1、ays especially for best effort TCP/IP traffic. The large delays in GEOs, and delay variations in LEOs, affect both real time and non-real time applications. Many real time applications are sensitive to the large delay experienced in GEO systems, as well as to the delay variation experienced in LEO s
2、ystems. In an acknowledgment and timeout based congestion control mechanism (like TCP), performance is inherently related to the delay-bandwidth product of the connection. Moreover, TCP Round Trip Time (RTT) measurements are sensitive to delay variations that may cause false timeouts and retransmiss
3、ions. As a result, the congestion control issues for broadband satellite networks are somewhat different from those of low latency terrestrial networks. Both interoperability, as well as performance issues between satellite and terrestrial networks must be addressed before data, voice and video serv
4、ices can be provided over a Satellite-ATM network.This report provides a survey of the issues involved in designing satellite-ATM networks for transporting data traffic, especially TCP/IP traffic. The report first provides an introduction to the satellite-ATM architectural issues, and presents a ref
5、erence architecture for satellite-ATM networks. The report then discusses the error characteristics of satellite channels and presents techniques to improve the error characteristics. The report then discusses the implementation and performance of TCP/IP over the UBR and ABR service categories. The
6、focus of this report is to present the issues involved, to make recommendations in the design of satellite-ATM networks.2 Architectural IssuesIn this section we present the basic architectural issues for ATM over Satellite. A reference architecture is presented, and a summary of the need to support
7、the various ATM service categories is givenhighlighted.52.1 A Reference Architecture for Satellite-ATM NetworksFigure 1 illustrates a satellite-ATM network represented by a ground segment, a space segment, and a network control center. The ground segment consists of ATM networks that may be further
8、connected to other legacy networks. The network control center (NCC) performs various management and resource allocation functions for the satellite media. Inter-satellite links (ISL) in the space segment provide seamless global connectivity to the satellite constellation. The network allows the tra
9、nsmission of ATM cells over satellite, multiplexes and demultiplexes ATM cell streams from uplinks and downlinks, and maintains the QoS objectives of the various connection types. The satellite-ATM network also includes a satellite-ATM interface device connecting the ATM network to the satellite sys
10、tem. The interface device transports ATM cells over the frame based satellite network, and demultiplexes ATM cells from the satellite frames. The device typically can uses a DAMA technique to obtain media access to the satellite physical layer. The interface unit is also responsible for forward erro
11、r correction techniques to reduce the error rates of the satellite link. The unit must maintain ATM quality of service parameters at the entrance to the satellite network. As a result, it translates the ATM QoS requirements into corresponding requirements for the satellite network. This interface is
12、 thus responsible for resource allocation, error control, and traffic control. Details about this model can be obtained from KOTA97. the reference model from TIA/EIA/TSB-91 should be usedThis architectural model presents several design options for the satellite and ground network segments. These opt
13、ions include No on-board processing or switching. On-board processing with ground ATM switching. On-board processing and ATM switching.About 53% of the planned Ka-band satellite networks propose to use on-board ATM like fast packet switching PONZ97. An overview of the network architectures of some o
14、f the proposed systems can be found in WUPI94. In a simple satellite model without on-board processing or switching, minimal on-board buffering is required. However, if on-board processing is 6performed, then on-board buffering is needed to achieve the multiplexing gains provided by ATM. On-board pr
15、ocessing can be used for resource allocation and media access control (MAC). MAC options include TDMA, FDMA, and CDMA and can use contention based, reservation based, or fixed media access control. Demand Assignment Multiple Access (DAMA) KOTA97b can be used with any of the MAC options. If on-board
16、processing is not performed, DAMA must be done by the NCC. On-board DAMA decreases the response time of the media access policy by half because link access requests need not travel to the NCC on the ground any more. In addition to media access control, ABR explicit rate allocation or EFCI control, a
17、nd UBR/GFR buffer management can also be performed on-board the satellite. On-board switching may be used for efficient use of the network by implementing adaptive routing/switching algorithms. Trade-offs must be made with respect to the complexity, power and weight requirements for providing on-boa
18、rd buffering, switching and processing features to the satellite network. In addition, on-board buffering and switching will introduce some additional delays within the space segment of the network. For fast packet or cell switched satellite networks, the switching delay is negligible compared to th
19、e propagation delay, but the buffering delay can be significant. Buffering also results in delay variations due to the bursty nature of ATM traffic. Figure 1: Satellite-ATM network modelSatellite-ATM network architectures present tradeoffs in cost/complexity and on-board switching/processing capabil
20、ities.72.2 Service Categories in ATM NetworksATM networks carry traffic from multiple service categories, and support Quality of Service (QoS) requirements for each service category. The ATM-Forum Traffic Management Specification 4.0 TM4096 defines five service categories for ATM networks. Each serv
21、ice category is defined using a traffic contract and a set of QoS parameters. The traffic contract is a set of parameters that specify the characteristics of the source traffic. This defines the requirements for compliant cells of the connection. The QoS parameters are negotiated by the source with
