1Introduction
高二英语必修5(外研版)4-1Introduction
外 研 版 英 语
Module 4
Carnival
词语辨析 celebrate; congratulate celebrate和congratulate本非同义词，但都相当于 汉语“庆贺”的意思。congratulate“庆祝”后面只能 以“被庆贺的人”作宾语，它的句型是：congratulate sb.(on sth.)。
Module 4
Carnival
外 研 版 英 语
必修⑤
Module 4
Carnival
外 研 版 英 语
必修⑤
Module 4
Carnival
hide, confusion, extend, pretend, revive, book, wander, elegant, 核心 magic, relaxing, whistle, tasty, parade, multicultural, plantation, mark, trade, transport, import, master, abolish, magnificent, celebration, freedom, unite, origin come to an end, consist of, dress up 核心 祈使句＋and＋简单句(教材P32)
外 研 版 英 语
必修⑤
第一课时
Module 4
Carnival
即学即用 Please make a________where you think there are mistakes in the composition. A．sign C．mark 答案：C B．signal D．remark
外 研 版 英 语
考研 1 introduction_of_Linguistics
Arbitrariness ---任意性，最先由
Saussure提出，语言学之父。 Arbitrary relationship between the sound of a morpheme and its meaning.
Duality（二重性） 语言是层级性的，主要是由
syllables morphemes word phrase sentence discourse这么个系统组成的。 (浙大）问答题：Explain what the term duality means as it is used to describe a property of human lg.
讲义一 Introduction to Linguistics
Grace Tan
T/F
1.The relation between form and meaning in human
language is natural. 2.When lg is used to get information from others , it serves an informative function. 3.The reason for French to use Cheval and English to use horse to refer to the same animal is inexplicable. 4.Most animal communication systems lack the primary level of articulation. 5.Halliday′s linguistic potential is similar to the notions of parole and performance. 6.Descriptive linguistics are concerned with how lgs work, not with how they can be improved.
高二英语选修6(外研版)课件2-1Introduction
Module 2
Fantasy Literature
2．hero n．(pl.～es)男主角，男主人公；英雄，偶像
①He's the hero of the novel. 他是该小说的男主人公。 ②We all think of him as a hero. 我们都认为他是英雄。 ③You're my hero. 你是我心中的偶像。
Module 2
Fantasy Literature
外 研 版 英 语
Module 2
Fantasy Literature
外 研 版 英 语
Module 2
类别
Fantasy Literature
课程目标要求掌握的项目
话题
fantasy literature and fiction stories
外 研 版 英 语
_________________________
答案：He likes a life full of adventure.
Module 2
Fantasy Literature
外 研 版 英 语
Module 2
Fantasy Literature
play a part
1)扮演某个角色 ①Who plays the part of Macbeth? 谁扮演麦克白？ ②He will play an important part in the film. 他将在这部电影中扮演一个重要的角色。 2)担任……任务/职务 He played a leading part in the movement.
外 研 版 英 语
Module 2
Fantasy Literature
1-introduction (s)(1-简介)
Marketing is so much more than that!（营销远 不止这些）
Packaging（包装） Strategy（策略） Competitive Strategies（竞 Sales, Sales-force 争优势） （销售，销售队伍） Market Penetration（市场 Brand Management 渗透） （品牌管理） Quality（质量）
Meaning:
Creating customer value and satisfaction are at the heart of modern marketing thinking A very simple definition of marketing is the delivery of customer satisfaction at a profit. Goals of marketing are to attract new customers by promising superior value and to keep and grow current customers by delivering satisfaction. Marketing is much more than selling and advertising. It is about understanding and satisfying customer needs.
Logistics（物流） Location（定位） Distribution Channels（分销渠道） Pricing Considerations（价格策略）
Globalization（全球化）
New Product Develop（新产品开发） Service Delivery（服务交付）
1Introduction
主要内容 (Outline)• 绪论小规模集成电路三（SSI）• 逻辑函数基础 门电路个• 组合逻辑电路模 块中规模集成电路 （MSI）• 集成触发器 • 时序逻辑电路大规模集成电路 • 半导体存储器（LSI）• 数模、模数转换电路绪论 (Introduction)一、数字(digital)信号和模拟(analog)信号 数字量和模拟量 数字电路和模拟电路二、数字信号相关概念 二进制数 Binary Digits 数字信号的逻辑电平 Logic Levels 数字信号波形 Digital Waveforms一、Digital Signal and Analog Signal Digital and Analog Quantities电子 电路 中的 信号模拟信号: 连续analogue signal value数字信号: 离散digital signal valuetime time模拟信号T( C) 30采样信号T( C)sampled3025离散化 2520202 4 6 8 10 12 2 4 6 8 10 12 t (h)A.M.P.M.2 4 6 8 10 12 2 4 6 8 10 12 t (h)A.M.P.M.数字化－表示 为由0、1组成 的二进制码Analog Electronic SystemDigital and Analog Electronic System★ 工作在模拟信号下的电子电路是模拟电路。
研究模拟电路时，注重电路输入、输出信号 间的大小、相位关系。
包括交直流放大器、 滤波器、信号发生器等。
★ 模拟电路中，晶体管一般工作在放大状态。
★ 工作在数字信号下的电子电路是数字电路。
研究数字电路时，注重电路输出、输入间的逻 辑关系。
主要的分析工具是逻辑代数，电路的 功能用真值表、逻辑表达式或波形图表示。
★ 在数字电路中，三极管工作在开关状态， 即工作在饱和状态或截止状态。
高一英语必修3(外研版)课件6-1Introduction
Module 6 Old and New
2．accommodate vt. 接待；容纳；为„„提供住宿
① The bus is large enough to accommodate 50 passengers. 这辆巴士可以容纳50名乘客。 ②The hall can only accommodate 200 people. 这个大厅只能容纳200人。 ③This hotel can accommodate 500 guests. 这旅馆可供500名旅客住宿。
外 研 版 英 语
5)形容词＋形容词
aural-oral practice a grey-green roof
Module 6 Old and New
6)形容词＋名词 high-class officials 高级官员们 7)形容词＋现在分词 a good-looking man 一个相貌好看的男人 8)形容词＋过去分词
Difficulties in language communication： It's absolutely enormous！ It was freezing. It's wonderful. I'm astonished. Non-defining relative clauses Contraction of relative clauses The Yangtze River, which is more than 6,000 kilometres long, is the third longest river in the world. The people living in the village have moved to other places.
