 BPL's ten- dency to interfere with ham radio, a consideration that will be taken up by the FCC. When BPL devices are installed on underground power lines, the signal is shielded by the conduit and is unlikely to cause inter- ference to other communications services. IP and MPLS It would be irresponsible to publish this book without detailed coverage of the next generation of transport network that is currently emerging. While frame relay and ATM continue to be important technologies for Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Transport Technologies Chapter 7 switched-broadband transport, they are expensive, complex, and cum- bersome to operate. And given the degree to which IP has taken the lead position in networking discussions today, it makes sense that IP should have its space, particularly given the fact that it is now being deployed in conjunction with Multiprotocol Label Switching (MPLS) as a carrier- grade, layer three network infrastructure that offers truly granular QoS. We begin with a discussion of the remarkable protocol suite called TCP/IP and how it works. The Internet as we know it today began as a DoD project designed to interconnect DoD research sites. In December of 1968, the govern- ment research agency known as the Advanced Research Projects Agency (ARPA) awarded a contract to Bolt, Beranek, and Newman (BBN) to design and build the packet network that would ultimately become the Internet. It had a proposed transmission speed of 50 Kbps, and in September of 1969 the first node was installed at UCLA. Other nodes were installed on roughly a monthly basis at Stanford Research Institute (SRI), the University of California at Santa Barbara (UCSB), and the University of Utah. The ARPANET spanned the continental United States by 1971 and had connections to research facilities in Europe by 1973. The original protocol sele