1. 데이터 通信
홍익대학교 컴퓨터공학과

2. 강의 목표
데이터 통신과 컴퓨터 통신에 대한 기본 원리 및 구조, 표준안, 그리고 관련 기술과 개념들을 이해한다.

3. 1장 개요
1.1 데이터 통신
1.2 네트워크
1.3 프로토콜과 표준안
1.4 요약

4. 1.1 데이터 통신
~ is the process of communicating information in binary form between two or more points.
~ is the exchange of data(in the form of 0s and 1s) between two devices via some from of transmission medium(such as a wire cable)

5. 기본 특성 전달(Delivery) 정확성(Accuracy) 적시성(Timeliness)
~ must deliver data to the correct destination(the intended device or user)
정확성(Accuracy)
~ must deliver data accurately
적시성(Timeliness)
~ must deliver data in a timely manner

6. 구성 요소
step 1:
step 2:
step 3:
…….
송신자
수신자
전송매체
프로토콜
메시지

7. 구성 요소(cont’d) 메시지(Message) 송신자(Sender) 수신자(Receiver)
~ is the information(data) to be communicated.
(text, numbers, pictures, sound, video or any combination of these)
송신자(Sender)
~ is the device that sends the data message.
(computer, workstation, telephone handset, video camera)
수신자(Receiver)
~ is the device that receives the message.

8. 구성 요소(cont’d) 전송매체(Medium) 프로토콜(Protocol)
~ is the physically path by which a message travels from sender to receiver.
(twisted pair wire, coaxial cable, fiber-optic cable, laser , or radio waves(terrestrial or satellite microwave))
프로토콜(Protocol)
~ is a set of rules that govern data communication.

9. 1.2 네트워크(Networks)
~ is a set of devices(node) connected by media links.
장치(Device)
- computer, printer, any other device capable of sending and/or receiving data generated by other nodes on the network.
링크(Link)
- communication channel

10. 네트워크 평가기준(Network Criteria)
Data communication
network criteria
Performance
Reliability
Security

11. 성능(Performance) Depends on a number of factors. number of users
type of transmission medium(data rate)
hardware
software

12. 신뢰성(Reliability) Frequency of failure
Recovery time of a network after a failure
Catastrophe(큰 재난)
Networks must be protected from catastrophic events such as fire, earthquake, or theft.

13. 보안(Security)
Unauthorized access
Virus

14. 네트워크 응용(Application) Marketing and sales Financial service
Manufacturing
Electronic message
Directory service
Information service
Electronic data interchange
Teleconferencing
Cellular telephone
Cable television

15. 1.3 프로토콜과 표준안 (Protocol & Standards)
~ is a set of rules that govern data communication
주요 요소
문법(Syntax)
~ refers to the structure or format of the data, meaning the order in which they are presented.
의미론(Semantics)
~ refers to the meaning of each section of bits.
타이밍(Timing)
~ refers to two characteristics(when data should be sent and how fast it can be sent)

16. 표준안 Standards 표준안(Standards) By fact By law
~ are essential creating and maintaining an open and competitive market for equipment manufactures and in guaranteeing national and international interoperability of data and communications technology and processes.
Standards
By fact
By law

17. 표준안(cont’d) by law standard by fact standard
~ are those that have been legislated by an officially recognized body.
by fact standard
~ are often established originally by manufactures seeking to define the functionality of a new product or technology.
proprietary(closed)
~ are those originally invented by a commercial organization as a basis for the operation of its products.
nonproprietary(open)
~ are those originally developed by group or committees that have passed them into the public domain.

18. 1.4 표준화 기구 Standard Creation Committees
ISO(The International Standard Organization)
~ created in 1947
~ voluntary organization
~ is an organization dedicated to worldwide agreement on international standards in a variety of fields(scientific, technological, economic activity)

19. 표준화 기구(cont’d)
ITU-T(International Telecommunication Union - Telecommunication Standards Sector)
~ is an international standards organization related to the United Nations that develops standards for telecommunications.
Two popular standards developed by ITU-T are the V series(data transmission over phone lines) and the X series (transmission over public digital networks)

20. 표준화 기구(cont’d) ANSI(American National Standard Institute)
~ is a nonprofit organization and is the U.S. voting representative to be both the ISO and the ITU-T
IEEE(Institute of Electrical and Electronic Engineers)
~ is the largest national professional group involved in developing standards for computing, communication, electrical engineering, and electronics)
EIA(Electronic Industries Association)
~ is an association of electronics manufactures in the United States. (EIA-232-D, EIA-530 standards)

21. 표준화 기구(cont’d) Bellcore Forums
~ provides research and development resources for the advancement of telecommunications technology.
Forums
~ consist of representatives from corporation that test, evaluate and standardize new technologies.
Frame Relay Forum
ATM Forum and ATM consortium
IETF(Internet Society and Internet Engineering Task Force)