Thursday, 24 May 2018

O level M@-R4-01-2018

1. A webpage displays a picture. What tag was used to display that picture?
(a) pictur
(b) Image
(c) Img
(d) Src
2. <b> tag makes the enclosed text bold. what is other tag to make text bold?
(a) <strong>
(b) <dar>
(c) <black>
(d)<emp>
3. Which tag inserts a line horizontally on your web page?
(a) <hr>
(b) <line>
(c)<line direction ="horizontal">
(d) <tr>
4. Which of the following protocol is used by remote login?
(a)telnet
(b)ftp
(c)smtp
(d)ntp
5.What  should be the first tag in any HTML document?
(a) <head>
(b) <title>
(c) <html>
(d) <document>
6.

Saturday, 19 May 2018

What is SMTP and which are the default SMTP ports

Simple Mail Transfer Protocol (SMTP) is the standard protocol for sending emails across the Internet.
     By default, the SMTP protocol works on three ports:
  • Port 25 - this is the default SMTP non-encrypted port
  • Port 2525 - this port is opened on all SiteGround servers in case port 25 is filtered (by your ISP for example) and you want to send non-encrypted emails with SMTP
  • Port 465 - this is the port used if you want to send messages using SMTP securely

Monday, 30 April 2018

DOEACC O LEVEL JAN2014 Solved Paper

                                                                             PART ONE
(Answer all the questions)
1. Each question below gives a multiple choice of answers. Choose the most
appropriate one and enter in the “OMR” answer sheet supplied with the question
paper, following instructions therein.                                                                                   (1x10)

1.1 ________ are networks that connect people within a company to each other and to the
company network.
A) Extranets
B) Internets
C) Bitstreams
D) Intranets
1.2 The internet model or TCP/IP reference model specifically applies to internet worked
systems, and has 4 layers. The movement of data packets across a network would be
managed by which layer?
A) The link layer
B) The (inter) network layer
C) The transport layer
D) The application layer
1.3 Which is NOT a good Web security strategy?
A) Restrict access to the Web server; keep a minimum number of ports open
B) Limit the users who can load software, edit or add files.
C) Add demo programs, so users can test system without accessing production data.
D) Remove unnecessary compilers and interpreters.
1.4 A passive threat to computer security is
A) Malicious Intent
B) Sabotage
C) Accident Errors
D) Espionage Agents
1.5 ________ are used to identify a user who returns to a Website.
A) Cookies
B) Plug-ins
C) Scripts
D) ASPs
1.6 E-mail message can be protected by
A) Mirroring
B) Caching
C) Encryption
D) Resending
1.7 Multipurpose Internet Mail Extension (MIME) was developed
A) to support email messages containing text, audio and video
B) to support FTP clients
C) to support telnet between two machines
D) to support text-based email messages only
1.8 The tag used in HTML to link it with other URL’s is:
A) <H>
B) <A>
C) <U>
D) <L>
1.9 HTTP stands for
A) Hyper Text Transfer Protocol
B) Hyper Tetra Transfer Protocol
C) Heavy Text Transfer Protocol
D) Huge Text Transfer Protocol
1.10 A reliable stream service in TCP is described as two-way transmission, free of transmission
________, with no lost or duplicate ________, and the bytes are delivered in the same
________ in which they were transmitted.
A) errors; bytes; manner
B) failure; packets; sequence
C) errors; activity; manner
D) errors; bytes; sequence


2. Each statement below is either TRUE or FALSE. Choose the most appropriate one
and ENTER in the “OMR” answer sheet supplied with the question paper, following
instructions therein.                                                                                                             (1x10)
2.1 The core of Fiber Optic Cable is made of highly refined cylindrical glass.TRUE
2.2 Wi-Fi can be used for connecting two machines without any cable.TRUE
2.3 A socket address comprises the IP address of the host and a port number.TRUE
2.4 TCP is reliable and segments include a checksum field in the header. UDP is unreliable and
therefore has no checksum in its header.TRUE
2.5 ARP is used to find the appropriate IP address, given a MAC address.TRUE
2.6 The Domain Name System (DNS) is primarily used to determine the symbolic name of a
host, given its IP address.TRUE
2.7 A Gigabyte contains 1000 Megabytes.TRUE
2.8 JavaScript embeds a script within an HTML page. When the HTML interpreter reaches the
script it invokes an interpreter which executes it.TRUE
2.9 IPv6 address mappings require a AAAA DNS record.TRUE
2.10 The network address is usually encoded as a prefix of the IP address.TRUE


