1 2 장 데이터 통신 기본 개념 2.1 회선 구성 (Line configuration) 2.2 토플로지 (Topology) 2.3 전송 모드 (Transmission mode) 2.4 네트워크 분류 (Categories of Networks) 2.5 인터네트워크 (Internetworks) 2.6 요약

2 2.1 회선 구성 ~ refer to the way two or more communication devices attach to a link. ~ defines the attachment of communication devices to a link Line configuration Multipiont Point-to-point

3 회선 구성 (cont’d) z 점 - 대 - 점 (Point-to-point) ~ provides a dedicated link between two devices. z 멀티포인트 (Multipoint) ~ is one in which more than two specific devices share a single link

4 회선 구성 (cont’d) z 점 - 대 - 점 회선 구성 Link

5 회선 구성 (cont’d) z 점 - 대 - 점 회선 구성 Link

6 회선 구성 (cont’d) z 점 - 대 - 점 회선 구성

7 회선 구성 (cont’d) Link z 다중 포인트 회선 구성

8 2.2 토플로지 (Topology) ~ refer to the way a network is laid out, either physically or logically ~ defines the physical or logical arrangement of link in a network zA consideration when choosing a topology is the relative status of the devices to be linked. ¬peer-to-peer : the devices share the link equally(ring, mesh) ­primary-secondary : one device controls traffic and the others must transmit through it

9 토플로지 분류 (Categories of topology) Topology Mesh Star Tree Bus Ring

10 Mesh zevery device has a dedicated point-to-point link to every other device. zA fully connected mesh network therefore has n(n-1)/2 physical channels to link n devices.

11 Mesh(cont’d) zAdvantages ythe use of dedicated links guarantees that each connection can carry its data load. ya mesh topology is robust. yPrivacy and security. yPoint-to-point links make fault identification and fault isolation easy.

12 Mesh(cont’d) zMesh topology

13 Mesh(cont’d) zDisadvantage ~ are related to the amount of cabling and the number of I/O ports ¬because every device must be connected to every other device, installation and reconfiguration are difficult ­the sheer bulk of the wiring can be greater than the available space(in walls, ceiling, or floors) can accommodate ®the hardware required to connect each link(I/O port and cable) can be prohibitively expensive

14 Star zeach device has a dedicate point-to-point link only to a central controller, usually called a hub

15 Star(Cont’d) zStar topology

16 Star(cont’d) zAdvantage yeach device needs only one link and one I/O port to connect it to any number of others(easy to install and reconfigure) yrobustness x if one link fails, only that link is affected

17 Tree zis a variation of a star yactive hub(central hub) ~ contains a repeater, which is a hardware device that generates the received bit patterns before sending them out ypassive hub ~ provides a simple physical connection between the attached devices

18 Tree(cont’d) zTree topology Hub

19 Tree(cont’d) zAdvantage & Disadvantage yare generally the same as those of a star

20 Bus zis multipoint. One long cable acts as a backbone to link all the device in the network zNodes are connected to the bus cable by drop lines and taps ydrop line ~ is a connection running between the device and the main cable ytap ~ is a connector either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core

21 Bus(cont’d) zBus topology

22 Bus(cont’d) zAdvantage ~ include ease of installation zDisadvantage ~ include difficult reconfiguration and fault isolation

23 Ring zeach device has a dedicated point-to-point line configuration only with the two devices on either side of it zAdvantage ~ is relatively easy to install and reconfigure ~ fault isolation is simplified zDisadvantage yunidirectional traffic xbreak in the ring can disable the entire network(dual ring)

24 Ring(cont’d) zRing topology

25 Hybrid topology

전송모드 (Transmission mode) ~ is used to define the direction of signal flow between two link devices z 단방향 (Simplex) yis unidirectional, as on a one-way street(keyboard, monitor) z 반이중 (Half-Duplex) yeach station can both transmit and receive, but not at the same time z 전이중 (Full-Duplex) yboth stations can transmit and receive simultaneously

27 전송모드 (cont’d) Transmission modes Half-duplex Simplex Full-duplex

28 전송모드 (cont’d) Mainframe Monitor Direction of data z 단방향 (Simplex)

29 전송모드 (cont’d) Workstation Direction of data at time 1 Direction of data at time 2 z 반이중 (Half-Duplex)

30 전송모드 (Full-Duplex) Workstation Direction of data at all the time z 전이중 (Full-Duplex)

네트워크 분류 (categories of Networks) zthree primary categories yLAN yMAN yWAN zsize, ownership, distance it cover, physical architecture

32 네트워크 분류 (cont’d) Metropolitan area network (MAN) Metropolitan area network (MAN) Local area networks (LAN) Local area networks (LAN) Wide area network (WAN) Wide area network (WAN) Network

33 zLAN(Local Area Networks) ~ is usually privately owned and links the devices in a single office, building or campus 네트워크 분류 (cont’d)

34 네트워크 분류 (cont’d) zSingle building LAN

35 네트워크 분류 (cont’d) Backbone zMultiple building LAN

36 네트워크 분류 (cont’d) zMAN(Metropolitan Area Networks) ~ is designed to extend over an entire city

37 네트워크 분류 (cont’d) Public city network zMAN

38 네트워크 분류 (cont’d) zWAN(Wide Area networks) ~ provides long-distance transmission of data, voice, image, and video information over large geographical areas that may comprise a country, a continent, or even the whole world

39 네트워크 분류 (cont’d) zWAN

인터네트워크 (Internetworks) ~ is an interconnection of networks by the use of internetworking device(router and gateway) zcf yinternet: an interconnection of networks yInternet: a specific worldwide network

41 Internetworks(internet)