Handbook of Local Area Networks, 1998 Edition:LAN Basics Click Here! Search the site:   ITLibrary ITKnowledge EXPERT SEARCH Programming Languages Databases Security Web Services Network Services Middleware Components Operating Systems User Interfaces Groupware & Collaboration Content Management Productivity Applications Hardware Fun & Games EarthWeb sites Crossnodes Datamation Developer.com DICE EarthWeb.com EarthWeb Direct ERP Hub Gamelan GoCertify.com HTMLGoodies Intranet Journal IT Knowledge IT Library JavaGoodies JARS JavaScripts.com open source IT RoadCoders Y2K Info Previous Table of Contents Next 1-4Wiring Strategies in the Age of Multimedia LYNN HABER Multimedia is the next evolution in desktop computing. As the application of this technology matures and its business benefits are well understood, working with multiple data types—text, still images, video, and voice—will be commonplace. In the meanwhile, rethinking the organization’s premises infrastructure and local area networks (LANs) to accommodate future application requirements is an imperative for most businesses. Internet technology has been a shot in the arm for multimedia. Jazzy images abound in corporate Web sites, and usersí expectations are changing. Intranets, based on Internet technology and protocols, are capturing the attention of corporate information technology managers. Intranets are so attractive because they provide companies a way to reach a greater number of users without the complexity, high cost, or the administrative and management burden associated with a three-tier client/server architecture. They will, however, impact network performance. Working with multiple data types—text, still images, video, and voice—will continue to be a growing phenomenon across the enterprise. Rethinking the organization’s premises infrastructure and local area networks to accommodate future application requirements is an imperative for most businesses. ADAPTING EXISTING LANS FOR MULTIMEDIA Few current networks are up to speed for true networked multimedia, primarily because video requires isochrony, or the timed delivery of data to avoid voice and video delays during transmission. Today’s Ethernet and Token Ring network technology is characterized by bursty transmissions, which can result in unacceptable delays for the delivery of voice and video information. In other words, networked multimedia client/server applications over existing LANs are not guaranteed bandwidth. However, vendors are working on technology improvements and standards to enable desktop videoconferencing on the LAN, such as H.323, which addresses LAN infrastructure constraints. Multimedia applications exist today that can be accommodated on existing Ethernet and Token Ring networks. By making small modifications to existing LANs, at little expense, multimedia applications can be prototyped and even deployed. Infrastructure Requirements for Voice and Video Applications Delivery of multimedia information to the desktop is currently limited in the sense that it is best done in a store-and-forward fashion rather than in real time or interactively. Several vendors market real-time multimedia solutions for desktop videoconferencing, for example. Although such solutions are beneficial to the organizations that use them, largely because of the savings in travel expenses and workers’ time away from the office, the quality of the video is usually less than 15 frames per second at 320 × 240 pixels (or about one-quarter of a screen) compared with 30 frames per second for broadcast-quality video. Examples of multimedia applications being used today include: •  Annotated mail and documents. •  Collaborative computing. •  Desktop videoconferencing. •  News bulletins on the desktop. •  Image and video archives. •  Kiosks. •  Process control, monitoring, and training just-in-time processes in manufacturing. Today, graphics and images are the most common elements in multimedia applications, but the incorporation of voice and video is around the corner, so organizations rethinking the network must consider the inclusion of all multimedia elements. As business applications evolve to incorporate voice and video, file sizes will have bandwidth requirements from kilobytes to megabytes, even with compression. Assuming that image size, in pixels, is at standard VGA resolution (i.e., 640 × 480), for example, a one-page business letter uncompressed requires 5K bits; the file compressed 4:1 requires 1.3K bits. Compare that to a 24-bit computer image that requires uncompressed 800M bits and 8M bits when compressed 100:1 (the Joint Photographic Experts Group, or JPEG, standard), or to full-motion video at 45M bps uncompressed (the current NTSC standard for color television) and 1M bps when compressed at 50:1 (the Moving Pictures Experts Group, or MPEG, standard). Exhibit 1-4-1 lists bandwidth requirements for transmitting everything from simple documents, to faxes, to high-definition television (HDTV) images. Exhibit 1-4-1.  Bandwidth Requirements for Information Transfer Previous Table of Contents Next Use of this site is subject certain Terms & Conditions. Copyright (c) 1996-1999 EarthWeb, Inc.. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of EarthWeb is prohibited. Please read our privacy policy for details.