introduction用法
introduction用法
Introduction是一个英语单词，它的中文意思是“介绍”或“引言”。
它可以用作名词，也可以用作动词。
作为名词，Introduction通常指的是一篇文章、一本书或一场演讲的
开头部分。
在这个部分中，作者或演讲者会介绍自己的主题、目的和
观点。
Introduction也可以指一个人或一件事物的简介或概述。
作为动词，Introduction表示“介绍”、“引进”、“推出”等意思。
例如，“我们将在下个月Introduction新产品。
”这句话的意思是“我们将在下个月推出新产品。
”
除此之外，Introduction还有其他一些常见用法：
1. Introduction to：表示“对……进行介绍”。
例如，“我将对这个
项目进行简短的Introduction。
”
2. Self-introduction：表示“自我介绍”。
例如，“请允许我进行一
下Self-introduction。
”
3. Introduction letter：表示“介绍信”。
例如，“我需要你写一封
Introduction letter给我的未来雇主。
”
4. Introduction course：表示“入门课程”。
例如，“这是一个适合初学者的Introduction course。
”
总之，无论是作为名词还是动词，Introduction都是一个非常常见且重要的单词，在日常生活和工作中都有广泛应用。
高二英语必修5(外研版)6-1Introduction
必修⑤
第一课时
Module 6
Animals in danger
即学即用 完成句子 恐龙已经绝种几百万年了。 Dinosaurs ________ ________ ________for millions of years.
外 研 版 英 语
答案：have been extinct
必修⑤
第一课时
外 研 版 英 语
Module 6
Animals in danger
知识拓展 1)protect sb./sth. from sth. 保护„„使不受„„ protect sb./sth. against sth. 防止„„遭受„„ protect sb./from danger 保护某人免遭危险
核心语法 复习定语从句
必修⑤
Module 6
Animals in danger
外 研 版 英 语
必修⑤
Module 6
Animals in danger
Steve Jones is an environmental expert who① tries to
keep animals and plants from② becoming endangered. “We are not alone in the world. We human beings could not survive without all the plants and animals around us. We often talk about how important it is to take good care of
外 研 版 英 语
必修⑤
第一课时
Module 6
DigitalSignalProcessing(1Introduction)-讲义
DigitalSignalProcessing(1Introduction)-讲义About The CourseDigital Signal Processing SCUT Lecture 1 IntroductionIntroduction on DSP A/D D/A Conversion BibliographyTextbook: A.V. Oppenheim, R.W. Schafer, J.R. Buck, Discrete-time Signal Processing, Second Edition. Prentice Hall, 1999. Tsinghua University Press, 20XX年. References: S. K.Mitra, Digital Signal Processing: A Computer-based Approach, Second Edition. Mcgraw-hill, 20XX年. Tsinghua University Press, 20XX年. 程佩青编,《数字信号处理教程》(第二版),清华大学出版社, 20XX年SCUTSCUTDigital Signal Processing, 20XX年, Y.ZengYan Zeng South China University of Technology 20XX年SCUT第1页Digital Signal Processing, 20XX年, Y.Zeng第2页About The Course Instructor: Yan Zeng,C Phone: 8711 4480 (H), 189 **** ****C Office: Building#18 (412)C E-Mail: yzeng@, zengyan.gz@C E-Mail for submitting reports: scutoptics@ Grading PolicyCExercises and Reports: 20%CFinal exam: 80% Exercises and Reports: There are proper exercises, homeworks or reports every week, which must be delivered on every Wednesday.Digital Signal Processing, 20XX年, Y.Zeng第3页About The CourseSCUT眼界决定境界，视野决定胸怀，行动决定命运！广泛阅读，善于思考，勤于实践！仰望星空，脚踏实地！SCUTI will give you many careful and trenchant discussion on DSP theories, methods and a wild view to modern science and technoloty. Wish you have a great journey in the course!SCUTSCUTDigital Signal Processing, 20XX年, Y.Zeng第4页Chapter 1 Introduction Background Aim Motivation What is DSP Characteristics of DSP Basic Framework Main Application and Some Examples Sampling and Quantization( A/D D/A Conversion)1.1 BackgroundSCUT建安24年(公元219年)腊月，曹操与华佗。
高二英语必修5(外研版)1-1Introduction
必修⑤
第一课时
Module 1
British and American English
一言辨异 All of them went to the cinema except Tom. They all agreed that it was really a wonderful film except for its theme song. 除了汤姆以外他们都去看电影了。大家一致认为， 除了主题曲之外这部影片真是棒极了。
外 研 版 英 语
必修⑤
Module 1
British and American English
外 研 版 英 语
必修⑤
Module 1
British and American English
知识点击： ①come about 发生 ②at that time 在那时 ③later on 后来 ④to 语。 ⑤some of which引导非限制性定语从句，修饰先行 词words and accents of their own languages ⑥what 引导名词从句，作介词from的宾语。
外 研 版 英 语
必修⑤
第一课时
Module 1
British and American English
②Talking of money—it's really easy to exchange traveller's cheques at banks or hotels so I advise you to get some of those before you come. 谈到钱，在银行或饭店兑换旅行支票非常容易，所 以我建议您在来之前准备一些支票。
高一英语必修3(外研版)课件2-1Introduction
Module 2 Developing and developed countries
外 研 版 英 语
Module 2 Developing and developed countries
外 研 版 英 语
Module 2 Developing and developed countries
外 研 版 英 语
[误]His income is more than his wife's.
