1. 广西医科大学
Computer Networking
网络课件
双语教学
模拟实验
计算机网络教研室

2. Network Classification
CHAPTER 2
Network Classification DI 1
The first section 2
Exercises 3
Online lecture

3. Chapter 2 Network Classification
2.1 Introduction
Many ways that networks can be classified 1 2
Distinguish among WAN,MAN,and LAN
Describe voice network 3
classification [,klæsifi`keiʃən]n.分类, 分级 distinguish [dis`tiŋɡwiʃ]vt. & vi.辨别, 区别
describe [dis`kraib]vt.描写, 叙述
Explain the concept of internetworking 4
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

4. Chapter 2 Network Classification
2.2 definition of network
A communications network is an interconnected system of computers, terminals, and other hardware established for the purpose of exchanging information or services between individuals, groups, or institutions.
definition [,defi`niʃən]n.定义, 释义 formal [`fɔ:məl]adj.正式的， communication [kə,mju:ni`keiʃən]n.交流
通信网络为个人、组织或机构之间的信息或服务交换，将计算机、终端或其他硬件设备互连而成的系统。
medium
DATA 资源 PC

5. Chapter 2 Network Classification
NODE
A node on a network is a point of connection into a network, or a point at which one or more transmission lines (circuits) interconnect, such as where a router or a switch connects into the network.
网络中的节点即接入网络的一个连接点，或者一条或多条传输线路互连的交叉点。
node [nəud]n.节
five node network

6. Nodes are points of entry into a network or interconnection within in
Chapter 2 Network Classification
Nodes are points of entry into a network or interconnection within in
节点是网络的入口或网络内部的互连交叉点。
five node network
For example
computer terminal
modem, hub, bridge or switch
Print Scanner

7. Chapter 2 Network Classification
NETWORKS CLASSIFIED B F C D A
Geography
Topology
Ownership
Transmission Mode
Other types of networks
Geographydʒi`ɔɡrəfi]n.地理(学), topology [tə`pɔlədʒi]n.拓扑 ownership [`əunəʃip]n.所有权 transmission [trænz`miʃən]n.传送, 传播
configuration [kən,fiɡju`reiʃən]n.构造
Internetworks E
Topology Ownership Other types of networks Line Configuration Transmission Mode Internetworks

8. 2-3 NETWORKS CLASSIFIED BY GEOGRAPHY
Chapter 2 Network Classification
2.3.1 LAN (Local Area Networks)
Networks that cover a small geographic area are called LANs.
2-3 NETWORKS CLASSIFIED BY GEOGRAPHY
集线器/交换机
LAN network could be installed in a home.
LAN is useful for sharing resources like files, printers, games or other applications.
local [`ləukəl]adj. 当地的, 局部的 area [ˈɛəriə]n.面积 LAN [læn]

9. Chapter 2 Network Classification
Key attribute of LAN
Its limited geographic scope. Don`t care the number of nodes. much higher data-transfer rates . LANs are frequently found in business offices. And lack of a need for leased telecommunication lines.
attribute [ə`tribju:t] 属性vt. scope [skəup]n.范围 frequent [`fri:kwənt]常见的 lack [læk]vt.缺乏 lease [li:s]vt.租
telecommunication [`telikə,mjuni-`keiʃən]n.电信

10. Metropolitan Area Networks (MANs)
Chapter 2 Network Classification
Metropolitan Area Networks (MANs)
MAN covers an intermediate area, such as a city and usually links several LANS. MAN standard :IEEE IEEE: Institute of Electrical and Electronics Engineers, Inc
metropolitan [,metrə`pɔlitən]adj.大都会的, 大城市的 MAN [mæn]
IEEE 电子电气工程师协会
城域网技术由IEEE委员会标准化。

11. MANs normally operate at high speed.
Chapter 2 Network Classification
MANs normally operate at high speed.
MANs normally operate at high speed. Not medium
城域网通常连接高速运行的局域网，因此常需要在城域网的不同位置之间提供高速度。
Figure A MAN.