22、the network, and are used to define the expected quality of service provided by the network. For each service category, the network guarantees the negotiated QoS parameters if the end system complies with the negotiated traffic contract. For non-compliant traffic, the network need not maintain the Q
23、oS objective. The Constant Bit Rate (CBR) service category is defined for traffic that requires a constant amount of bandwidth, specified by a Peak Cell Rate (PCR), to be continuously available. The network guarantees that all cells emitted by the source that conform to this PCR will be transferred
24、by the network with minimal cell loss, and with旼旼42 2.1.2.1 设备投资占比 38.53% 2.1.3 其它投资万元 1579.70 2.1.3.1 其它投资占比 8.88% 2.1.4 固定资产投资占比 76.34% 2.2 流动资金万元 4208.54 2.2.1 流动资金占比 23.66% 3 收入万元 34777.00 4 总成本万元 26655.21 5 利润总额万元 8121.79 6 净利润万元 6091.34 7 所得税万元 1.27 8 增值税万元 1120.25 9 税金及附加万元 350.96 10 纳税总额万元 3
25、501.66 11 利税总额万元 9593.00 12 投资利润率 45.66% 13 投资利税率 53.94% 14 投资回报率 34.25% 15 回收期年 4.42 16 设备数量台（套） 165 17 年用电量千瓦时 1321221.11 18 年用水量立方米 21502.96 19 总能耗吨标准煤 164.22 20 节能率 28.48% 泓域咨询MACRO/ TOC测定仪项目立项申请报告 21 节能量吨标准煤 46.32 22 员工数量人 573 1鮋鬐鮫鯫1鮬鯌鮝1鯝鯽鮾鯮鮏鮿1預1謐1鼐11鰐11蠐111踀騁帰阀倁 US.A. $24.95 CAN. $31.00 The Ki
26、ngkiller Chronicle: Day One My name is Kvothe, pronounced nearly the same as “quothe.“ Names are important as they tell you a great deal about a person. IVe had more names than anyone has a right to. The Adem call me Maedre. Which, depending on how its spoken, can mean The Flame, The Thunder, or The
27、 Broken Tree. “The Flame“ is obvious if youve ever seen me. I have red hair, bright. If I had been born a couple of hundred years ago I would probably have been burned as a demon. I keep it short but its unruly. When left to its own devices, it sticks up and makes me look as if I have been set afire
28、. “The Thunder“ I attribute to a strong baritone and a great deal of stage training at an early age. Ive never thought of “The Broken Tree“ as very significant. Although in retrospect, I suppose it could be considered at least partially prophetic. My first mentor called me Elir because I was clever
29、and I knew it. My first real lover called me Dulator because she liked the sound of it. I have been called Shadicar, Lightfinger, and SixString. I have been called Kvothe the Bloodless, Kvothe the Arcane, and Kvothe Kingkiller. I have earned those names. Bought and paid for them. But I was brought u
30、p as Kvothe. My father once told me it meant “to know.“ I have, of course, been called many other things. Most of them uncouth, although very few were unearned. (continued on back flap) (continued from front flap) I have stolen princesses back from sleeping barrow kings. I burned down the town of Tr
31、ebon. I have spent the night with Felurian and left with both my sanity and my life. I was expelled from the University at a younger age than most people are allowed in. I tread paths by moonlight that others fear to speak of during day. I have talked to Gods, loved women, and written songs that mak
32、e the minstrels weep. You may have heard of me. So begins the tale of Kvothefrom his child hood in a troupe of traveling players, to years spent as a near-feral orphan in a crime-riddled city, to his daringly brazen yet successful bid to enter a difficult and dangerous school of magic. In these page
33、s you will come to know Kvothe as a notorious magician, an accom* plished thief, a masterful musician, and an infamous assassin. But is so much morefor the story it tells reveals the truth behind Kvothes legend. currently lives in central Wisconsin where he teaches at the local university. In his fr
34、ee time Pat writes a satirical humor column, practices civil disobedience, and dabbles in alchemy. He loves words, laughs often, and refuses to dance. is his first novel. There will be more. Jacket painting by Donato Jacket designed by G-Force Design Photo by Jamie Rothfuss “ marks the debut of a w
35、riter we would all do well to watch. has real talent, and his tale of Kvothe is deep and intricate and wondrous.“ Terry Brooks, 22-time New York Times bestselling author “ has everything fantasy readers like, magic and mysteries and ancient evil, but its also humorous and terrifying and completely b
36、elievable. As with all the very best books in our field, its not the fantasy trappings (wonderful as they are) that make this novel so good, but what the author has to say about true, common things, about ambition and failure, art, love, and loss.“ Tad Williams New York Times bestselling author of S
37、hadowmarch, Otherland, and Memory, Sorrow and Thorn “Hail ! A new giant is striding the land. is an astonishing novel that just happens to be the writers first. The bestsellers lists and the award ballots are beckoning toward Rothfuss, and readers will be clamoring for more of the riveting life stor
38、y of Kvothe. Bravo, I say! Bravo!“ Robert J. Sawyer, Hugo Award-winning author of Rollback “ gives us a fabulous debut, standing firmly on the main stage of the fantasy genre and needing no warm-up act. Jordan and Goodkind must be looking nervously over their shoulders!“ Kevin J. Anderson, New York
39、Times bestselling coauthor of Hunters of Dune “ is a rare find these days, fit for lovers of fantasy and newcomers to the genre alike. It fires the imagination and stirs the heart. In Pat Rothfusss sure hands, the reader will experience a journey to the very heights of fantasy. I for one never wante
40、d to come back down.“ Sean Williams, New York Times bestselling author of The Blood Debt ISBN 13: 978-0-7564-0407-9 52495 9“780756“404079 THE KINGKILLER CHRONICLE: DAY ONE DAW BOOKS, INC. DONALD A. WOLLHEIM, FOUNDER 375 Hudson Street, New York, NY 10014 ELIZABETH R. WOLLHEIM SHEILA E. GILBERT PUBLIS
41、HERS http:/ Copyright 2007 by All rights reserved. Jacket art by Donato. DAW Books Collectors No. 1396. DAW Books are distributed by Penguin Group (USA) Inc. Book designed by Elizabeth Glover. Maps by Nathan Taylor www.king- All characters and events in this book are fictitious. All resemblance to persons living or dead