[正]His income is larger than his wife's.
Module 2 Developing and developed countries
知识拓展
be on a high/low income 高/低收入 live within one's income 量入为出 unearned income 非劳动收入；非工资收入
up to, at the top of, make sure, more than, make efforts, connect...with..., as a result, find out Difficulties in language communication ①How do you find it？ ②It's totally fascinating！ ③As you see(them)． ④I didn't get that. ⑤(Let's)find some of the action.
外 研 版 英 语
Module 2 Developing and developed countries
3．poverty n. (U)
(1)贫穷/困 She had been worn down by poverty and illness. 她贫病交加，受尽折磨。 (2)贫乏；缺乏/少 His work was criticized for its poverty of imagination. 他的作品因缺少想象力而受批评。
英美报刊选读1introduction
英国报刊
英国报刊发行与美国不尽相同，国内外财团控制的大报业集团的 报纸占全英发行量的90%，这些大集团以往又都是集中在伦敦市 中心的报业中心“舰队街”（Fleet Street）。因此，Fleet Street常用来借喻伦敦或英国“报界”或“新闻界”。现在为了 改善发行和促进在海外销售，有的已移往伦敦其他地区或城市， 甚至海外，如《卫报》就在德国发行国际版，而《金融时报》就 直接在德国、美国和日本等国印刷发行。英国报纸按风格和内容 分为quality /popular /mid-market papers, “质量类”报纸是严 肃性大开张（broadsheet）的全国性日报，有很高的编辑水平， 读者对象是受过较高教育的上层和中产阶级人士。Daily Express《每日快报》、Daily Mail《每日邮报》、Daily Mirror 《每日镜报》、Daily Star《每日明星报》、The Sun《太阳报》 都是“通俗类”小报，消息不如quality papers 那样严肃可靠， 往往追求轰动效应。如《太阳报》就以刊登英国王室成员和政界 人士的桃色新闻和美女照片而“著称”。其发行量居首位。读者 基本是工人阶级和中产阶级。“中间市场类”指介于这两者之间 的报纸。
American major news magazines
Time Newsweek Reader’s Digest Fortune Business Week Far Eastern Review 《时代》周刊 《新闻周刊》 《读者文摘》 《财富》杂志 《商业周刊 》 《远东经济评论》
American major news magazines
Major News Agencies
Major provider of news for newspapers, radios and TV stations
1 Introduction
HLP ImplementationVersion0.1International Computer Science Institute1IntroductionHybrid Link-State Path-Vector Protocol,or HLP,is an inter-domain routing protocol designed as a replacement for the current Border Gateway Protocol(BGP).Using a combination of link-state and path vector routing,it provides greater scalability,better fault isolation and better convergence.The core of HLP is the inclusion of the economic and political structure of the Internet into inter-domain routing.That is,BGP currently considers each AS as a node in a general graph without any specific structure(using explicit policies to constrain routing),whereas HLP assumes that the Internet structure is basically hierarchical with the provider autonomous systems(ASs)being the roots of customer ASs.HLP explicitly includes the relationship between2neighboring ASs in its protocol.This will reduce misconfigurations which should hopefully reduce the occurrence of routing abnormalities.However,the tradeoff is some amount of inflexi-bility in the routing algorithm.This is resolved using exceptions that are expected to be rare and therefore acceptable. This report summarizes implementation of HLP on the XORP[1]software router.The implementation reuses much of the code in XORP’s BGP module.2DefinitionsWe say that two ASs are in the same hierarchy if there exists a directed path between them such that the path consists of any number of provider links followed by any number of customer links.This definition of hierarchy implies that there exists at least one route between two ASs in a hierarchy that does not include(provider)(customer)(provider)links. Two ASs are neighbors if there exists a link between them.The relationship between neighboring ASs(peer,customer, or provider)determine the overall structure of the network,which can be as simple as shown in Figure1a,or consist of overlapping hierarchies as shown in Figure1b.In thefigure,each node represents an AS;the neighboring AS at a higher tier is the provider,similarly an AS at a lower tier is the customer.Thus,AS A is the provider of AS B,which in turn is A’s customer.Neighboring ASs at the same tier are also called peering ASs.Note that the use of tiers in Figure1and inprotocol.subsequentfigures only allows for graphical representation of relationships,it is not present in the actual HLPHLP divides the network into hierarchies consisting of providers and their customer ASs,and peering ASs in different hierarchies allow routing between hierarchies.As will be explained in the next section,this division of the network intoseparate components increases scalability,as well as reduces the convergence time for route updates.3Routing Information DisseminationTwo types of routing packets are used to disseminate routing information:link-state advertisements(LSAs)and fragmented path-vector(FPV)1.As is the case in OSPF,LSAs areflooded throughout a hierarchy,and allow construction of the entire hierarchy topology.FPVs are used to route between ASs;they contain the numbers of peering ASs between hierarchies. LSAs that have not previously been received are forwarded in the following manner:1.if they are from customers,we forward to all neighbors,except the customers from which they arrive.2.if they are from providers,we forward only to neighboring customers,not providers.The objective of the above rules is to restrict LSAs to the hierarchies from which they originate.Failure to do so will imply that