Communicating Digital Content

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1 計算機概論學習目標探索資訊科技 2016 探討要能夠成功進行通訊需要具備的要素, 並說明各種不同的傳送裝置和接收裝置分辨 LN MN WN 和 PN 的差異分辨主從式和對等式網路的差異第九章傳遞數位內容 hien-hua Tsai epartment of ccounting Information hihlee University of Technology 說明各種網路通訊標準和解釋通訊軟體的目的協定 Note: Some slides and/or pictures in the following are adapted from slides 2016 陳玄玲. p.331 hapter 9 2 學習目標通訊描述各種類型的通訊線路說明常用的通訊裝置探討架設和配置家庭網路的各種方式數位通訊是指在兩台或更多台電腦或裝置之間傳輸資料指令和資訊的過程分辨各種實體傳輸媒體分辨各種無線傳輸媒體傳送裝置傳輸媒體接收裝置 Note: Some slides and/or pictures in the following are adapted from slides 2016 陳玄玲. p.331 hapter 9 3 p.334 hapter 9 4 1

2 通訊網路網路 (network) 是一群透過通訊裝置和傳輸媒體, 連線在一起的電腦與裝置的集合使用網路的好處包括 : 促進通訊共用硬體共用資料和資訊共用軟體資金移轉 p.335 圖 10-1 hapter 9 5 p.334 hapter 9 6 網路網路區域網路 (local area network,ln) 是指連接有限地理區域內的多台電腦和裝置的網路 p.336 圖 10-2 hapter 9 7 p. 337 圖 hapter 9 8 2

3 網路網路無線區域網路 (wireless LN,WLN) 則是沒有實體纜線的 LN p.337 圖 hapter 9 9 都會網路 (metropolitan area network,mn) 是連接都會區內多個 LN 的高速網路廣域網路 (wide area network,wn) 是一種涵蓋廣大地理區域的網路個人區域網路 (personal area network,pn) 是使用有線或無線技術將個人工作空間內的電腦和裝置連接的網路 p.338 圖 10-5 hapter 9 10 網路 Networks 網路中電腦裝置和傳輸媒體的配置, 有時被稱為網路架構主從式網路 lient/server network 對等式網路 Peer-to-peer (P2P) network network topology refers to the layout of the computers and devices in a communications network Star network us network Ring network p.336 圖 hapter 9 11 hapter 9 3

通訊軟體網路通訊標準和協定通訊軟體 (communications software) 由下面幾種程式和 app 組成 : thernet Token ring 幫助使用者與其他電腦行動裝置或網路建立連線管理資料指令和資訊的傳輸 TP/IP luetooth Wi-i UW 提供介面供使用者彼此通訊 Ir N RI LT

341 hapter 9 14 網路通訊標準和協定網路通訊標準和協定 thernet( 乙太網路 ) 是一種網路標準, 它並未指定任何在網路 ( 或節點 ) 上負責控制何時傳輸資料的中央電腦或裝置記號環 (token ring) 標準中制訂網路上的電腦和裝置, 以單方向及預先設定的順序共用或傳遞特殊信號 ( 權杖記號 )

4 通訊軟體網路通訊標準和協定通訊軟體 (communications software) 由下面幾種程式和 app 組成 : thernet Token ring 幫助使用者與其他電腦行動裝置或網路建立連線管理資料指令和資訊的傳輸 TP/IP luetooth Wi-i UW 提供介面供使用者彼此通訊 Ir N RI LT p.341 hapter 9 13 p.341 hapter 9 14 網路通訊標準和協定網路通訊標準和協定 thernet( 乙太網路 ) 是一種網路標準, 它並未指定任何在網路 ( 或節點 ) 上負責控制何時傳輸資料的中央電腦或裝置記號環 (token ring) 標準中制訂網路上的電腦和裝置, 以單方向及預先設定的順序共用或傳遞特殊信號 ( 權杖記號 ) TP/IP 是一種網路協定, 定義訊息 ( 資料 ) 如何從網路一端繞送到另一端 Two approaches (standards) OSI reference model TP/IP protocol suite p.343 What's the difference between the terms protocol and standard? Protocols are like languages. (nglish language) Standards are like dictionaries. (Rules of nglish) hapter 9 15 p.344 圖 10-8 hapter

網路通訊標準和協定網路通訊標準和協定 Wi-i 是指任何以 802.11 標準為基礎的網路 802.