12. Chapter 2 Network Classification
Dark fiber:
It is optical fiber that has been installed (typically in the ground) but which does not have the necessary electronics installed at each end to make it usable.
fiber [`faibə]n. cable [`keibl]n.电缆 optic[`ɔptik]adj.光学的 manufactured [,mænju`fæktʃəd]adj.人造的
光纤术语暗光纤指被涂成黑色以提高反射能力的光纤。错误
unused fiber-optic cable. Often times companies lay more lines than what's needed .its can be leased to individuals or other companies who want to establish optical connections among their own locations.
*The term dark fiber refers to fiber that has been manufactured with black pigment to improve its reflectivity.F

13. Chapter 2 Network Classification
DQDB:Distributed Queue Dual Bus
IEEE 802.6，Cancelled
A MAN technology early.
have not been large-scale application.
distributed [dis`tribju:tid]adj.分布式的 dual [`dju:əl]adj.两部分的, cancel [`kænsəl]vt.取消, 废除
(分布式队列双总线)
目前，该技术已取消。没有大规模应用。
双总线、分布式排队
有两条单向总线，两条总线通信方向相反
节点使用双总线可全双工通信
总线上的节点形成分布式队列
DQDB Buses and Nodes

14. Chapter 2 Network Classification
Fiber IP MAN
WDM FIBER
光纤IP城域网
由于光纤技术的发展，城域骨干组网技术普遍采用单模光纤，一则传输距离远，二则波分复用技术（WDM）的要求。

15. CAN (Campus Area Network )
Chapter 2 Network Classification
CAN (Campus Area Network )
A network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus.
campus [`kæmpəs]n.(大学)校园 spanning [`spæniŋ]adj.跨越

16. Wide Area Networks(WANs)
Chapter 2 Network Classification
Wide Area Networks(WANs)
Networks that cover a broad geographic area are called WANs. WANs usually crosses public rights of way. The Internet is the largest WAN, spanning横跨 the Earth.
broad [brɔ:d]adj.宽的, 阔的 WAN [wən]碗,大碗
通常穿越公共路权。

17. The world's largest WAN is the Internet.
Chapter 2 Network Classification
The world's largest WAN is the Internet.
provided [prə`vaidid]提供 carrier [`kæriə]n.搬运人; 送信人; 带菌者
世界最大的WAN是Internet.
广域网常常使用一个或多个通信运营商提供电路。
WAN usually uses circuits provided by one or more communication carriers.
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

18. Why do WANs not operate at as high speed as LANs do ?
Chapter 2 Network Classification
Why do WANs not operate at as high speed as LANs do ?
The communication circuits that make up A WAN exist in a much harsher environment Than those of a LAN. more likely to experience errors. Expensive leased lines .
harsh [hɑ:ʃ]adj. 严酷的 environment [in`vaiərənmənt]n.环境, experience [iks`piəriəns]n.经历 expensive [iks`pensiv]adj.昂贵的
error [`erə].错误

19. 2.4 NETWORKS CLASSIFIED BY TOPOLOGY
Chapter 2 Network Classification
2.4 NETWORKS CLASSIFIED BY TOPOLOGY
Network Topology : The configuration of a communication network-the way the circuits are connected together.
topology [tə`pɔlədʒi]n.拓扑,
通信网络的配置称为网络拓扑，即通信线路互相连接的方式。
primary [`praiməri]adj.首要的 purpose [`pə:pəs]n.目的 indicate [`indikeit]vt.标示
*The primary purpose of the network topology isn't to indicate the technology used by the network.

20. Chapter 2 Network Classification
2.4.1 Star network
All circuits radiate from a central node, which is often a cluster of servers or a host computer. It is still often used for voice network.
radiate [`reidieit]vt.发射出(光、热等) cluster [`klʌstə]n.从中心，集中 host computer.主机 host [həust]n.东道主, 主人
星型网络来源于电话，还用在语音网络。
Star networks can have a maximum of six arms F

21. Advance and Disadvance
Chapter 2 Network Classification
Advance and Disadvance
ease to manage and control network.
Protocol was relatively simple.
Star configuration was easy to implement.
If central node is down, network is out of service.
In times of peak traffic, Central node may become overloaded.
protocol [`prəutəkɔl]n.协议 relatively [`relətivli]adv.相关地

22. Chapter 2 Network Classification
2.4.2 Hierarchical network
A network in which the top node in the structure is called the root node is called a hierarchical network. It has a tree structure. At least three levels in the hierarchy .WHY? Two levels= equality
tree
hierarchical [,haiə`rɑ:kikəl]adj.分等级的 分层的 层次型网络。
网络结构中的顶部节点被称为根节点的网络是层次型网络。
equality [i:`kwɔliti]n.同等,

23. Figure 2-4 A hierarchical network.
Chapter 2 Network Classification
It can be compared to a corporate organization chart.
compare to compare [kəm`pɛə]vt. & vi.
比较, 对照 把…比作, 喻为
比喻为一个典型的公司组织图。
根接点看作组织图的公司总部，下面中间节点看作各部门机构。
Figure A hierarchical network.

