chuong 7 - tang ung dung

7/29/2019 Chuong 7 - Tang Ung Dung

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Chng 7:

Tng ng dng

D n HEDSPI

Khoa CNTT- HBK H Ni

Ging vin: Ng Hng Sn

B mn Truyn thng v Mng my tnh


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Tng quan

Bui trc: Tng giao vn Nguyn l ca tng giao vn

TCP v UDP

Khi nim kim sot lung v kim sot tcnghn

Hm nay: Tng ng dng

Nguyn l ca tng ng dng Case study: HTTP, Mail, FTP


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Khi nim c bn


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Nhc li v kin trc phn tng

Application

(HTTP, Mail, )

Transport

(UDP, TCP )

Network

(IP, ICMP)

Datalink

(Ethernet, ADSL)

Physical

(bits)

H tr cc ng dng trn mng

Truyn d liu gia cc ng dng

Chn ng v chuyn tip gi tin giacc my, cc mng

H

tr

vic truy

n thng cho cc thnhphn k tip trn cng 1 mng

Truyn v nhn dng bit trn ngtruyn vt l


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ng dng trn mng?

CHATGAME

ON LINE

WEB

MAIL

SKYPE

YOUTUBE

SSHTELNET

FTP

VoD

SCHOOL

ON THEINTERNET

GOOGLE

BITTORENTE-COMMERCE

EBAY

MUSIC ONLINE

GRID

VIDEOCONFERENCE

e-BANK

VoIP

NEWS

SMS

e-Office

e-Goverment


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ng dng v giao thc ng dng

ng dng :

Cc tin trnh (c giao tip vinhau) trn Internet Hot ng trn cc h thng

cui Trao i thng ip

Giao thc ng dng nh ngha cc quy tc giao tip S dng cc dch v giao vn

(TCP/UDP)

V d ng dng/giao thc: Web (HTTP)

Mail (SMTP/POP/IMAP)

applicationtransportnetwork

data linkphysical

applicationtransportnetworkdata linkphysical

applicationtransport

networkdata linkphysical


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Cc thnh phn ca ng dng

Giao din NSD: H tr cho NSD lm vic vi ng dng, e.g. trnh duyt

Web (Firefox, IE), chng trnh gi th (Thunderbird,Outlook,..)

Ci t cc giao thc v s dng dch v giao vn

Tin trnh ng dng: mt chng trnh ang chy

Cc tin trnh giao tip ntn?

Trn mt my: IPC (inter-process communication) Gia cc my trn mng: Giao thc ng dng

Socket


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Giao tip gia cc tin trnh trnInternet

Nhc li: Socket l mt giao

din gia tin trnh ng dngv tng giao vn Socket c nh danh bi

S hiu cng

a chIP Kiu giao thc giao vn

(TCP hay UDP)

Socket API (Application

Programming Interface): Chophp cc tin trnh la chntham s, la chn dch v

process

transportlayer

services

socket

host orserver

process

transport

layerservices

socket

host orserver

Internet

controlled by

app developer

controlled

by OS


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Cc m hnh ng dng

Khch-ch

P2P

M hnh lai


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M hnh khch ch Khch

Gi yu cu truy cp dch vn my ch

C th c a chIP ng hayvo mng khng thng xuyn

V nguyn tc, khng lin lctrc tip vi cc my khch

khc Ch

Thng xuyn online a chIP tnh

C th c my ch d phng nng cao hiu nng, phng sc

e.g. Web, Mail,

client

client

client

client

Server


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M hnh im-im thun ty Khng c my ch trung tm

Cc my c vai tr ngangnhau

Hai my bt k c th lin lctrc tip vi nhau

C th c IP ng, khng cnvo mng thng xuyn

E.g. Gnutella

PeerPeer

Peer

Peer Peer

Peer


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M hnh lai

Mt my ch trung tm

qun l NSD, thngtin tm kim Cc my khch s giao

tip trc tip vi nhau

sau khi ng nhp E.g. Skype

My ch Skype qun lcc phin ng nhp, mt

khu Sau khi kt ni, cc my

s gi VoIP trc tip chonhau

Server

Client

Client

Client

Client-Server Comm.

P2P Comm.


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Case study 1: HTTP v WWW


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HTTP v Web

WWW: World Wide Web

trao i ti liu siu vn bnHTML (HyperText MarkupLanguage) trn Internet

HTTP: HyperText Transfer

Protocol M hnh Client/Server

Client yu cu truy nhp ti cctrang web (cc i tng web)

v hin th chng ln trnh duyt Server: Nhn yu cu v tr li

cho client

httprequest

httprequ

est

http

resp

onse

httpresponse

Web clients

Web

server

IE

Firefox

Navigator


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HTTP hot ng ntn?