定義如何利用短距離無線電波在兩個藍牙裝置之間傳輸資料 UW (ultra-wideband) 是一種指定兩個 UW 裝置如何使用短距離無線電波以高速相互通訊的網路標準 Ir 透過紅外線 (infrared,ir)

5 網路通訊標準和協定網路通訊標準和協定 Wi-i 是指任何以標準為基礎的網路網路標準制訂兩個無線裝置如何透過空氣彼此通訊 LT (Long Term volution) 是一種網路標準, 它定義高速蜂巢式傳輸如何使用廣播無線電波, 傳輸行動通訊的資料藍牙 (luetooth) 是一種網路協定, 定義如何利用短距離無線電波在兩個藍牙裝置之間傳輸資料 UW (ultra-wideband) 是一種指定兩個 UW 裝置如何使用短距離無線電波以高速相互通訊的網路標準 Ir 透過紅外線 (infrared,ir) 光波以無線方式傳輸資料 RI (radio frequency identification, 無線射頻辨識 ) 是一種協定, 它定義網路如何使用無線電訊號, 與放置或附掛在物體動物或人類的某個標籤進行通訊 p hapter 9 17 p.348 圖 10-9 hapter 9 18 網路通訊標準和協定 Near-ield ommunication (N) N (near field communication, 近場通訊 ) 是一種以 RI 為基礎的通訊協定, 它定義兩個具有 N 技術的裝置或物件之間的網路, 如何使用近距離無線電波讓兩者通訊 p.348 圖 hapter 9 19 ticket stamping machine of the ustrian ederal Railways that can be used to purchase mobile tickets ("Handy-Ticket"). 20 5

6 Wireless Standards 通訊線路專線有線電視線路 SL ISN TTP T 載波線路 TM 21 p.349 hapter 9 22 通訊線路通訊線路 SL 是一種接收資料比傳送資料的傳輸速率較快的 SL p.349 表 10-2 hapter 9 23 p.350 圖 hapter

無線存取點 (wireless access point) 是一種中央通訊裝置,

7 通訊裝置通訊裝置通訊裝置 (communications device) 是指能夠在傳送裝置與接收裝置之間, 傳輸資料指令和資訊的任何類型硬體寬頻數據機將資料與資訊傳送到數位線路, 或從數位線路接收資料與資訊纜線數據機 SL 數據機 p.351 hapter 9 25 p.351 圖 10- hapter 9 26 通訊裝置通訊裝置無線數據機使用行動電話業者的網路, 以無線方式從電腦或行動裝置連接網際網路無線存取點 (wireless access point) 是一種中央通訊裝置, 能讓電腦和裝置以無線方式彼此間傳輸資料 p.352 圖 hapter 9 27 p.352 圖 hapter

protected by a hardware firewall 有些路由器提供額外的功能

8 通訊裝置通訊裝置路由器 (router) 是一種通訊裝置, 用來將多台電腦或與其他路由器連接起來, 並傳輸資料到網路上正確的目的地 Many are protected by a hardware firewall 有些路由器提供額外的功能 : 無線路由器寬頻路由器寬頻無線路由器行動寬頻無線路由器 p.354 圖 hapter 9 29 p.355 圖 hapter 9 30 通訊裝置通訊裝置網路卡 (network card) 能讓沒有內建網路功能的電腦或裝置能存取網路網路卡的形式有很多種集線器 (hub) 或交換器 (switch) 是提供網路中所有纜線一個集中點的裝置 p.355 圖 hapter 9 31 p.356 圖 hapter

9 家庭網路傳輸媒體許多家庭使用者將多台電腦和裝置連線在一起形成家庭網路 (home network) 傳輸媒體 (transmission media) 能夠承載一或多個通訊訊號寬頻 (broadband) 媒體同時可傳輸多個訊號在傳輸媒體上流通的資料指令和資訊數量, 有時稱為頻寬 (bandwidth) 延遲 (latency) 是指訊號從一個位置傳到網路上另一個位置所花的時間 p.357 hapter 9 33 p 圖 hapter 9 34 實體傳輸媒體實體傳輸媒體 Twisted-pair cable iber-optic cable oaxial cable p.360 表 10-3 hapter 9 35 p 圖 hapter