24. Chapter 2 Network Classification
Advantages
No single point of failure in the network
If one division's network fails, the other division are not affected.
failure [`feiljə]n.失败 extend [iks`tend]vt. & vi.延伸; 延续vt.延长; 扩展;
Easy to extend

25. Chapter 2 Network Classification
2.4.3Mesh network
It is similar to a hierarchical network, except that there are more interconnections between nodes at different levels-or even at the same level. ADVS: provides redundant connection. No single point of failure that cause entire network to fail. WAN and PSTN are configured in a mesh topology .
网格形拓扑
mesh [meʃ]n.网状, level [`levl]n.水平线 fail [feil]vt. & vi.在…中失败
除不同层次接点或同一层次接点之间有更多互连外,该网络与层次型网络很相似.
提供冗余连接，并没有单点错误而造成整个网络瘫痪。

26. Chapter 2 Network Classification
In a partially interconnected mesh network
Fully interconnected mesh network.
partially [`pɑ:ʃəli]adv.部分地 major [`meidʒə]adj.较大的;
由于开销的原因，这种全连接网络很少实现。主要节点要相互连接，相对次要节点则与某一个或几个地点连接。
部分互联的网状网络中，每个节点不是连接到其他所有节点。
为什么很少建立全连接网状网络？
each node isn`t connected to every other node. Major nodes are connected.
each node is connected to every other node。
For high cost reasons, Fully interconnected mesh network.seldom implemented .
Figure A mesh network.

27. Chapter 2 Network Classification
2.4.4 Bus Network
It is a communication medium to which multiple nodes are attached.
medium[`mi:djəm]n.媒介,
Bus topologies are frequently used for LANs.
Figure A bus network.

28. Chapter 2 Network Classification
使用总线的两种网络，以太网和苹果网。
Ethernet：networking technologies for LAN
Local talk：Apple Computer Inc. invented the use of a bus topology of the LAN .

29. Chapter 2 Network Classification
. Local talk：Apple Computer Inc. invented the use of a bus topology of the LAN .

30. Chapter 2 Network Classification
Advantages:
Very high speed transmission.
High reliability, All stations are independent of one another.
Are limited in the distance they can traverse.
Easy to implement and extend.
Requires less cable length than a star topology
Well suited for LAN.
Cheaper than other topologies.

31. Chapter 2 Network Classification
Disadvantages
Limited cable length. If there is a problem with BUS, the entire network goes down. faults can be difficult to locate.. It works best with limited number of nodes. Performance degrades as additional computers are added or on heavy traffic. collision.
传输率高，距离有限。
出现问题时，很难定位错误根源。必须顺序检查所有设备。
degrade [di`ɡreid]vt.使降级
collision [kə`liʒən]n.碰撞,

32. Chapter 2 Network Classification
CSMA/CD (Carrier Sense Multiple Access/Collision Detect)
Send message
examines signal-
if free –transmit
CSMA/CD（Carrier Sense Multiple Access/Collision Derect），即载波监听多路访问/冲突检测方法是一种争用型的介质访问控制协议 。
CSMA/CD协议简单、可靠，其网络系统（如Ethernet）被广泛使用。
or –wait for free.

33. Chapter 2 Network Classification
CSMA/CD (Carrier Sense Multiple Access/Collision Detect)
CSMA/CD（Carrier Sense Multiple Access/Collision Derect），即载波监听多路访问/冲突检测方法是一种争用型的介质访问控制协议 。
CSMA/CD协议简单、可靠，其网络系统（如Ethernet）被广泛使用。

34. Chapter 2 Network Classification
每个站在发送数据帧之前，首先要进行载波监听，只有介质空闲时，才允许发送帧。这时，如果两个以上的站同时监听到介质空闲并发送帧，则会产生冲突现象，失败。然后随机延时一段时间后，再重新争用介质，重发送帧。

35. Chapter 2 Network Classification
2.4.5 Ring Network
A ring network is a network topology in which each node connects to exactly two other nodes, forming a circular pathway for signals - a ring. Data travels from node to node, with each node handling every packet.
环网是这么一个网络拓扑结构，每个节点连接到两个其他节点，为信号形成一个环形通道。
数据传输节点到节点，每个节点处理数据包。

