal way to incurbig savings on Internet traffic and enable high-speed delivery of media content to the end user.Currently Inktomi Corporation has developed the only commercial implementation of a StreamingMultimedia Caching Proxy. By studying the Real Time Streaming Protocol (RTSP) used for controlof real time continuous media and the Real Time Protocol (RTP) used for media data delivery andusing a Reference Implementation of a player and server supporting streaming media, we havedeveloped a free academic implementation of a Proxy capable of caching streaming media, for theresearch community.21. INTRODUCTION Multimedia on the Internet is growing at a dramatic rate with the number of media URL’s tripling over thelast nine months. Bandwidth improvements in the near future will only aid in making multimedia more popular onthe Internet. Today, Streaming Media is the most popular way to transmit multimedia over the Internet because itallows the user to experience the media as it is being received instead of forcing the user to wait for the entire file tobe downloaded before it can start playing it. Since these media files change rarely, they lend themselves well tocaching. By servicing requests for multimedia files from cached copies at Proxies, organizations can save big onexpensive Internet Traffic. In addition, high-speed delivery of the media content is possible since the media files arebeing brought closer to the end user. RealNetwork Inc. is one of the largest companies that support streaming continuous multimedia. MostStreaming Media Servers today are ones provided by RealSystems and over 85% of streaming media on the Internetare in Real formats [1]. Streaming multimedia has only recently been publicly available. In April 1995 Real Audiointroduced Streaming Audio and shortly after in August 1995 Streamworks introduced Internet streaming video.Currently, Inktomi Corporation’s Traffic Server is the only commercial implementation of a multimedia cachingproxy. We describe the protocol specifications for Streaming Multimedia essential in the design andimplementation of an intermediate proxy capable of caching multimedia files. We also discuss the implementation ofour application level proxy designed to interact with a reference implementation of the Real Time StreamingProtocol (RTSP) client and server downloaded from the RealNetworks Web site. This report is organized as follows. In Section 2, we explain the protocols used for the transmission ofstreaming multimedia. Section 3 discusses the different types of proxies. In Section 4, we discuss the details of thereference implementation of the client and server and how they exchange control messages and data. In Section 5,we describe the implementation of our application level proxy and our caching method. We also discuss the changeswe made to the reference implementation of the client. Section 6 presents the results and in Section 7, we discusspossible future work.2. PROTOCOL STUDYA new set of protocols have recently been proposed to support the timely delivery of Real Time StreamingMultimedia. The three major protocols that we studied include the Real Time Streaming Protocol (RTSP), Real TimeProtocol (RTP), and Real Time Control Protocol (RTCP). RTSP is an application-level multimedia presentation protocol for control over the delivery of data withreal-time properties. RTSP provides an extensible framework to enable