10 無線傳輸媒體無線傳輸媒體廣播無線電 (broadcast radio) 是一種透過空氣長距離傳播無線電訊號的無線傳輸媒體蜂巢式無線電 (cellular radio) 是一種廣泛用於行動通訊的廣播無線電形式 p.362 表 10-4 hapter 9 37 p.363 圖 hapter 9 38 無線傳輸媒體無線傳輸媒體微波 (microwave) 是可提供高速訊號傳輸的無線電波通訊衛星 (communications satellite) 是一種太空站, 可接收來自地面站台的微波訊號, 並放大 ( 加強 ) 訊號, 然後將訊號透過寬闊區域廣播回任何數量的地面站台 p.365 圖 hapter 9 39 p 圖 hapter

367 圖 10-26 hapter 9 42 重點摘要 Reading ssignment 網路與通訊技術各種類型的網路架構標準和協定

11 無線傳輸媒體無線傳輸媒體 GPS (global positioning system, 全球定位系統 ) 是由一或多個可接收並分析從衛星傳送而來的訊號, 找出接收器地理位置的地面接收器組成的導航系統 p.366 hapter 9 41 p.367 圖 hapter 9 42 重點摘要 Reading ssignment 網路與通訊技術各種類型的網路架構標準和協定通訊軟體 hapter 9 of 計算機概論探索資訊科技 2016, 陳玄玲. 通訊線路和通訊裝置如何架設家庭網路實體傳輸媒體和無線傳輸媒體 p.368 hapter 9 43 hapter

OSI Reference Model OSI Reference Model 45 1. Physical Transmits a bit stream over a physical medium.

Network Source to destination delivery of a packet. 4.

Session stablishes, maintains, and synchronizes the dialog between communicating systems, at the unit

12 OSI Reference Model OSI Reference Model Physical Transmits a bit stream over a physical medium. 2. ata Link Organizes bits into logical units called frames. Node to node delivery 3. Network Source to destination delivery of a packet. 4. Transport Source to destination delivery of the entire segment. 5. Session stablishes, maintains, and synchronizes the dialog between communicating systems, at the unit of messages. 6. Presentation eals with the fact that different systems use different coding methods. 7. pplication nables the user to access the network. 46 OSI Reference Model OSI Reference Model 47 48

13 TP/IP Protocol Stack (Internet Model) omparing TP/IP with OSI The TP/IP reference model and the TP/IP protocol stack make data communication possible between any two computers, anywhere in the world. Pretty similar to OSI TP/IP has less layers (four) Main difference in layers is after layer Mapping the Internet to OSI Mapping the Internet to OSI

The Importance of TP/IP Internet Protocol (IP) Higher Level Protocols (Not TP/IP s oncern!

) IP is the network layer Unreliable service connectionless datagram protocol est effort delivery No

delivered out-of-order Packets may be lost or arbitrarily delayed Successive packets may not follow the

53 54 IP Packet Structure Transmission ontrol Protocol (TP) yte-stream socket abstraction for

14 The Importance of TP/IP Internet Protocol (IP) Higher Level Protocols (Not TP/IP s oncern!) SMTP Telnet SNMP TP HTTP GP Lower Level Protocols (Not TP/IP s oncern!) IP is the network layer Unreliable service connectionless datagram protocol est effort delivery No error detection or correction for packet data No network congestion control (beyond drop ) Packets can be delivered out-of-order Packets may be lost or arbitrarily delayed Successive packets may not follow the same path Two versions of the IP are in use: IP Version 4 and IP Version IP Packet Structure Transmission ontrol Protocol (TP) yte-stream socket abstraction for applications Retransmission of lost or corrupted packets low-control to respond to network congestion Simultaneous transmission in both directions Multiplexing of multiple logical connections

TP Segment ormat TP ommunication lags 57 Synchronize alias SYN : Initiates connection between hosts cknowledgement alias K : stablishes connection between hosts Push

ommunicates to the remote system of no more retransmissions Reset alias RST : Resets a connection 58 The TP Three-Way Handshake onnection stablishment The TP Three-Way

15 TP Segment ormat TP ommunication lags 57 Synchronize alias SYN : Initiates connection between hosts cknowledgement alias K : stablishes connection between hosts Push alias PSH : System accepting requests and forwarding buffered data Urgent alias URG : Instructs data contained in packets to be processed SP inish alias IN : ommunicates to the remote system of no more retransmissions Reset alias RST : Resets a connection 58 The TP Three-Way Handshake onnection stablishment The TP Three-Way Handshake stablishes a connection. 1. : I would like to talk to you. sends a SYN packet to 2. : Ok, let's talk. sends a SYN+K packet to 3. : Thanks for agreeing. sends K to