36. Token-Ring Chapter 2 Network Classification 1970 ,IBM Token-Ring A B C忙
A->C A B C D
When to send a message, they must wait for the free tokens through the station, and then will be busy token status, and sending data to the ring. 闲
A->C 忙
A->C 转发
A->C 接收

37. The stations on a ring network:
Chapter 2 Network Classification
The stations on a ring network:
are equal. regenerate a signal before passing it on. check the address of all incoming signals. are connected to the ring with a tap.
Equal [`i:kwəl] adj.相等的
工作站都是平等，并且必须积极参与，从而使换能够运转。
重新生成信号，好处信号不易衰减。另外可检测信号错误。
通过接头连接到环上。

38. Chapter 2 Network Classification
IBM Token Ring 、 FDDI Fiber Distributed Data Interface Once a backbone level of mainstream technology, has been suspended SDH RPR
Example
(光纤分布数据接口)
suspend [sə`spend]vt. 暂停

39. Chapter 2 Network Classification
Advantages
Very orderly network where every device has access to the token and the opportunity to transmit. Performs better than a bus network under heavy network load (no Collision), Can create much larger network Regeneration the signal. Device check the signal for errors
非常整齐访问并且有机会平等传播。
重新生成信号，信号不易衰减。
检测信号错误，支持更复杂差错控制和网络管理。

40. Chapter 2 Network Classification
Disadvantages
One malfunctioning workstation can create problems for the entire network . Moves, adds and changes of devices can affect the network . Network adapter cards and MAU's are much more expensive than Ethernet cards and hubs . Much slower than an Ethernet network under normal load .
malfunction [,mæl`fʌŋkʃən]n.故障, 障碍
IBM 东西贵。

41. A ring network with two channels.
Chapter 2 Network Classification
A ring network with two channels.
Transmit the data in opposite directions.
channel [`tʃænl]n.海峡通道 opposite [`ɔpəzit] prep. 对面的 direction [dai`rekʃən]n.指导;方向,
为什么环形网络通常采用两个沿相反方向传输数据的环？
即使某个节点失败也能够继续下去，当发生失败时，失败位置两边的节点自行重新
配置，从而开吃使用第二个环在相反方向传输数据。
Why have two rings and in opposite directions ?
Links fails ,reconfigure themselves to begin to transmit data.

42. 2-5 NETWORKS CLASSIFIED BY OWNERSHIP
Chapter 2 Network Classification
2-5 NETWORKS CLASSIFIED BY OWNERSHIP
2.5.1Private Networks
It is usually built by an organization for its exclusive use.
a network that uses private IP address space。
exclusive
[iks`klu:siv]adj.高级的, 奢华的、专用的 constituency [kən`stitjuənsi]n.赞助者 common carrier 公用运输业者
He often goes to the exclusive restaurants.
他经常去高级饭馆。
专用的; 独家的
专用网络通常是为组织的专有用途而建立
可以单独建立网络，
错误理解：
*A private network is a network built and owned by a communications company, a common carrier, or another organization for use by its customers or other constituency.F

43. Advantages And Disadvantages
Chapter 2 Network Classification
Advantages And Disadvantages
It can make better use of circuits than a public network could. Can be made from circuits acquired from a communications carrier. It give the company full control of the network's operation and provides better security. May be connected to a public network. May be more expensive on communication than public networks.
advantage [əd`vɑ:ntidʒ]n.有利条件, 有利因素, 优势 acquire [ə`kwaiə]vt.获得 expensive [iks`pensiv]adj.昂贵的,
比公共网络更好地利用线路，对网络进行完全控制，并提供更好的安全性。
可以用通信运营商处获得的线路来建。
私有网络进行通信的代价可能比公共网络更高。

44. Chapter 2 Network Classification
2.5.2 Public Networks
It is a network built and owned by a communications company, a common carrier, or another organization for use by its customers. Uses Public IP. INTERNET

45. VPN（Virtual Private Network）
Chapter 2 Network Classification
VPN（Virtual Private Network）
As public and private networks have merits, the merits of a combination of the two new technologies emerged
虚拟专用网络 virtual [`və:tjuəl]虚拟的
merit [`merit]n.功勋, 优点; 价值 emerge [i`mə:dʒ]vi. 出现 combination [,kɔmbi`neiʃən] n.合作, 结合, 组合
因为公共网和私有网都有优点，两种新技术合并出现的优点。