multi-homing ASs belonging to different hierarchies can cause LSAs to be disseminated throughout the entire Internet. The rules above implements this restriction,illustrated in Figure2.By definition,AS C belongs to both hierarchies1and 2,and rule1allows LSAs from AS B to be forwarded to C.At C,rule2prevents LSAs from A from being forwarded to AS D.On the other hand,LSAs involving C will be disseminated in both hierarchies,which is correct since C is a member both.ofFPVs are used to forward routes from one hierarchy to another.They are similar to path-vector packets used in BGP,except that they do not include the AS path within hierarchies.Rules that govern forwarding of FPVs are given as follows:1.FPVs from providers are disseminated only to customers,not to peers or other providers.2.FPVs from peers are forwarded to neighboring peers and customers,but not providers.4Routing AlgorithmThe mechanism to choose a route to a particular destination AS is similar to that currently used in BGP.This eases the implementation of exceptions which will be covered in the next section,as well as the creation of FPVs for routes to customers within the hierarchy Basically,we store routes for destination ASs reachable from each neighboring AS,then decide the winning route for a particular destination.The handling of routes contained within FPVs is straightforward and similar to that of BGP,but routing information gained from LSAs needs to be converted to the same form as that in FPVs. The conversion is elaborated on in the next section.4.1From LSAs to RoutesWe denote the least cost of reaching AS A from B by cost(B,A),a route from A to B with cost C by route[(A,B),C], and we perform the conversion in the following manner,assuming that the operations are taking place in AS X:1.for each neighbor N2.if neighbor is a customer3.for each downstream customer AS Apute cost(N,A)5.create AS path[X,A]with cost C=[cost(N,A)+cost(X,N)]6.associate route[(X,A),C]with N7.else if neighbor is a provider8.for each of the non-customer ASs in the hierarchypute cost(N,A)10.create AS path[X,A]with cost C=[cost(N,A)+cost(X,N)]11.associate route[(X,A),C]with NThe computation is broken into two parts,steps2to5,and6to9of the algorithm above.This is required because forwarding of routes from a provider to a peer should take place only if the destination AS is a customer2.To distinguish between the origin of the routes,we tag them with the following:PROVIDERLSA:Route for non-customer destination AS within the same hierarchy,determined using link-state information.PEERLSA:Route for customer destination AS obtained using link-state information.An example is given in Figure3,where we focus on AS C.Table1shows the routes,costs and tags associated with each neighbor.Neighbor Cost(C,A)PROVIDERA3LSA(C,E)PROVIDERA15LSA(C,D)PROVIDERD26LSA(C,A)PROVIDERF5LSATable1:Table containing routes,costs and tags for example converting LSAs to routes4.2From FPV to RoutesCreation of routes from FPVs are much simpler,and is similar to that in BGP:1.if FPV is from a provider P2.extract route and metric,tag with PROVIDER_FPV,and associate them with P3.if FPV is from a peer Q4.extract route(prepending this AS’number)and metric,tag with PEER_FPV,and associate with Q5.if FPV is from customer,treat FPV as coming from peer,extract route(prepending this AS’number)and metric,tag with PEER_FPV,and associate with QNote that step5only occurs due to an exception in the customer AS.Figure3:Example illustrating LSA to route conversion4.3Route SelectionThe winning route to a particular destination is selected according to the following order of preferences:1.customer route(ie.tagged with CUSTOMERNeighbor TypePROVIDER CustomerFPVCUSTOMER PeerTable2:Route types that can be forwarded to corresponding neighboring AS types5ExceptionsHLP supports three different types of exceptions.The primary use of exceptions is to support operations that are currently used in BGP but not covered by the default HLP rules.The format in which exceptions are specified and stored is given by wherefromlink specifies the neighboring link to which winning routes will be propagated,andAS number refers to the destination AS that this particular exception is for.In HLP,a from link is given by the tuple:5.1Exception1Figure4:(a)Example illustrating effect of exception1on rest of hierarchy.D announces that it does not have a customer route to C.B uses graph in(b)to compute shortest paths to all ASs in the same hierarchy except C(i.e.A,D and F).B uses the graph in(c)to compute the shortest path to C.Thefirst exception,illustrated in Figure4,allows an AS(say D)to choose an alternate route to a customer(C)via a peer (E).The route choose is dependent on the customer AS,and should not affect routes to other ASs.D indicates its intention via LSAs to other ASs in the same hierarchy that it is not choosing customer routes to C.D also informs E that it no longer has a customer route to C.If,ignoring