16 The TP Three-Way Handshake The TP Three-Way Handshake onnection Termination Your Turn: TP Three-Way Handshake User atagram Protocol (UP) lags Src st Seq # ck # nswer Some applications do not want or need TP on t need recovery from lost or corrupted packets on t want flow control to respond to loss/congestion mount of UP packets is rapidly increasing ommonly used for multimedia applications UP traffic interferes with TP performance ut, many firewalls do not accept UP packets ealing with the growth in UP traffic Pressure for applications to apply flow control uture routers may enforce TP-like behavior Need better mathematical models of TP behavior

User atagram Protocol (UP) UP Segment ormat Unreliable service No flow and error control 65 66 TP vs.

17 User atagram Protocol (UP) UP Segment ormat Unreliable service No flow and error control TP vs. UP Popular Ports and Services TP onnection-oriented Three Way Handshake Reliability more important than Speed UP onnectionless No Handshake Speed more important than Reliability 20/21 TP TP 23 TLNT TP 25 SMTP TP 53 NS UP TP 80 HTTP TP 110 POP3 TP 161 SNMP UP HTTPS TP 68 17

Routing in the Internet Routing in the Internet The Global Internet consists of domains interconnected with each other domain is also called an utonomous Systems (S) n S is identified

, hihlee SN is 1659 ach S chooses its own routing protocol inside its S Such protocols are called Interior Gateway Protocols (IGP) Routers in different S's can run different intra-s

18 Routing in the Internet Routing in the Internet The Global Internet consists of domains interconnected with each other domain is also called an utonomous Systems (S) n S is identified by an S Number (SN), e.g., hihlee SN is 1659 ach S chooses its own routing protocol inside its S Such protocols are called Interior Gateway Protocols (IGP) Routers in different S's can run different intra-s routing protocols (e.g., RIP, OSP) single inter-s (interdomain) routing protocol in the current Internet: order Gateway Protocol (GP) protocol runs among S s is called an xterior Gateway Protocol (GP) 69 Popular routing protocols 70 Routing in the Internet Routing in the Internet n autonomous system (S) is a group of networks and routers under the authority of a single administration. gateway routers of same S share learned external routes using igp. Gateway routers participate in intradomain to learn internal routes. Intradomain routing Interdomain routing S (RIP intra routing) a b egp S (OSP intra routing) e igp S (OSP intra routing) i 71 Gateway routers of diff. S s exchange routes using egp d c f g h 72 18

19 Open Shortest-Path irst (OSP) Routing uilding OSP Routing Table Network is a graph with routers and links ach unidirectional link has a weight Shortest-path routes from sum of link weights Weights are assigned statically (configuration file) Weights based on capacity, distance, and traffic looding of info about weights and IP addresses (0) link router Graph: G = (N,) N = set of routers = { u, v, w, x, y, z } u v x w y z = set of links ={ (u,v), (u,x), (v,x), (v,w), (x,w), (x,y), (w,y), (w,z), (y,z) } uilding OSP Routing Table uilding OSP Routing Table (0) (0) (8) (20) (8) (20) (25)

20 uilding OSP Routing Table uilding OSP Routing Table (0) (0) (8) (20) (8) (20) 17 (25) (30) 17 (25) (30) (44) (42) uilding OSP Routing Table uilding OSP Routing Table (0) (0) (8) (20) (8) (20) 17 (25) (30) 17 (25) (30) (44) (42) (44) (42)

21 uilding OSP Routing Table uilding OSP Routing Table (8) (0) (30) (44) (20) 81 (8) (0) (30) (44) (20) The shortest path tree of router orwarding table estination Metric Next hop Your Turn: uilding Routing Table Your Turn: uilding Routing Table orwarding table estination Metric Next hop heck the case! The shortest path tree of router

22 Whois Lookup Service 計算機概論探索資訊科技 2016 第九章傳遞數位內容 85 hapter 9 omplete 22

Microsoft PowerPoint - 数据通信-ch1.ppt

Microsoft PowerPoint - 数据通信-ch1.ppt 主要内容与基本要求主要内容数据通信与计算机网络计算机网络的发展过程分类以及主要性能指标 ; 分组交换的基本原理及其与电路交换报文交换的联系与区别 ; 计算机网络的协议与体系结构第 1 章概述基本要求掌握分组交换电路