46. 2.6 Other Types Of Networks
Chapter 2 Network Classification
2.6 Other Types Of Networks
2.6.1 VAN (value added networks) It is a particular type of public data network that ,in addition to offering transmission facilities, Contains intelligence. Van in the application of e-commerce Bank SWIFT Airline SITA Insurance IVANS
contain[kən`tein]vt.包含 intelligence [in`telidʒəns]n.智力,
是一种特殊类型的公共数据网络，除了提供传输功能，还包含一定智能。
增值网络
银行、航空、旅游。

47. Chapter 2 Network Classification
2.6.2 Wireless network
Networks classified by the transmission 　medium A wireless network always uses unguided medium.
classified [`klæsifaid]v.分类 medium [`mi:djəm]n.媒介 unguided [,ʌn`ɡaidid]n.非制导的
Wireline networks
wireless network

48. WSN Chapter 2 Network Classification
Wireless networks（WSN ） are among the most rapidly growing segments of networking technology today. A wireless network uses radio frequency technology as an extension of, or as an alternative to, a wired network. Wireless networks don't cause interference to commercial radio stations.
Extension [iks`tenʃən] n.延伸, frequency [`fri:kwənsi] n.频率
无线网络利用无线射频技术作为对有线网络的扩展或替代技术。
interference [,ɪntə`fiərəns]n.干涉 commercial [kə`mə:ʃəl]adj.商业的
检索了1995年至2005年的国内外有关临床医学、医疗设备、医学信息化建设、无线技术等方面的相关文献。尚未发现无线局域网对医疗设备干扰的报道，也没有发现因使用无线局域网技术而危害病人医疗安全或发生医疗纠纷的报道。

49. Chapter 2 Network Classification
WLAN WIFI
WLAN: Wireless Local Area Network WIFI: Wireless Fidelity
WIFI (无线保真技术),正确读音是[wai] [fai] Wireless Local Area Network(无线局域网络) fidelity    [fiˈdeliti] n. 忠诚,逼真度
WIFI与WLAN有何区别? WIFI属于WLAN技术中的一种,是无线局域网的一种连接方式. .WLAN的覆盖范围有限,一般民用无线网络环境仅在AP周围20～100米内有效.
国行手机为何阉割WIFI功能？ 目前中国对WIFI手机的政策属于模糊政策,即并没有明文规定不允许WIFI手机接入网络,但实际上又不允许WIFI手机通过入网检测,也不向WIFI手机发放入网许可证.WIFI手机的一大亮点是可以实现VOIP网络电话功能,只要在WIFI热点覆盖区域就可以通过互联网免费或者以低廉的价格拨打语音电话,WIFI手机将严重冲击现有运营商的语音市场,也会分流包括电信已有的语音业务,一旦全面推广,将遭到其他运营商的强力反对.这是一个不得不需要权衡的问题,毕竟目前国内几大电信运营商的很大一部分收入来源仍然依靠传统的语音业务.另外普遍认为与中国目前大力推行自主制定标准的WAPI也有关系.

50. Chapter 2 Network Classification
2.6.3 Backbone Network
It is the main network in an organization or a location . Carries the most traffic and is the most critical. Backbone is relative .
backbone [`bækbəun] n.脊骨, 脊柱骨干, 主干网络 traffic [`træfik] n. 交通
critical [`kritikəl] adj.决定性的, 关键性的, 危急的
relative [`relətiv] adj.相对

51. Chapter 2 Network Classification
CERNET Backbone at 2.5G Mbps /155 Mbps 南京 合肥 重庆 上海 福州 广州 昆明 郑州 北京 西安 武汉 长沙 南昌 南宁 湛江 海口 成都 长春 深圳 沈阳
地区中心 地区主节点 网管系统 桂林 杭州
石家庄 太原 青岛
哈尔滨 济南 天津 大连 厦门
2.5G
155M
When looking at a network topology, it is always easy to pick out the backbone network .
2.5G
155M

52. NETWORKS CLASSIFIED BY SERVER FUNCTION
Chapter 2 Network Classification
NETWORKS CLASSIFIED BY SERVER FUNCTION
Server-Based To transit server.
基于服务器来分

53. Chapter 2 Network Classification
Client/Server
客户/服务器 Client 客户机程序.

54. Peer-to-Peer Chapter 2 Network Classification NO SERVER，Each other.

55. NETWORKS CLASSIFIED BY DATA TRANSMISSION
Chapter 2 Network Classification
NETWORKS CLASSIFIED BY DATA TRANSMISSION
Unicast Multicast BROADCAST
Unicast communication is one-to-one.
Multicast communication is one-to-many.
Broadcast communication is one-to-all.
broadcast [ˈbrɔ:dkɑ:st] n.广播; 播音