customer routes,the winning route is from E,then D forwards that FPV to its peers and customers.However,if the winning route is from another peer not specified in the exception,then the corresponding FPV will not be forwarded.Using the same example,exception1is specified bywhere is specified using the tuple5.2Exception2This exception specifies that winning routes from the stated provider is to be forwarded to a particular peer,which is typically not done.In Figure5,the exceptionallows winning routes to AS Z from provider A to be forwarded to D.5.3Exception3The last exception supported is similar to exception2.Here,routes are forwarded from a peer to a provider.Currently, the provider simply accepts incoming FPVs from customers,treating them as though they are from peers.If,for security reasons,providers should reject FPVs from customers,then additional configuration will be required in the provider.Figure5:Simple network illustrating route forwarding from provider to peer5.4Exception Format and MatchingThe type of exception does not explicitly need to be specified.Instead,the neighbor relationship associated with the links given in each exception rule can be used to determine this.The format is thus simplified,and should hopefully reduce the occurrence of misconfigurations.Table3gives the combination of links that indicate the kind of exception specified.From To Exception TypeNULL1PeerPeer3Table3:Combination of link types associated with each exception type6Data StructuresIn this section we describe the data structures used to maintain state in a HLP router.Figure6shows theflow of routing information through the system,as well as the major components of the system.Figure6:Flow of routing information through systemWe describe each component below:Peer:A peer contains the necessary objects needed for receiving and sending routing information from and to neighboring routers.Each peer maintains the state machine for the connection associated with the corresponding neighbor,as well as the various timers needed during connection establishment and for keepalive messages.RibIpcHandler:Handles insertion of prefixes owned by this AS.Routing Information Base Input Table(RibInTable):Stores routes associated with corresponding neighboring router.Routes may be obtained via FPVs sent from neighbor,or from computation of shortest paths using link-state infor-mation.The type of tag assigned to a route is explained in Section4.1.PeerHandler:Handles reception and transmission of FPVs and LSAs.After a packet has been received,it is broken up into individual components(for instance,link changes,route withdrawals,route announcements,etc.)before being passed to HLPCore for processing.Updates passed from the DecisionTable are aggregated as much as possible within a packet(FPV or LSA)before being transmitted.Routing Information Base Output Table(RibOutTable):Stores the outgoing routes sent via FPVs.The contents of this table is a subset of the corresponding RibInTable of the neighboring router.PeerData:Contains information related to the peering link:–neighbor’s AS number and identification number(ID),–IP tuple of the connection,–neighbor’s peer type(customer,provider or peer),–metric,or cost of the link–various timeout values(hold,retry,keepalive)HLPCore:The HLPCore contains the Lib,DecisionTable,ExceptionTable,and the AS-Prefix Map.It maintains the periodic update timer3,and interfaces between the user and the system.The core also connects Peers with the Lib and DecisionTable,so that incoming routing information can be processed and then pushed out of the system if necessary.Link-State Information Base(LIB):The Lib stores link-state information gathered from LSAs received.The network topology constructed is then used to determine the shortest path to each destination AS from every neighbor.DecisionTable:The DecisionTable chooses the winning route amongst the routes stored in the RibInTables for a particular destination prefix.The selection is based on the order of preferences given in Section4.3.Winning routes are stored in a trie,after which they are pushed to the neighboring routers based on the route type as specified in Section4.4.In general the DecisionTable deals with FPVs,whilst the Lib deals with LSAs.ExceptionTable:The ExceptionTable stores the exceptions raised locally,as well as those raised by other ASs within the same hierarchy(exceptions raised are not explicitly propagated to other hierarchies).Currently,only information with regards to exception1are disseminated via LSAs.The ExceptionTable is used when the DecisionTable is determining whether a particular winning route should be sent to a neighbor,and when the Lib is computing the shortest path to destination ASs taking into account exception1s raised.AS-Prefix Map:This object stores the mapping of ASs to the corresponding advertised prefixes.Since the core of HLP manages routes at the prefix level4,and route changes