Network Programming:
Syllabus
Spring 2009,
Prof. Kihyun Pyun
Network Computing Lab. (http://nclab.chonbuk.ac.kr)
1
Evolution of Data
Communication Networks (1)
r A key motivation
r A typical key cost : communication media
installation cost
r Equipments are relatively cheap!
Evolution of Data
Communication Networks (2)
r If a new technology requires a new network
infrastructure, reconsider it!
m
m
m
Is it worth for investing a BIG money?
As an example, think about the video
conferencing technologies in 1970s
xDSL technologies are good examples for
success
Evolution of Data
Communication Networks (3)
r Due to a tremendous initial investment for
a network backbone infrastructure
m
traditionally telecommunication companies leads
the trend
• E.g., FrameRelay, ATM (Asynchronous Transfer
Mode), …
m
existing infrastructures are reused as much as
possible
• However, equipments can be replaced more easily than
transmission media
Evolution of Data
Communication Networks (4)
인터넷 망 전체 구조
인터넷 서비스 제공자
(ISP)
고비용, 기존망 활용
WAN
라우터
가정망
ISP
(케이블 모뎀,
xDSL, etc)
서버
회사망
PC
노트북
무선 AP
저비용, 이더넷
LAN
5
Evolution of Data Communication
Networks (5)
r An example
수십 ~ 수백 Km 거리,
56 Kbps 이하
인터넷 검색
인터넷 연결을 위한
중간 다리 역할
가정
인터넷
컴퓨터
전화 모뎀
전화모뎀
컴퓨터(고성능 컴퓨터)
전화망
가정
컴퓨터
가정
컴퓨터
전화 모뎀
전화모뎀
전화 모뎀
전화모뎀
Evolution of Data
Communication Networks (6)

Another example
300 m 이하 거리,
10 Mbps 이상
인터넷
가정
컴퓨터
전화선로
ADSL 모뎀
분리기
(splitter)
분리기
(splitter)
중계기
(MSLAM)
전화망
300 m 이하 거리,
10 Mbps 이상
가정
컴퓨터
전화선로
ADSL 모뎀
분리기
(splitter)
분리기
(splitter)
Figure 16.1
McGraw-Hill
Connecting devices
©The McGraw-Hill Companies, Inc., 2004
Figure 16.2
McGraw-Hill
Repeater
©The McGraw-Hill Companies, Inc., 2004
Figure 16.3
McGraw-Hill
Function of a repeater
©The McGraw-Hill Companies, Inc., 2004
Figure 16.4
Hubs
Dummy hub : multi-port repeater
McGraw-Hill
©The McGraw-Hill Companies, Inc., 2004
Figure 16.12
McGraw-Hill
Star backbone
©The McGraw-Hill Companies, Inc., 2004
Residential access: cable modems
Diagram: http://www.cabledatacomnews.com/cmic/diagram.html
Introduction
McGraw-Hill
1-13
©The McGraw-Hill Companies, Inc., 2004
Cable Network Architecture: Overview
Typically 500 to 5,000 homes
cable headend
cable distribution
network (simplified)
McGraw-Hill
home
Introduction
1-14
©The McGraw-Hill Companies, Inc., 2004
Cable Network Architecture: Overview
cable headend
cable distribution
network (simplified)
McGraw-Hill
home
Introduction
1-15
©The McGraw-Hill Companies, Inc., 2004
Cable Network Architecture: Overview
server(s)
cable headend
cable distribution
network
McGraw-Hill
home
Introduction
1-16
©The McGraw-Hill Companies, Inc., 2004
Cable Network Architecture: Overview
FDM:
V
I
D
E
O
V
I
D
E
O
V
I
D
E
O
V
I
D
E
O
V
I
D
E
O
V
I
D
E
O
D
A
T
A
D
A
T
A
C
O
N
T
R
O
L
1
2
3
4
5
6
7
8
9
Channels
cable headend
cable distribution
network
McGraw-Hill
home
Introduction
1-17
©The McGraw-Hill Companies, Inc., 2004
Evolution of Data Communication
Networks (6)

A short history
Telegraphic
communication
Message
Telephone
networks
Voice
Telephone and
Data networks
Voice, data
Winner?
ISDN
(Integrated
Services
Digital Network)
Voice, video, data
ALL IP ?!
B-ISDN
(Broadband
ISDN)
Voice, video, data
Internet
Data, voice by VoIP, video
Analog wireless
communications
Voice
McGraw-Hill
Digital wireless
communications
Voice
GSM
Voice
CDMA
Voice, data
CDMA2000,
HSDPA,
…
Voice, video, data
©The McGraw-Hill Companies, Inc., 2004
프로토콜 스택 (Protocol Stack)
 다양한 통신선과 장비가 서로 통신할 수 있도록 정한
규약들
 전화선, 동선, 광케이블 등
 국제 표준화가 필요
 Layering을 통해 복잡성을 줄임
 하위 계층의 기능을 상위 계층에서 활용
Network Computing Lab. (http://nclab.chonbuk.ac.kr)
19
ISO의 OSI reference model
 OSI (Open Systems Interconnection) reference model
 ISO에서 만듦
 7 계층
 참고 모델일 뿐!
Application
Presentation
Session
Transport
Network
Data Link
Physical
Network Computing Lab. (http://nclab.chonbuk.ac.kr)
20
Internet protocol stack
 application: supporting network
applications
m
FTP, SMTP, STTP
application
 transport: host-host data transfer
m TCP, UDP
transport
 network: routing of datagrams from
network
source to destination
m
IP, routing protocols
 link: data transfer between
neighboring network elements
m
link
physical
PPP, Ethernet
 physical: bits “on the wire”
Introduction
1-21
Protocol layering and data
스택구조로 사용
먼저 넣은 것이 가장 늦
게 나옴
Each layer takes data from above
 adds header information to create new data unit
 passes new data unit to layer below
source
M
Ht M
Hn Ht M
Hl Hn Ht M
application
transport
network
link
physical
destination
application
Ht
transport
Hn Ht
network
Hl Hn Ht
link
physical
M
message
M
segment
M
M
datagram
frame
Introduction
1-22
토론 마당
 새로운 선, 예들 들면 USB 선에 연결된 마우스를
인터넷에서 접속하는 것이 가능할까? 어떻게?
 혹은 CDMA망에 인터넷은 어떻게?
TCP
IP
CDMA
CDMA
Physical
Physical
Network Computing Lab. (http://nclab.chonbuk.ac.kr)
23
프로토콜 예제
TCP/IP
TCP/IP
TCP/IP
TCP/IP
TCP/IP
TCP/IP
Ethernet
Ethernet
X.25/…
X.25/…
UTP
UTP
Coaxial
Coaxial
WCDMA/
Wibro
Wireless
channel
WCDMA/
Wibro
Wireless
channel
하부망 특정 프로토콜
(예: ARP, RARP)
하부망 특정 프로토콜
(예: 기지국 찾기, …)
네트워크 프로그래밍은 넓은 관점에서는 위의 모든 프로토콜 영역에 적용할 수 있어야 함.
그러나 하부망 특정 프로토콜 영역은 (소켓프로그래밍에서 Raw 패킷 ) 이 과목에서 주로 다루지 않음
Network Computing Lab. (http://nclab.chonbuk.ac.kr)
24
고려해야 할 프로토콜들
 TCP
 오류없는 데이터 전송 보장
 UDP
 효율적인 데이터 전송 (패킷 소실 가능)
 응용 프로토콜
 FTP, Telnet, …
OSPF
FTP
HTTP
RIP
TCP
UDP
IP
Network Computing Lab. (http://nclab.chonbuk.ac.kr)
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