56. Chapter 2 Network Classification
Unicast vs. Multicast
Server
Router
Unicast
Server
Router
Multicast
Unicast transmission sends multiple copies of data, one copy for each receiver
Ex: host transmits 3 copies of data and network forwards each to 3 separate receivers
Ex: host can only send to one receiver at a time
Multicast transmission sends a single copy of data to multiple receivers
Ex: host transmits 1 copy of data and network replicates at last possible hop for each receiver, each packet exists only one time on any given network
Ex: host can send to multiple receivers simultaneously

57. NETWORKS CLASSIFIED BY LINE CONFIGURATION
Chapter 2 Network Classification
NETWORKS CLASSIFIED BY LINE CONFIGURATION
LINE CONFIGURATION
线结构 点对点 多点
POINT TO POINT
MULTIPOINT

58. Chapter 2 Network Classification
Point-to-Point Line Configuration
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

59. Chapter 2 Network Classification
shortcomings
shortcoming [`ʃɔ:tkʌmiŋ]n.
短处如果连接太多电脑，会产生太多的连接。浪费线。
Too many connections 

60. Chapter 2 Network Classification
Multipoint Line Configuration
multipoint [`mʌltipɔint] adj. 多点 configuration [kən,fiɡju`reiʃən] n.构造,
avoid [ə`vɔid] vt.避开, 避免, 预防 Repeatability 隐藏摘、 重复性
分享通道，减少费用。
Sharing communication channel 
Sharing to avoid Repeatability
Reduce costs
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

61. NETWORKS CLASSIFIED BYTRANSMISSION MODE
Chapter 2 Network Classification
NETWORKS CLASSIFIED BYTRANSMISSION MODE
传输模式 simplex [`simpleks] adj.单纯的,单工的 duplex [`dju:pleks] adj.有两部、双工

62. Chapter 2 Network Classification
Simplex
单工通信：通信线路上的数据只能在一个方向上流动。

63. Chapter 2 Network Classification
Half-Duplex
允许数据在两个方向中的任意一个方向上流动，
但在某一时刻，数据只能在其中的一个方向上流动。

64. Chapter 2 Network Classification
Full-Duplex
允许数据同时在两个方向上流动。

65. Chapter 2 Network Classification
2.7 Voice network
Telephone Network PSTN: Public Switched Telephone Network. Sometimes call Public Telephone Network. PSTN is diverse and is highly redundant. PSTN is an example of a mesh network.
PSTN 线路多样且高度冗余。diverse [dai`vəs] adj.不同的, 多种多样的 redundant [ri`dʌndənt] mesh [meʃ]网状 n.
电话网络和计算机网络结构大同小异。

66. Chapter 2 Network Classification
Importance of a CO
CO:central office. Call swithes ，that route and connect telephone call. A serving CO is one that serves telephone customers.
CO:central office.交换机
在公共语音网络中，中心交换局的角色是什么？
为电话客户服务。路由和连接电话。
circuit [`sə:kit]n.电路
feeder cable 电力干线,供电电缆 feeder [`fi:də]n.馈线

67. Chapter 2 Network Classification
Distribution cable<
Feeder cable
Drop wire <
Circuit : connects to tele , pc, or other.
feeder cable
Drop wire 落线 户内出来的线 Distribution cable 分布电缆 。 Feeder cable馈线 多根分布电缆组成。
Figure Residential telephone cabling.

68. Chapter 2 Network Classification
Trunk : as a circuit, connecting telephone swithes or swithing locations.
PSTN is an example of a mesh network.
mesh network makes the PSTN so redundant and fail-safe.
End office=Tolloffice
Trunk
trunk[trʌŋk]n.树干,大象的鼻子.
干线被定义为连接电话交换机或交换位置（局）的线路。中心交换局之间利用多条称为干线的线路互连。
End office 端交换局 toll office 长途局=switching office
终端交换局与中继局之间的差别？
Endoffice servers telephone within a specific geographic area。
Swithching office are designed primarily for forwarding long distance call to other parts of the country。
Fail 【feil】-Safe 故障保险 redundant [ri`dʌndənt] adj.冗余
哪些因素使PSTN高度冗余和不易受故障影响？采用了网状结构。
Figure The connection of the COs in the nationwide telephone network.

