1 Kyung Hee University Prof. Choong Seon HONG Basic Concepts

2 Kyung Hee University Basic Concepts oFive general concepts provide the basis for the relationship between the communicating devices. Line configuration Topology Transmission mode Categories of Networks Internetworks

3 Kyung Hee University 2.1 회선구성 (Line configuration) ~ refers 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

4 Kyung Hee University Line configuration (cont’d) o 점 - 대 - 점 (Point-to-point) ~ provides a dedicated link between two devices. o 다중 점 (Multipoint) : multidrop ~ is configuration in which more than two specific devices share a single link

5 Kyung Hee University Line configuration (cont’d) o 점 - 대 - 점 회선 구성 Link

6 Kyung Hee University Line configuration (cont’d) o 점 - 대 - 점 회선 구성 Link

7 Kyung Hee University Line configuration (cont’d) o 점 - 대 - 점 회선 구성

8 Kyung Hee University Line configuration (cont’d) o 다중 점 회선 구성

9 Kyung Hee University 접속형태 (Topology) ~ refers to the way a network is laid out, either physically or logically ~ defines the physical or logical arrangement of link in a network oA 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 (star, tree)

10 Kyung Hee University 접속형태 분류 (Categories of topology) Topology Mesh Star Tree Bus Ring

11 Kyung Hee University 그물형 (Mesh) oEvery device has a dedicated point-to-point link to every other device. oA fully connected mesh network therefore has n(n-1)/2 physical channels to link n devices.

12 Kyung Hee University 그물형 (cont’d) oMesh topology

13 Kyung Hee University Mesh (cont’d) oAdvantages The use of dedicated links guarantees that each connection can carry its data load. Mesh topology is robust. Privacy and security. Point-to-point links make fault identification and fault isolation easy.

14 Kyung Hee University 그물형 (cont’d) oDisadvantages ~ 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

15 Kyung Hee University 스타형 (Star : 성형 ) oEach device has a dedicated point-to-point link only to a central controller, usually called a hub

16 Kyung Hee University Star (cont’d) oStar topology

17 Kyung Hee University Star (cont’d) oAdvantage Each device needs only one link and one I/O port to connect it to any number of others (easy to install and reconfigure) Robustness l if one link fails, only that link is affected

18 Kyung Hee University 트리형 (Tree) ois a variation of a star active hub(central hub) ~ contains a repeater, which is a hardware device that generates the received bit patterns before sending them out passive hub ~ provides a simple physical connection between the attached devices

19 Kyung Hee University Tree (cont’d) oTree topology

20 Kyung Hee University Tree (cont’d) oAdvantage & Disadvantage are generally the same as those of a star

21 Kyung Hee University 버스형 (Bus) ois multipoint. One long cable acts as a backbone to link all the devices in the network oNodes are connected to the bus cable by drop lines and taps drop line ~ is a connection running between the device and the main cable tap ~ is a connector either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core

22 Kyung Hee University Bus (cont’d) oBus topology

23 Kyung Hee University Bus (cont’d) oAdvantages ~ include ease of installation oDisadvantages ~ include difficult reconfiguration and fault isolation

24 Kyung Hee University 링형 (Ring) oEach device has a dedicated point-to-point line configuration only with the two devices on either side of it oAdvantage ~ is relatively easy to install and reconfigure ~ fault isolation is simplified oDisadvantage unidirectional traffic l break in the ring can disable the entire network --> needs dual ring

25 Kyung Hee University Ring (cont’d) oRing topology

26 Kyung Hee University 혼합형 (Hybrid topology)

27 Kyung Hee University 2.3 전송모드 (Transmission mode) ~ is used to define the direction of signal flow between two link devices o 단방향 (Simplex) is unidirectional, as on a one-way street (keyboard, monitor) o 반이중 (Half-Duplex) each station can both transmit and receive, but not at the same time o 전이중 (Full-Duplex) both stations can transmit and receive simultaneously

28 Kyung Hee University Transmission Mode (cont’d) Transmission modes Half-duplex Simplex Full-duplex

29 Kyung Hee University Transmission Mode (cont’d) o 단방향 (Simplex)

30 Kyung Hee University Transmission Mode (cont’d) o 반이중 (Half-Duplex)

31 Kyung Hee University Transmission Mode (cont’d) o 전이중 (Full-Duplex)

32 Kyung Hee University 2.4 네트워크 분류 (Categories of Networks) othree primary categories 근거리 통신망 (LAN) 도시 통신망 (MAN) 광역 통신망 (WAN) osize, ownership, distance it cover, physical architecture

33 Kyung Hee University Categories of Networks (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

34 Kyung Hee University Categories of Networks (cont’d) oLAN(Local Area Networks) ~ is usually privately owned and links the devices in a single office, building or campus

35 Kyung Hee University Categories of Networks (cont’d)

36 Kyung Hee University Categories of Networks (cont’d) oMAN(Metropolitan Area Networks) ~ is designed to extend over an entire city

37 Kyung Hee University Categories of Networks (cont’d) oWAN(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

38 Kyung Hee University Categories of Networks (cont’d) oWAN

39 Kyung Hee University 2.5 네트워크간 네트워크 (Internetworks) ~ is an interconnection of networks by the use of internetworking device(router and gateway) ocf. internet: an interconnection of networks Internet: a specific worldwide network

40 Kyung Hee University Internetworks (cont’d) oInternetwork (internet)