3. Match words and phrases in column X with the closest related meaning/
word(s)/phrase(s) in column Y. Enter your selection in the “OMR” answer sheet

supplied with the question paper, following instructions therein.                                (1x10)


3.1 IP packet is encapsulated within a new IP packet.                                   A. TCP 9
3.2 Transfer of electronic mail.                                                                      B. UDP 1
3.3 The network protocol that breaks messages into                                     C. List
packets, reassembles the packets at the destination, and                               D. SMTP 2
takes care of errors.                                                                                        E. IP 3
                                                                                                                       F. Tunnel mode   
3.4 Speed of printer is measured in                                                               G. FTP 8 
3.5 A script used to display a non-text based object at a                               H. MIME 10
specified location within a page.                                                                    I. Non-persistent
                                                                                                                        J. Image
3.6 Protocol used to fetch e-mail from a remote mailbox                              K. ppm 4             
3.7 A protocol provides routing and error reporting functions                       L. TELNET
in addition to forwarding, fragmentation/re-assembly and                             M. POP3 6
address resolution
                                                                                                                       
3.8 Used to send/receive files between two computers                                                
3.9 An alternative to TCP that achieves higher transmission
speeds.
                                                                                                                      
3.10 Format of email attachments.                                                                  

DOEACC O LEVEL JAN2013 Solved Paper

                                                                      PART ONE
(Answer all the questions)
1. Each question below gives a multiple choice of answers. Choose the most
appropriate one and enter in the “tear-off” answer sheet attached to the question
paper, following instructions therein.                                                                                          (1x10)
1.1 TCP is a commonly used protocol at
A) Applications layer
B) Network layer
C) Transport Layer
D) Physical Layer
1.2 The domain name in an URL refers to the
A) protocol
B) server
C) filename
D) directory
1.3 Cell base architecture is known as
A) LAN
B) ATM
C) FDDI
D) Client-Server
1.4 Telnet is
A) Terminal network
B) Telephone network
C) Telecommunication network
D) Terrestrial network
1.5 A software that prevents external access to a system is termed as
A) Gateway
B) Firewall
C) Intrusion Prevention system
D) Anti-Virus
1.6 A valid e-mail address is
A) Vml.@india.com
B) @vrm@india.com
C) Vrm.india.com
 D) vrm@india.com
1.7 A web publishing tool developed by Microsoft is
A) Navigator
B) Hot Metal
C) Pagemill
D) Front Page
1.8 Which of the following cable types is generally associated with the linear bus topology
A) Unshielded twisted pair
B) Fiber Optic
C) Thin coaxial cable
D) Telephone cable
1.9 Error detection at a data link level is achieved by
A) Parity
B) Cyclic redundancy code
C) Hamming code
D) Equalization
1.10 On Internet, which version of the Internet Protocol is the most widely used
A) Ipv1
B) IPv6
C) IPv2
D) IPv4

2. Each statement below is either TRUE or FALSE. Choose the most appropriate one
and ENTER in the “tear-off” sheet attached to the question paper, following

instructions therein.                                                                                                                 (1x10)

2.1 Web traffic on Internet is transferred using FTP. True
2.2 ASP is the product of Microsoft. True
2.3 Download means to copy a file from your computer to another.False
2.4 When the cursor pointer changes to a hand you are over a hyperlink.True
2.5 SMTP protocol is used by a mail client program to fetch mail from mail server False
2.6 JavaScript is the default scripting language in ASP.False
2.7 ‘HTTPS’ traffic is encrypted traffic. True
2.8 WAN is based on Ethernet.True
2.9 GIF format is suitable to save a full color photograph.False
2.10 A web browser is also referred to as a web client.True

3. Match words and phrases in column X with the closest related meaning/
word(s)/phrase(s) in column Y. Enter your selection in the “tear-off” answer sheet
attached to the question paper, following instructions therein.                                             (1x10)
                                      X                                                                            Y
3.1 Backbone E. connects two local-area networks                       A. Wireless network
3.2 Wi-Fi A. Wireless network                                                       B. Internet on serial interface
3.3 Ping L. Check network errors                                                  C. Mail
3.4 Throughput K. Communication speed                                     D. Remote access
3.5 SLIPB. Internet on serial interface                                           E. connects two local-area networks
3.6 RDP H. telecommunications network                                      F. File transfer
3.7 POP3C. Mail                                                                            G. Hypertext
3.8 NNTP I. Usenet                                                                        H. telecommunications network
3.9 ISDN F. File transfer                                                                I. Usenet
3.10 BridgeJ. connects large networks                                          J. connects large networks
                                                                                                       K. Communication speed
                                                                                                       L. Check network errors
                                                                                                       M. Routing protocol