69. Chapter 2 Network Classification
Local loop
In telephony, the local loop is the physical link or circuit, that connects from the demarcation 界线 point of the customer premises房屋 to the edge边 of telecommunications service provider。
连接交换机为干线的定义。
local [`ləukəl]adj.地方性的 loop [lu:p]n.圈, 环, 回路, 循环 回去的路
在电话学上,本地回路是从用户房子边界点到电信服务提供者连接的物理线路或电路,
*A loop is defined as a circuit that connects telephone switches or switching locations. F

70. Chapter 2 Network Classification
Modem
Using voice band (<4K Hz) V.92 at 56Kbps
Internet
Public Switching Telephone Network
modem
modem
PSTN
Internet Service Provider

71. Telephone network classification
Chapter 2 Network Classification
Telephone network classification

72. Chapter 2 Network Classification
Analog Switched Service
analog [`ænəlɔɡ]n.模拟
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

73. Chapter 2 Network Classification
Analog Leased Service
模拟租用服务
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

74. Chapter 2 Network Classification
Analog Hierarchy
hierarchy [`haiərɑ:ki]n.等级

75. Chapter 2 Network Classification
Switched/56 Service
 The McGraw-Hill Companies, Inc., 1998
WCB/McGraw-Hill

76. Chapter 2 Network Classification
DDS
WCB/McGraw-Hill
 The McGraw-Hill Companies, Inc., 1998

77. Chapter 2 Network Classification
DS Hierarchy
hierarchy [ˈhaiərɑ:ki]n.等级制度 DS abbr. n.数字服务,
 The McGraw-Hill Companies, Inc., 1998
WCB/McGraw-Hill

78. 2.7.2Private Voice Networks
Chapter 2 Network Classification
2.7.2Private Voice Networks
PBX :Private Branch Exchange.
private [`praivit]adj. branch [brɑ:ntʃ]n.树枝 exchange [iks`tʃeindʒ]n.交换, 互换
专用小交换机。
私人企业或集团的电话 或 企业内部电话交换系统
电信推出虚拟网以后，很多企业单位取消。
电话公司中心交换局中的交换机与PBX有何不同？
她可以向电话用户提供更多特征。其次，要增加人员维护。
内部通话免费。

79. Chapter 2 Network Classification
2.8 HYBRID NETWORKS
A network that has several topologies is called a hybrid network. It which blend the most appropriate恰当的combinations of capabilities能力to meet the requirements of an organization and the ways in which it uses networks.
hybrid [`haibrid ] 杂种 blend [blend]vt. & vi.(使)混合 appropriate [ə`prəuprieit]vt..适当的, combination [,kɔmbi`neiʃən]n.合作, 结合,
该类网络最大可能地融合各种网络功能来满足各组织的功能需求及网络使用方式方面的需求。

80. Chapter 2 Network Classification
Hybrid networks are often implemented.
hybrid [`haibrid]n.杂交 混合型网络, reality [ri`æliti]n.现实, implement [`implimənt]vt.使生效, 贯彻, 执行
混合 网络常常使用,现实中网络是混合网络.
The reality of networking is hybrid networks.
Only small networks, use a single topology or technology.

81. Examples of actual campus network topology
Chapter 2 Network Classification
Examples of actual campus network topology
actual [`æktʃuəl]adj.实际的 campus [`kæmpəs]n.(大学)校园 topology [tə`pɔlədʒi]n.拓扑,布局

82. Chapter 2 Network Classification
中国矿业大学
核心层
汇聚层
Cernet
电信1
电信2
RG-SAM认证计费平台
STAR-S2150G/S2126G
综合网络管理平台
服务器群
接入层 2台
（RG-S6810）
一卡通核心
学院中心
行政楼中心
图书馆中心
实验室
一卡通 核心
双核心

83. Chapter 2 Network Classification
大连海事大学
RG-S6806E
万兆核心层
STAR-S2126G
STAR- S
1000M
10G
RG-S6810E
RG-SAM安全
计费管理平台
服务器群
100M
Internet
Cernet

84. Chapter 2 Network Classification
2.9 INTERCONNECTING NETWORKS
KEY TERMS
Internetwork
internet
Internet
Subnetwork
subnet [,sʌb`net]n.子网络
I 大写专指因特网，i小写指一个或多个不同网络互连。
为什么公司希望互联？
因为希望能与组织内部或外部的其他人建立通信、发送查询请求或在各种不同网络处理数据，不需要考滤网络是如何连接。

85. Internetworking=internet
Chapter 2 Network Classification
Internetworking=internet
distinct [dis`tiŋkt]adj.截然不同的component [kəm`pəunənt] n.成分 子网是互连网络的组成部分。
When one or more distinct networks are interconnected, the result is called an internet. Subnetworks are components of internetworks.

