计算机网络与因特网论文.doc
《计算机网络与因特网论文.doc》由会员分享,可在线阅读,更多相关《计算机网络与因特网论文.doc(67页珍藏版)》请在沃文网上搜索。
1、计算机网络与因特网论文作 者:学 号:院 系: 专 业: 题 目: 指导者: 评阅者: CataloguePreface3Basics5Ultra-High-frequency communication (100 MHz)5Home networking (LAN)6Internet access (broadband over powerlines)8Medium frequency (kHz)10Low-speednarrow-band communication11High-speed narrow-band powerline communication distribution l
2、ine carrier13Transmitting radio programs14Utility applications15Low frequency (kHz)16Broadband over power line (BPL)17notching out and dynamic adaptation to contention18Interference issue remains a challenge to PLC systems19Automotive uses21Failure Scenarios21IEEE P1901, ITU G.hn home grids22Standar
3、ds organizations24Small and medium-sized enterprise office LAN construction scheme25Personal feeling30Reference directory32PrefaceThis article is now in its fourth edition. Each edition has corresponded to a different phase in the way computer networks were used. When the first edition appeared in 1
4、980, networks were an academic curiosity. When the second edition appeared in 1988, networks were used by universities and large businesses. When the third edition appeared in 1996, computer networks, especially the Internet, had become a daily reality for millions of people. The new item in the fou
5、rth edition is the rapid growth of wireless networking in many forms. The networking picture has changed radically since the third edition. In the mid-1990s, numerous kinds of LANs and WANs existed, along with multiple protocol stacks. By 2003, the only wired LAN in widespread use was Ethernet, and
6、virtually all WANs were on the Internet. Accordingly, a large amount of material about these older networks has been removed. However, new developments are also plentiful. The most important is the huge increase in wireless networks, including 802.11, wireless local loops, 2G and 3G cellular network
7、s, Bluetooth, WAP, i-mode, and others. Accordingly, a large amount of material has been added on wireless networks. Another newly-important topic is security, so a whole chapter on it has been added. Many people helped me during the course of the fourth edition. I would especially like to thank the
8、following people: Ross Anderson, Elizabeth Belding-Royer, Steve Bellovin, Chatschik Bisdikian, Kees Bot, Scott Bradner, Jennifer Bray, Pat Cain, Ed Felten, Warwick Ford, Kevin Fu, Ron Fulle, Jim Geier, Mario Gerla, Natalie Giroux, Steve Hanna, Jeff Hayes, Amir Herzberg, Philip Homburg, Philipp Hosch
9、ka, David Green, Bart Jacobs, Frans Kaashoek, Steve Kent, Roger Kermode, Robert Kinicki, Shay Kutten, Rob Lanphier, Marcus Leech, Tom Maufer, Brent Miller, Shivakant Mishra, Thomas Nadeau, Shlomo Ovadia, Kaveh Pahlavan, Radia Perlman, Guillaume Pierre, Wayne Pleasant, Patrick Powell, Thomas Robertaz
10、zi, Medy Sanadidi, Christian Schmutzer, Henning Schulzrinne, Paul Sevinc, Mihail Sichitiu, Bernard Sklar, Ed Skoudis, Bob Strader, George Swallow, George Thiruvathukal, Peter Tomsu, Patrick Verkaik, Dave Vittali, Spyros Voulgaris, Jan-Mark Wams, Ruediger Weis, Bert Wijnen, Joseph Wilkes, Leendert va
11、n Doorn, and Maarten van Steen. Special thanks go to Trudy Levine for proving that grandmothers can do a fine job of reviewing technical material. Shivakant Mishra thought of many challenging end-of-chapter problems. Andy Dornan suggested additional readings for Chap. 9. Jan Looyen provided essentia
12、l hardware at a critical moment. Dr. F. de Nies did an expert cut-and-paste job right when it was needed. My editor at Prentice Hall, Mary Franz, provided me with more reading material than I had consumed in the previous 7 years and was helpful in numerous other ways as well. Finally, we come to the
13、 most important people: Suzanne, Barbara, and Marvin. To Suzanne for her love, patience, and picnic lunches. To Barbara and Marvin for being fun and cheery all the time (except when complaining about awful college textbooks, thus keeping me on my toes). BasicsAll power line communications systems op
14、erate by impressing a modulated carrier signal on the wiring system. Different types of powerline communications use different frequency bands, depending on the signal transmission characteristics of the power wiring used. Since the power wiring system was originally intended for transmission of AC
15、power, in conventional use, the power wire circuits have only a limited ability to carry higher frequencies. The propagation problem is a limiting factor for each type of power line communications. A new discovery called E-Line that allows a single power conductor on an overhead power line to operat
16、e as a waveguide to provide low attenuation propagation of RF through microwave energy lines while providing information rate of multiple Gbps is an exception to this limitation.Data rates over a power line communication system vary widely. Low-frequency (about 100-200kHz) carriers impressed on high
17、-voltage transmission lines may carry one or two analog voice circuits, or telemetry and control circuits with an equivalent data rate of a few hundred bits per second; however, these circuits may be many miles long. Higher data rates generally imply shorter ranges; a local area network operating at
18、 millions of bits per second may only cover one floor of an office building, but eliminates installation of dedicated network cabling.Ultra-High-frequency communication (100 MHz)The highest information rate transmissions over power line use RF through microwave frequencies transmitted via a transver
19、se mode surface wave propagation mechanism that requires only a single conductor (US patent 7,567,154). An implementation of this technology called E-Line has been demonstrated using a single power line conductor. These systems have demonstrated symmetric and full duplex communication well in excess
20、 of 1 Gbit/s in each direction. Multiple WiFi channels with simultaneous analog television in the 2.4 and 5.3 GHz unlicensed bands have been demonstrated operating over a single medium voltage line conductor. Because the underlying propagation mode is extremely broadband, it can operate anywhere in
21、the 20MHz - 20GHz region. Also since it is not restricted to 80 MHz, as is the case for high-frequency BPL, these systems can avoid the need to share spectrum with other licensed or unlicensed services and can completely avoid the interference issues associated with use of shared spectrum while offe
22、ring complete flexibility for modulation and protocols of a RF-microwave system.High frequency communication may (re)use large portions of the radio spectrum for communication, or may use select (narrow) band(s), depending on the technologyHome networking (LAN)A LAN is a system of computers and asso
23、ciated peripherals such as Printers that are physically connected by cable within a limited geographical area-typically in an office building or on a college campus. The topology of the network may be ring, star or bus. LANs use fiber optics or coaxial cable to connect computers, and each computer m
24、ust have special communications software installed oil its hard disk. Software has been developed that allows computers with different platforms to coexist and exchange data on the same LAN. Power line communications can also be used in a home to interconnect home computers (and networked peripheral
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
10 积分
下载 | 加入VIP,下载更划算! |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 计算机网络 因特网 论文