are disseminated at the AS level,the AS-Prefix Map is required to translate between the two.Thus,for instance,incoming route changes(which will not include the prefixes involved,but just the AS path)will be processed in the HLPCore at the prefix level,and merged again just before the updates are pushed out.7Finite State MachineThefinite state machine for each peering connection is the same as that specified in[2].8Protocol FormatThe message header format as specified in [2]remains unchanged,as is the format of the Keepalive packet.In this section we describe the changes to the Open and Update (renamed Fragmented Path-Vector)packets,as well as introduce the LSA packet.8.1Open PacketVersionMy AS numberHold timeHLP identifierPeer type12241Figure 7:Format of Open packet,numbers denote lengths of corresponding fields in octetsSince a HLP network is dependent on the relationship between neighboring ASs,it is important that they agree on that.We thus include an additional field in the Open packet,the peer type field.The relationship type inserted in the field is with respect to the neighbor.For instance,if AS A is a customer of B,it will insert type corresponding to customer in the field of the Open packet it sends to B.Inconsistencies will result in the connection failing.8.2Fragmented Path Vector PacketThe format of the FPV ,shown in Figure 8,is similar to BGP’s Update packet,but with an additional AS Down field.When an AS becomes unreachable for any reason,rather than withdrawing every route to that AS,we propagate just the AS number in this field.Unfeasible routes lengthWithdrawn routesAS down lengthASnumbersTotal path attribute lengthPath attributesNetwork layerreachability informationX X2X 2X 2Figure 8:Format of FPV packet,the numbers denote lengths of corresponding fields in octets.An X means that the field length is variable.The format in which a network prefix is represented is shown in Figure 9.This representation is used for the network layer reachability information (NLRI)and withdrawn routes in Figures 8and 10.Length1PrefixX Figure 9:Representation of a prefix:the Length field uses 1octet,and the size of the Prefix field is variable.8.3Link State Advertisement PacketThe LSA packet is a new packet type,and the fields are shown in Figure 10.We describe the four main fields and their corresponding subfields as follows:1.link changes :This major field contains information regarding links grouped together according to an endpoint AS’number.For instance,all links stated in “link information (1)”have an end AS with number “AS (1)number”.Thus,multiple link changes can be aggregated and transmitted within the same packet.The format in which information for each link is transmitted is shown in Figure 11.2.unreachable ASs :These fields provide the list of ASs (“Unreachable ASs”)that are declared unreachable from an AS (“AS unreachable from”).This field is used to disseminate an AS’setting of exception 1.lengthLink changesAS unreachable from (1)UnreachableAS length (1)UnreachableASs (1)Unreachable AS lengthReachable AS length AS reachablefrom (1)ReachableAS length (1)ReachableASs (1)AS reachablefrom (n)ReachableAS length (n)ReachableASs (n)Unfeasible routes length Withdrawn routesNLRI total length AS announcingNLRI (1)NLRIlength (1)AS (1)numberLink changeslength (1)Linkinformation (1)NLRI (1)AS announcingNLRI (n)NLRIlength (n)AS unreachablefrom (n)UnreachableAS length (n)UnreachableASs (n)AS (n)numberLink changeslength (n)Linkinformation (n)222 222X2222NLRI (n)2222X2X22X22XXX X22XFigure10:Format of LSA packet.The numbers representfield size in octets,X means thefield size is variable.Neighbor AS number NeighborrelationOperation Reserved Metric1622432Figure11:Link information representation format.The numbers representfield size in bits.3.reachable ASs:Thesefields provide the list of ASs(“Reachable ASs”)that are declared reachable from an AS(“ASreachable from”).Note that the list of ASs must have previously been declared unreachable.Thisfield is used when deleting exception1.4.unfeasible routes:Similar to Update packets,thisfield holds the routes that have been withdrawn by ASs in the samehierarchy.5.NLRI announcements:Thefinalfield gives the prefixes that each AS is announcing.9Boot Up ProcedureThe HLP protocol does not require knowledge of the tier level an AS is at.When connection to a new neighbor is established,the following steps are taken:if neighbor is a peersend all routes tagged with PEER_FPV and CUSTOMER_LSAif neighbor is a customersend all routes tagged with PEER_FPV and CUSTOMER_LSAsend all link-state informationsend all exception informationif neighbor is a providersend all link-state information for customer ASssend all exception informationAdditional routes that match exceptions,if any,are also sent.10Exception Setting and RemovalHLP allows dynamic setting and deletion of exceptions.Setting of exceptions should cause the network state to become the same as if the exceptions were present on bootup.Similarly,deletion of exceptions should cause the state to be the same as if the exceptions were never present.The following steps are taken when the corresponding exceptions are raised or removed:Exception1:Upon setting of exception1,the AS broadcasts an LSA packet in its hierarchy indicating the lack ofa customer route to the destination AS.It removes route(s)to the destination AS(tagged with CUSTOMERLSA and PROVIDER。