86. Chapter 2 Network Classification
why interconnected ？
Communication technology has advanced.
WANs, MANs, and LANs all need to be interconnected.
Subnetworks are components of internetworks.
advanced [əd`vɑ:nst]adj.超前的, 先进的
为什么将网络互连？
随着通信技术的发展，这种网络之间的互连已成为可能。
作为一个合格的网络，互连的设备没有必须一定要求不同型号和使用多种技术。
WAN-WAN LAN to LAN MAN TO MAN
子网组成网络互连。
component [kəmˈpəunənt]n.成分
To qualify as a network, the devices that are interconnected must not be of different types and use multiple technologies . .

87. Chapter 2 Network Classification
The Internet
It was designed before LANs existed. started as the creation of a small group of esearchers. It is one example of an internet has grown to be a commercial service.
因特网早于局域网。exist [iɡ`zist]vi存在
最初由一个很小的研究小组创建。grown [ɡrəun] 成长. commercial [kə`mə:ʃəl]adj.商业的, 商务的
长大的;
发展成一项商业服务
它是网络互联的例子
人们使用电话机通过拨号接入因特网时，他们处于在线的时间比标准语音电话呼叫更长。
对电信非常有利。
When people use the telephone to make a call to access the Internet, they stay online longer than if they were making a standard voice telephone call .

88. Chapter 2 Network Classification
SUMMARY
Networks can be classified by many ways. Geographic and technical distinctions between LANs and WANs. Choose Private or public network? Actual topologies are seldom pure. Hybrid topologies are very common.
summary[`sʌməri]n.摘要,
distinction [dis`tiŋkʃən] n.区别, seldom [`seldəm]adv.很少, 罕见 actual [`æktʃuəl].现实的, 实际的;
common [`kɔmən]adj.普遍的
企业还必须确定利用公共网络，还是专用网络所支持网络控制和特许能力。

89. Exercises Chapter 5 Data coding 课后习题
1.Networks that cover a small geographic area are called （　　 ）. C ×
A、 MANs ×
B、 SGANs √
C、 LANs ×
D、 hybrid networks
Redo
Next
Answer

90. Exercises Chapter 5 Data coding 课后习题
2. Networks that cover a broad geographic area are called （　　 ）. D ×
A、hierarchical networks ×
B、 BGANs ×
C、 ring networks √
D、 WANs.
Redo
Next
Answer

91. Exercises Chapter 5 Data coding 课后习题
3. Networks in which all circuits radiate from a central node are called （　　 ）. D ×
A、 radial arm networks ×
B、 pinwheel networks ×
C、 hierarchical networks √
D、 star networks.
Redo
Next
Answer

92. Exercises Chapter 5 Data coding 课后习题
4.A network in which the top node in the structure is called the root node is called a(an) （　　 ）. C ×
A、 tree network ×
B、 plant network √
C、 hierarchical network ×
D、 internetwork
Redo
Next
Answer

93. Exercises Chapter 5 Data coding 课后习题 5. A wireless network always （ ）.×
A、 has a mesh topology ×
B、 has no nodes √
C、 uses unguided media ×
D、 connects to a wired network
Redo
Next
Answer

94. Chapter 3 Network Architetures and Standarts
课后习题
Exercises
network
6.A communications ___________ is an interconnected system of computers, terminals, and other hardware established for the purpose of exchanging information or services between individuals, groups, or institutions.
Answer
7. A ________ on a network is a point of connection into a network, such as a computer terminal, or a point, such as a router or a switch, at which one or more transmission lines (circuits) interconnect.
node
Answer

95. Chapter 3 Network Architetures and Standarts
课后习题
Exercises
8.Three ways that networks can be classified are
__________ _____________ and___________
geography topology ownership
Answer
9.A ________ ________ network covers a small geographic area such as an office of a campus.
local area
Answer

96. Chapter 3 Network Architetures and Standarts
课后习题
Exercises
10.A ________ ________ network covers a small geographic area such as an office of a campus.
wide area
Answer

97. Thank You ! zhongt@gxmu.net.cn That’s all for today． Class is over．
Good bye．／Bye．／See you next time．