Protocol and Network Management

Alicia Dease

Written Summary of Chapter Seven "Multimedia Networking" from the text

"Computer Networking: A Top-Down Approach"

The internet is becoming a place which increasingly meets the all the electronic needs of its users. With the advent of multimedia content and the ability of people, even in remote areas, to have access to broadband capabilities, any function of a telephone, television, or other single-use multimedia device is becoming intertwined with a computer's new multimedia ability. Chapter seven in the text defines and discusses the technologies that are, and are becoming, available to the public. This summary will include what these multimedia services are, a simple synopsis of how they work, and, finally, the future of the many applications that providers continue to implement.

The text broke the advances into three simple groupings -- streaming stored audio and video, one-to-many real-time audio and video, and real-time interactive audio and video (Krouse and Ross 598) -- which encompass all phases of the technology currently in use. Streaming stored audio and video can be further broken down into three component parts: stored media, which is prerecorded and stored on a dedicated server; streaming, audio or video that continues to load as the customer is watching it; continuous playout, which requires that the media be received instantly by the consumer or "users experience frustrating buffering delays" (600). Streaming live audio and video is an application that can be used like the more traditional television video signal. This drawback is that it cannot be fast forwarded, like stored media, but it can usually be paused and reversed. There is also generally a delay between when the user logs on to the feed and when they actually begin receiving the streamed content (601). The third category, real-time interactive audio and video, is "often referred to as internet telephony" (601), and it is becoming a much more critical aspect of broadband internet use. So far, this form of media has not been able to catch up to the use of a telephone for voice or picture quality because of "packet jitter" (602), but suppliers are looking into ways to make this technology more user friendly with better quality.

This media can be complicated, which is illustrated by the sometimes questionable quality, but researchers are beginning to make inroads into a product that can mimic the real time aspects of traditional television and telephone technology. As any media type improves, so does the quality of reception within the type. Voice recording began on a tin tube with notches, holes or groves cut into it. Now, people can enjoy a voice experience that resembles a live performance. Streaming stored audio video can be used either with a regular server or "special streaming servers" (608). One of the ways that this multimedia function has recently been enhanced is via a real-time streaming protocol (RTSP) (613). This protocol allows the user to control playback (613). However, all services are subject to what type of network service they are connected to. For example, a best-effort service does exactly what the name says. It will try to keep the video streaming, but there can be no guarantees because of the variable involved such as packet loss, end-to-end delay, and packet jitter (619). For the third type of application to be used, (real-time interactive) the challenge going forward is that standards need to be established (631). These protocols (RTP), are complicated in design, in that they require several steps to actually deliver the media, but they increase the speed and quality of the media received (633).

Service is the key to this type of media. Customers have become accustomed to the sound and video they are able to receive from traditional devices, so any new innovations need to increase this expectation to survive the market (647). Possibly the best case scenario is to provide "classes of service" (647) that will allow customers to select how well the media they receive performs. Many people have already done this when they choose the type of internet they receive. From dial-up to advanced broadband solutions, customers can already decide how well the media will perform. The text offers a variety of scenarios, using different levels of connection, which could enhance the service to the user (652). But even with those different levels of media service there is still a need to determine "scheduling and policing" mechanisms that will allow users to realize the benefits of the media (653). Unfortunately, even with the best technology in the world and an optimum connection there is no guarantee that the signal will continue at an optimum level (665). Thus, the industry still needs to determine methods of guarantee, such as resource reservations [HIDDEN] and QoS (669), that can get the product to the customer without interruptions or delays. The forward-thinking designs of service network protocols could make sub-standard delivery of the media a ghost of the past (673).