Server m mt TCP socket ch ti cng 80 (default)

Client khi to mt lin kt TCP ti server Server chp nhn yu cu to lin kt

Trao i thng ip HTTP (giao thc ng dng) HTTP Request

HTTP Response

ng lin kt TCP


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Khun dng HTTP request

M ASCII (d dng c c di dng vn bn)

GET /dccn/index.html HTTP/1.1

Host: www.it-hut.edu.vn

User-agent: Mozilla/4.0

Connection: close

Accept-language:en-us

(extra carriage return, line feed)

request line(GET, POST,

HEAD commands)

headerlines

CR, LF

indicates endof message


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Khun dng HTTP response

HTTP/1.1 200 OK

Connection close

Date: Tue, 16 Mar 2008 12:00:15 GMT

Server: Apache/1.3.0 (Unix)

Last-Modified: Mon, 15 Mar 2008 ...Content-Length: 8990

Content-Type: text/html

data data data data data ...

status line

(protocolstatus codestatus phrase)

headerlines

data, e.g.,requestedHTML file


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Cc lin kt HTTP

HTTP khng duy tr

Chmt i tng webc gi qua lin ktTCP

S dng mc nhtrong HTTP/1.0

HTTP 1.0: RFC 1945

HTTP c duy tr

Nhiu i tng c thc gi qua mt linkt TCP.

S dng mc nhtrong HTTP/1.1

HTTP 1.1: RFC 2068


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Hot ng ca HTTP/1.0

Time Time

Web client Web server

TCPConn.Req.

GET/index.html

index.html

Accepted

Init TCP connection

Send HTTP response: index.html

Close TCP connection

OK, send HTTP request

Accept TCP connection

GETimg1.jpg

Parse index.html: has 10reference to 10 images

Repeat above steps 10times!

Send images 1

Close TCP connection

TCPConn.Req.

img1.jpg


2xRTT


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Hot ng ca HTTP/1.1

Time Time


TCPConn.Req.

GET/index.html

GET

index.html

Accepted

Init TCP connection

Send HTTP

response: index.html



GET

img1.jpg

request images 2


request images 1

Send images 1

Send images 2

request images 10

Stop-and-

wait!

Pipeline


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HTTP/1.1 vi pipeline

Time Time


TCPConn.Req.

GET/index.html

GET

index.htm

l

Accepted

Init TCP connection

Send HTTP

response: index.html




request images 1 -10

Send images 1-10


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Cc phng thc trong thng

ip yu cu

HTTP/1.0

GET POST

HEAD

yu cu my ch loi mts i tng ra khi thngip tr li

HTTP/1.1

GET, POST, HEAD PUT

ti file ln my ch, ngdn chra trong URL, file

trong body DELETE

Xa file chra bi ngdn

Lu : C 2 cch gi tham s n server: POST hoc GET

http://www.google.com/search?q=computer+network&flags=68&num=10


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M trng thi tr li

200 OK

request succeeded, requested object later inthis message

301 Moved Permanently requested object moved, new location specified

later in this message (Location:)

400 Bad Request

request message not understood by server404 Not Found

requested document not found on this server

505 HTTP Version Not Supported

Trong dng u tin ca thng ip tr li, v d


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B m- Caching Cache: B nh m

Khi nim b nh cachetrong my tnh L1 cache, L2 cache

cache miss, cache hit

Xem xt trng hp sau: Mt t chc c mt ng

ni ti Internet Tt c lu lng truy cp

web u i qua lin kt ny Nhiu NSD web c th

cng truy nhp ti cng mtni dung

Gii php ci tin?

www.xyz.com/index.htm


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S dng b m web - proxy

NSD t tham s kt nitruy cp web ca trnh

duyt qua mt my chproxy

trnh duyt gi yu cun proxy Miss: Proxy gi yu cu

ti my ch web, tr litrnh duyt v lu mi tng web

Hit: Proxy tr i tngweb cho trnh duyt

client

Proxyserver

client

HTTP

reques

t

HTTP

respon

se

HTTPrequest H

TTPreq

uest

Web

server

HTTPresponse HTT

Prespons

e


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Web caches

Proxy: Va l client, va l server

S dng bi cc ISP nh, cc t chc nh trnghc, cng ty

nh hng ca proxy Lm gim lu lng web trn ng ra Internet C th lm gim thi gian p ng

Th phn tch vi trng hp

cache hit cache miss

proxy b qu ti

Trang web thay i/trang web ng?


