NETWORK WORLD NEWSLETTER: STEVE TAYLOR AND JOANIE WEXLER ON WIDE AREA NETWORKING 09/02/04 Today's focus: Bandwidth efficiency in packet switching
Dear [EMAIL PROTECTED], In this issue: * Bandwidth efficiency took on new dimension with packet ��switching * Links related to Wide Area Networking * Featured reader resource _______________________________________________________________ This newsletter is sponsored by Oracle An Economist Intelligence Unit White Paper: From Grid to Great? Grid computing is breaking out. Familiar mostly to academics, government groups, and scientific researchers, this technology that links together the power of diverse computers to create powerful, fast and flexible systems is beginning to catch on in the corporate world. Included in this white paper, results and interviews from a global survey among Sr Executives, click to download now http://www.fattail.com/redir/redirect.asp?CID=78723 _______________________________________________________________ IS SECURITY RIPE FOR OUTSOURCING? Security demands for online applications such as e-commerce and Web services are prompting more corporate customers to hand off security functions - such as intrusion detection and firewalls - to outside service providers. Find out if security should be outsourced in this Network World article: http://www.fattail.com/redir/redirect.asp?CID=78286 _______________________________________________________________ Today's focus: Bandwidth efficiency in packet switching By Steve Taylor and Joanie Wexler As we mentioned last time, there was an entire industry built around using TDM bandwidth efficiently due to the compelling economics of building corporate private-line networks. By the late 1980s, however, packet switching technologies, ranging from "statistical multiplexers" to frame relay to ATM, began to take off. In particular, these devices started taking advantage of the asynchronous nature of data traffic. By "asynchronous," we mean that there are gaps between transmissions, and these gaps can be filled in by traffic from other data sessions. The industry was waiting for the electronics industry to develop sufficiently fast and cheap chips to make this level of additional processing economical. By a different measure, this asynchronous transmission, generically called packet switching, marked a shift in emphasis to a different type of "bandwidth efficiency." As we pointed out last time, it's nearly impossible to beat the efficiency of a T-1 carrying PCM voice, assuming that all conversations are connected continuously. However, the efficiency of TDM transmission comes into question when there are gaps in the traffic. With TDM, the bandwidth is reserved whether it's needed or not. Thus, we have the beginning of controversy as to whether packet switching is more "efficient." And exact calculations have to be given up in favor of suppositions. Where TDM transmission is better than 99% efficient for a constant data stream, packet streams have what must be referred to as "variable efficiency." The lighter the traffic and the larger the packets, the more efficient they are. For instance, frame relay has a minimum of five, eight-bit bytes (octets) of overhead per frame. So if you're only transmitting five bytes of information as the payload, you have 100% overhead - or only 50% efficiency. As the packets get larger, the efficiency gets better. If you have 95 bytes to transmit in the payload, you're up to 95% efficiency for that particular packet. But the real "bandwidth efficiency" here comes from the ability to share bandwidth among multiple data sessions. Even though the per-packet bandwidth efficiency is reduced, the aggregate efficiency is increased. But this timeframe also marked the beginning of the "battle of the protocols." In particular, a major defining characteristic of frame relay, ATM, and IP is the efficiency with which these protocols transport information. More and more, these efficiency arguments are starting to fade into oblivion. We'll tell you why next time. _______________________________________________________________ To contact: Steve Taylor and Joanie Wexler Steve Taylor is President of Distributed Networking Associates and Publisher/Editor-in-Chief of Webtorials.Com. For more detailed information on most of the topics discussed in this newsletter, connect to Webtorials.Com <http://www.webtorials.com/>, the first Web site dedicated exclusively to market studies and technology tutorials in the Broadband Packet areas of Frame Relay, ATM, and IP. He can be reached at <mailto:[EMAIL PROTECTED]> Joanie Wexler is an independent networking technology writer/editor in California's Silicon Valley who has spent most of her career analyzing trends and news in the computer networking industry. She welcomes your comments on the articles published in this newsletter, as well as your ideas for future article topics. Reach her at <mailto:[EMAIL PROTECTED]>. _______________________________________________________________ This newsletter is sponsored by Alterpoint Read the latest analyst report on Network Change and Configuration Management (NCCM) written by EMA's Dennis Drogseth. This report discusses the latest developments in the NCCM market, including an in-depth look at DeviceAuthority Suite, a comprehensive solution for configuring, changing, and controlling today's complex, multi-vendor IT network infrastructures. Download the report today to learn how you can leverage NCCM to reduce the cost and complexity of managing network change. http://www.fattail.com/redir/redirect.asp?CID=78702 _______________________________________________________________ ARCHIVE LINKS Archive of the WAN newsletter: http://www.nwfusion.com/newsletters/frame/index.html _______________________________________________________________ FEATURED READER RESOURCE CHECK OUT NW FUSION'S NEW WHITE PAPER LIBRARY NW Fusion's White Paper Library was recently re-launched with new features and improved capabilities! Sort NW Fusion's library of white papers by Date and Vendor, view white papers by TECHNCIAL CATEGORY, mouse over white paper descriptions and take advantage of our IMPROVED white paper search engine. CLICK HERE: <http://www.nwfusion.com/vendorview/whitepapers.html> _______________________________________________________________ May We Send You a Free Print Subscription? 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