1-Introduction+(new)
Wine Types
• Sparkling wines (起泡酒)
德国
China
Portugal
中国
智利
Chile
Argentina
South Africa
Australia
阿根廷
南非
澳大利亚
NewZealand
新西兰
Old World
• Long-established traditional within European countries • History: thousands of years • France, Italy, German, Portugal & Spain
– has less contact with the grape skin – more body than white but, not as full as red – very seasonal drink, mostly in summer
Styles of Wine
• Sweetness
Styles of Wine
• Medium Bodied
– Feel richer and more substantial – Extra texture given from
• Grapes • Oak barrels
• White Burgundy from France • Merlot from Chile
高二英语选修6(外研版)课件3-1Introduction
知识拓展
1)常与trust搭配的短语有： have trust in 对„„信任 put no trust in 对„„不信任 fulfil one's trust 尽职尽责 2)辨析：trust, believe, believe in ①trust sb.指相信某人的品德、为人、能力等。 ②believe sb. 指相信某人说的话。
外 研 版 英 语
功能
语法
Module 3 Interpersonal Relationships-Friendship
外 研 版 英 语
Module 3 Interpersonal Relationships-Friendship
外 研 版 英 语
Module 3 Interpersonal Relationships-Friendship
外 研 版 英 语
①I can't trust her with my car.
＝I can't trust my car to her. 我不能托她保管我的车。
Module 3 Interpersonal Relationships-Friendship
②You might trust her to do the work.
外 研 版 英 语
She came close to him.
她走近他。
Module 3 Interpersonal Relationships-Friendship
词语辨析
close与closely 二者都可作副词用：close指位置上的接近；closely表 示抽象的“密切地，紧紧地”。 ①Move close, so I can see your eyes. 靠近些，那样我可以看见你的眼睛。 ②They are closely related. 他们关系密切。
高一英语必修3(外研版)课件1-1Introduction
知识拓展
within/out of range 在射程内/外(的) in the range of 在„„范围内；在射程内 out of the range of 在„„范围外；在射程外 range from A to B/between A and B 在A和B之间变化
外 研 版 英 语
Module 1 Europe
外 研 版 英 语
Байду номын сангаас
across from (美)在„„对过
It is across to you.(美口)这是你的事了。
Module 1 Europe
词语辨析
across, through, over 强调从某个平面的一边到另一 边。 through 指从某个立体空间内穿过。 over 侧重越过某种障碍物等。 across
外 研 版 英 语
A．across; across
C．over; into 答案：D
B．over; through
D．across; through
Module 1 Europe
3．face vt. 面对；面向；面临；vi.朝；向
①My house faces south.＝My house faces to the south. 我的房子朝南。 ②We must learn to face difficulties squarely and try to overcome them. 我们应该学会正视困难，并努力克服它们。
Module 1 Europe
外 研 版 英 语
Module 1 Europe
外 研 版 英 语
Module 1 Europe
类别 话题 课程标准要求掌握的项目 Some cities of Europe & how to describe location across, continental, range, face, gallery, architect, project, civilization, sign, situated, symbol, located, ancient, sculpture, opposite, agreement, whereabouts, govern, representative, geographical, feature, produce, parliament, region
Unit 1 Introduction
Unit 1 IntroductionⅠ、ReadingAn Introduction to the classHello, everyone. I am very glad to be here to introduce myself.大家好，我很高兴在这里介绍我自己。
My Chinese name is Chen Hua and my English name in Jack.I’m16 我中文名字叫陈华，英文名字叫杰克。
我今年16岁。
years old. My height is 1.70 meters and I’m neither fat nor thin. I come我身高1米7，我既不肥也不瘦，我来自梅州from Meizou and now I live in Guangzhou. There are three people in my 我现在住在广州，我家有三口——父母和我。
family__ my parents and I. My father is 46 years old and he’s a manager 我父亲46岁，是一家物流公司的经理。
in a logistics company. My mother is 42 years old and she’s a designer in 我妈妈说42岁，是一家广告公司的设计师a advertising company. I am a student in Guangzhou Technical School. 我是广州技校的一名学生。
Although my school is not large, it’s good and safe. It’s also clean and虽然我的学校不大，但很好且安全，干净又舒适comfortable. I like sports such as badminton and football. Football is my 我喜欢像羽毛球、足球这样的运动。
高二英语必修5(外研版)2-1Introduction
外 研 版 英 语
demand, traditional, suffer, double, individual,
答案：D
外 研 版 英 语
必修⑤
第一课时
Module 2
A job worth doing
2．intellectual 1)adj. 智力的，要用脑力的 The argument was too intellectual for me; I couldn't follow a word of it. 这场争论对我来说太深奥了，我一点儿都搞不明 白。 2)adj. 有很高智力的，理解力强的 an intellectual family 有知识的家庭
外 研 版 英 语
必修⑤
第一课时
Module 2
A job worth doing
2)worthwhile与worthy一样，既可作表语，又可作 定语。表示某事情重要、有趣或受益大而值得花时间、 金钱或努力去做，一般作“值得的”，“值得做的”， “有意义的”解。用作表语时，常构成It is worthwhile doing/to do...句式。 ①It is worthwhile to take up this job. 做这项工作很值得。 ②Nursing is a very worthwhile career. 护理工作是很值得干的职业。
答案：intellectual ability
外 研 版 英 语
必修⑤
第一课时
高一英语必修3(外研版)课件3-1Introduction
外 研 版 英 语
Module 3 The Violence of Nature
外 研 版 英 语
Module 3 The Violence of Nature
类别 课程标准要求掌握的项目
话题 Tornado, Hurricane, Earthquake and the Violence of Nature
外 研 版 英 语
你体验过真正的饥饿吗？
Module 3 The Violence of Nature
知识拓展
inexperience n. 不成熟 inexpert adj. 拙劣的 inexperienced adj. 不熟练的；经验不足的 be experienced in 在„„方面老练 expert n. & adj. 专家；熟练的
即学即用
Many people say________is shown on TV. A．too much violence B．much too violence C．too many violences D．quite a few violences 答案：A
外 研 版 英 语
Module 3 The Violence of Nature