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Phng thc GET c iu kin Mc ch: My ch s

khng gi i tng webnu proxy cn lu gi thngtin cp nht

Proxy: chra thi gian cca i tng

If-modified-since:

server: Xc nhn li c thayi hay khng:

HTTP/1.0 304 Not Modified

proxy server

HTTP request msgIf-modified-since:

HTTP responseHTTP/1.0

304 Not Modified

objectnot

modified

HTTP request msgIf-modified-since:

HTTP responseHTTP/1.0 200 OK

objectmodified


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Th in t Chng trnh c/son tho th

Ly th t my ch, gi th nmy ch

e.g. Outlook, Thunderbird

My ch th in t: Cha hp th n ca NSD (mail

box) Hng i gi th i e.g. Sendmail, MS Exchange

useragent

mailserver

mailserver user

agent

Giao thc:

Chuyn th: STMP-SimpleMail Transfer Protocol

nhn th POP Post Office Protocol

IMAP Internet MailAccess Protocol

SMTPPOP

IMAP

Mail box Message queue

IMAP

POP

SMTPSMTP


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Giao thc SMTP

RFC 2821

TCP, port 25: Chuyn th t client n server vgia cc server vi nhau 3 giai on

Lp lin kt Chuyn th ng lin kt

Tng tc yu cu/tr li Yu cu: Lnh vi m ASCII Tr li: m trng thi v d liu


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Cc giao thc nhn th

POP: Post Office Protocol [RFC 1939]

ng nhp v ly ht th v

IMAP: Internet Mail Access Protocol [RFC 1730]

Phc tp hn POP Cho php lu tr v x l th trn my ch

Quota?

HTTP: gmail, Hotmail, Yahoo! Mail, etc.

useragent

senders mailserver

useragent

SMTP SMTP accessprotocol

receivers mailserver


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Khun dng thng ip th in

tSMTP: Giao thc truyn

thRFC 822: nh ngha khundng

Phn u To:

From:

Subject:

Phn thn m ha di dng m

ASCII

header

body

blankline


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chuyn d liu a phng tin:

multimedia extensions MIME: multimedia mail extension, RFC 2045, 2056

Thm mt dng trong phn u chr khun dng d

liu gi i

From: [email protected]: [email protected]: Picture of yummy crepe.MIME-Version: 1.0Content-Transfer-Encoding: base64Content-Type: image/jpeg

base64 encoded data ....................................base64 encoded data

multimedia datatype, subtype,

parameter declaration

method usedto encode data

MIME version

encoded data


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Case Study 3

ng dng truyn tp


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FTP: File Transfer Protocol

M hnh Client-server

Trao i file gia cc my

RFC 959 S dng TCP, cng 20, 21

TCP dataconnection, port 20

FTP

server

user

interface

FTP

client

local file system remote file system

user

TCP controlconnection, port 21

iu khin Out-of-band : Lnh ca FTP : cng 21

D

li

u: cng 20

NSD phi ng nhp trc khitruyn file

Mt s server cho php NSD

vi tn l anonymous


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Lnh v m tr li

Mt s v d USER username

PASS password

LIST : tr v danh schfile

RETR filename Ly file

STOR filename t fileln my ch

V d v m tr li 331 Username OK,

password required

125 data connectionalready open; transfer

starting

425 Cant open dataconnection

452 Error writing file


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V d v ftp client

C:\Documents and Settings\hongson>ftpftp> ?

Commands may be abbreviated. Commands are:

! delete literal prompt send

? debug ls put statusappend dir mdelete pwd traceascii disconnect mdir quit typebell get mget quote userbinary glob mkdir recv verbose

bye hash mls remotehelpcd help mput rename

close lcd open rmdir

Command line

GUI FTP clients: IE, Firefox, GFTP, .


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Tm tt

M hnh ng dng

Client-server vs. P2P Mt s ng dng v giao thc

HTTP

Mail FTP

V nh, hy tm hiu thm

P2P

Giao din lp trnh Socket


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Bui hc ti: Data-link Layer Cc nguyn l tng Data-link

Mng LAN


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Acknowledgment

Bi ging c s dng cc t liu v hnh v

t: Ti liu ca trng i hc Keio v Ritsumekan

Ti liu Computer Network, a top downapproach ca J.F Kurose v K.W. Ross