外 研 版 英 语
Module 3 The Violence of Nature
2)n. [C]经历
①Please tell us your experiences while in Africa. 请告诉我们你在非洲的经历。 ②Reaching the top of Mount Tai was an unforgettable experience. 登上泰山极顶是一次难忘的经历。 3)v. 经历；体验 Have you ever experienced real hunger?
高二英语必修5(外研版)5-1Introduction
2)检查(是否有误)；搜索；搜查
必修⑤
第一课时
Module 5
The Great Sports Personality
①The mechanic went over the engine but found nothing wrong. 机修工检查了发动机，但没有发现什么毛病。 ②The police went over his room three times, but found nothing. 警察把他的房间搜查了三遍，但什么也没有找到。 ③重复；温习 The actor had to go over his lines many times before he got them right. 这位演员要把台词重复好多遍才能记正确。
必修⑤ 第一课时
外 研 版 英 语
Module 5
The Great Sports Personality
助记 归类 net 种种：
外 研 版 英 语
必修⑤
第一课时
Module 5
The Great Sports Personality
搭配 be caught in the net of 陷入„„的困境 cast/throw a net 撒网 draw in a net 拉网，收网
Module 5
The Great Sports Personality
3．athletics n. [U]田径运动(教材 P41) ①I like all the athletics events. 我喜欢所有的田径项目。 ②Runners in an athletics stadium run in individual lanes. 在田径运动场上赛跑的人有各自的跑道。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
• 第二单元－ IP协议
• 第三单元－网络交换 • 第四单元－网络服务 质量控制
• 第七单元－ VPN
• 第八单元－ 组播技术
• 第九单元－ 移动IP技术
• 第十单元－ 网络管理
5
参考书目
徐恪等编著，高级计算机网络，清华大学出版社，2012年 10月； 徐恪等编著，计算机网络体系结构，清华大学出版社， 2014年2月； John Day，Patterns in Network Architecture – A Return to Fundamentals，Prentice Hall， 2008； Douglas E. Comer著，用TCP/IP进行网际互连，第一卷：原理、 协议和体系结构，清华大学出版社，1998年9月；
• 车载网VANET
• 家庭网 Home Networking
• 物联网 IoT
• 容迟网DTN
• 监控与数据采集系统 SCADA (Supervisory Control and Data Acquisition)
16
网络体系结构概论
• 计算机网络的结构 • 网络体系结构模型 • 网络技术体系
• 影响网络体系结构的主要因素
– Coherent architecture captures and institutionalizes strong, tested design principles
19
A Brief History
• 从操作系统到独立的网络软件
– ARPANET的NCP是单体的协议软件 – 主机与网络的分离（法国的CYCLADES） – 串珠结构 beads on a string
1
课程目的
• 从网络体系结构的角度理解网络技术及 其相互关系；
• 系统地掌握计算机网络互联的基本概念 和方法，了解互联网及其发展趋势； • 培养计算机网络系统的规划设计能力。
2
为什么以互联网为背景
• 互联网是各种网络技术的主要背景
– 异构的网络
• 互联是各类网络问题的主要来源
– 分治的网络
• 互联是网络体系结构发展的基本动力
不仅有原则，还有设计
– Structuring principles – Functional decomposition and system modularity
18
网络体系结构设计的基本要求
• 通用性
– Coherent architecture helps general-purpose systems stay that way
• 影响网络体系结构的主要因素
7
电话网的基本结构
长途服务 本地服务
LATAs
LEC
IXC的POP
pop
Toll Office
干线/ 信令
用户
用户
交换局
用户环路
Local Loop
交换局
EO
用户
Local Access and Transport Area
POP: Point of Present IXC: Inter-exchange center LEC: Local exchange center
14
网络的分类－管理模式
• 互联网
–由若干独立的计算机网络互连而成的，往往存在 层次结构；
–采用分域自治管理方式，管理策略为博弈关系；
–异构的物理网络技术，统一的逻辑网络体系结构；
–各个互联的网络在逻辑结构上分离，但拓扑结构 可能重叠。
15
网络的分类－应用领域
• 移动自组网 MANETFra bibliotek• 传感网 WSN
计算机网络体系结构
东南大学 计算机科学与工程学院 软件学院
龚俭 曹争
{jgong,zcao}@
ftp://202.112.23.163:2121/ Bras ftp://211.65.193.27:2121/ 10/8 ftp://[2001:da8:1001:7::44]:2121/ ftp://:2121/
• 城域网（Metropolitan Area Network）
– 大范围 (100+公里) 的LAN， 不使用竞争性媒体传输控制机 制。
• 局域网（Local Area Network）
– 一种小范围的计算机网络，用 在建筑物内、校园内等几公里 范围之内的计算机连网。 – 采用广播信道技术，有方向或 无方向； – 具有固定的拓扑结构：总线形 或环形。
27
网络体系结构概论
• 计算机网络的结构 • 网络体系结构模型 • 网络技术体系
• 影响网络体系结构的主要因素
28
Bit Stream
• 数据传输技术
–解决在不同媒体上进行数据传输所遇到的各种问 题； –研究的内容：信息理论，数据编码技术，调制解 调技术，复用技术，传输协议（数据接口）
•
主干网 是传送信息的主体网络，是除接入网和用户住 地网之外的全部网。
11
网络的分类-功能作用
• 刻划信息网络中功能的分类及其相互关系 • 承载网 是各种形式通信媒体和各种通信方式的集合， 它向业务网提供实现这些业务所需的传输和连接能 力；(DDN、SDH、OTN、ASON) • 业务网 基于传送网之上提供各种不含特定目的的信 息服务，可分为基本业务、增值业务、和扩展业务； (Leased line、VPN、VoIP、IPTV etc.) • 支撑网 是传送网和业务网所需的一些专用辅助性 网络的总称。（网管系统、信令通道、手机漫游计费）
Bassam Halabi著，彭业飞等译，因特网的路由选择技术 － 因 特 网 路 由 选 择 方 案 与 实 例 （ Internet Routing Architectures），电子工业出版社，1998年4月； ：查找有关的RFC
6
网络体系结构概论
• 计算机网络的结构 • 网络体系结构模型 • 网络技术体系
23
OSI的层次模型
应用层 表示层
为用户提供到OSI环境的接入，以及 提供分布式信息服务 提供从不同的数据表示（语法）到应用进 程的独立性 提供在应用程序之间通信的控制结构；在 协同工作的应用程序之间建立、管理和释 放连接 提供在端点之间可靠、透明地传送数据； 提供端到端的差错恢复和流量控制 使高层与数据传输和用来连接系统的交换 技术无关；负责建立、维持和释放连接 使通过物理链路的信息传送变得可靠；发 送带有必要的同步、差错控制和流量控制 关心在物理媒体上非结构化的比特流的传 的数据块（帧） 输；考虑接入物理媒体所涉及机械的、电 气的、功能的和过程的特性 存在总体框架，用严格的层次关系来表述网络功能的划分及其之间的关系； 平等的协议实体，抽象的层间接口与交互数据结构。
– 膨胀的网络
• 互联考虑是网络设计的核心
3
课程要求
• 学习要求
– – – – 课后复习，及时提问； 深入思考，补充细节； 广泛阅读，印证理解； 理顺思路，建立体系。
• 考核方式
– 报告：20％ – （开卷）考试：80％
4
课程的主要内容
• 第一单元－网络体系 结构的基本概念 • 第五单元－ IGP • 第六单元－ BGP
12
网络的分类－管理模式
• 公用网
–向公众提供商业化计算机网络服务的计算机网；
–网络传输系统和网络端系统的管理是分离的；
–网络应用系统是互不相关的，没有统一的管理；
–网络用户之间一般不相关，因此不使用统一的网 络管理和网络安全策略。
13
网络的分类－管理模式
• 专用网
–为特定的组织机构或行业所使用的计算机网络， 若传输信道基于公用网，则称为虚拟专用网； –一般使用统一的网络体系结构，和一致的管理策 略； –具备独立完整的网络管理系统，安全性较好； –具有封闭的应用系统和用户群。
• 协议与服务的分布
• 协议和网络服务的实现架构 • 例如：在哪里实现拥塞控制功能？ • SDN不是新的网络体系结构
26
Internet的体系结构
• 需要互联许多已经存在的 网络 • 对应用透明以支持网络技 术的可进化性 • 设计原则
– 网络仅支持最小功能集 （细腰） – 无先决条件 vs. 无保证
• 可进化性
– Coherent architecture allows different components of complex systems to evolve, at different rates, as technology and understanding changes
• 可遵从性
以网络服务的功能需要决定协议的存在性，协议在体系结构中的位置由其对体 系结构中其它协议的功能和数据结构依赖性决定，因此基于功能模型的体系结 构以核心协议为基础，无总体框架，其中各个协议之间无严格的层次界线。
25
网络的实现模型
• 协议与功能的选择
• 每个具体的网络都存在特定的网络体系结构，它通常是 某一标准体系结构的子集，确定了这个网络的功能结构 和功能之间的关系。 • 例如：是否需要拥塞控制？
24
会话层 运输层 网络层 数据链路层 物理层
TCP/IP的功能模型
HTML RT Data
SMTP POP, IMAP
FTP TCP IP
HTTP
DNS
RTP UDP
Signalling Protocols (e.g. ISUP)
SCTP OSPF BGP
ICMP ARP
RIP
SLIP
PPP
LAN-protocols, ATM, PSTN/ISDN, PLMN …
– 路由器中配置的IP地址 前缀覆盖的范围
• 网络节点Site
– 网络中的抽象节点 – 连续的物理子网覆盖 的范围