4. Each statement below has a blank space to fit one of the word(s) or phrase(s) in the
list below. Enter your choice in the “tear-off” answer sheet attached to the question
paper, following instructions therein.                                                                           (1x10)
A. Client program B. Java C. Gateway D. POP3 E. UDP F. CGI G. Web Server H. FDDI I. JavaScript J. VRML K. Search Engine L. Header M. Router


4.1 Router is a device containing software that help in determining the best path out of the
available paths.
4.2 An application receiving data is called Client program.
4.3 A local area network technology that uses fiber optics to interconnect station in a ring
topology is FDDI.
4.4 Search Engine help to locate PDF files on internet.
4.5 A simple protocol used for fetching e-mail from a remote mailbox is POP3.
4.6 JavaScriptwas originally developed by Netscape for client side validation.
4.7 Web Server is used to deliver web pages and other content to multiple users on Internet.
4.8 Virtual worlds are created using a computer language called VRML.
4.9 C. Gateway is an address used as an entry point into another network.
4.10 CGI is a standard way in which the web interacts with outside resources, such as a
database.

What is Netiquette?

Netiquette is a set of rules for practicing good manners on the Internet.

"Netiquette" refers to Internet etiquette. This simply means the use of goodmanners in online communication such as e-mail, forums, blogs, and social networking sites to name a few. It is important to use netiquette because communication online is non-verbal.

DOEACC O LEVEL JAN 2012 Solved Paper

                                                                          PART ONE
(Answer all the questions)
1. Each question below gives a multiple choice of answers. Choose the most appropriate
one and enter in the “tear-off” answer sheet attached to the question paper, following
instructions therein.                                                                                                                (1x10)
1. The rules with regards to conduct for Internet users is known as
A) Mosaic
B) Netiquette
C) Protocol
D) Internet Protocol

2. TCP/IP is
A) Abbreviation for Transmission Control Protocol and Internet Protocol
B) A suite of networking protocols
C) A standard protocol that lets disparate types of computers communicate over the Net
D) All the above

3. The protocol that allows a computer to use the Internet Protocol with standard voice-grade
telephone line and a high-speed modem is
A) SLIP
B) SMTP
C) SGML
D) RTF

4. A Spider is
A) A Computer virus
B) A Browser
C) A program that catalogs web sites
D) A hacker community

5. FTP does not use
A) Two transfer mode
B) Control connection to remote computer before file can be transferred
C) User Datagram Protocol
D) Authorization of a user through login and password verification

6 A terminal emulation protocol that allows users to log-on to a host computer from remote
computers is
A) Telnet
B) TCP/IP
C) FTP
D) Point-to-Point protocol (PPP)

7 Which of the following is used to enable the use of active documents?
A) HTML
B) CGI
C) JAVA
D) All of the above

8 A networking standard developed by Xerox, Intel and DEC; capable of connecting as many as
1,024 workstations and transmitting data at a maximum speed of 10 Mbps
A) Ethernet
B) FDDI
C) File Transfer protocol
D) Gopher

9 The HTML tags that create a table header are
A) <head></head>
B) <ttop></ttop>
C) <th></th>
D) <td></td>

10 Which of the following is the correct HTML for inserting background image?
A) <background img=”background.gif”>
B) <img src=”background.gif” background />
C) <a href=”background.gif”>
D) <body background=”background.gif”>



2. Each statement below is either TRUE or FALSE. Choose the most appropriate one and ENTER in the “tear-off” sheet attached to the question paper, following instructions therein.

1 Client server computing is the fundamental relationship of computers on the Net (or any
network) in which one computer acts as a client by remotely connecting to another computer
that acts as a server. True

2 Domain name will change if a system’s IP address changes. False

3 Firewall protects an organization’s computer systems from external access.True

4 XML is a cross platform, software and hardware independent tool for transmitting information
over the Net.True

5 Just as HTML, XML also uses predefined tags.False

6 IP only allows fixed packet sizes.False

7 Cipher text is the meaningful form of encrypted message that can be read in transit by anyone.False

8 Meta search engines are search engine tools that pass queries to a maximum of 6 search
engines. True

9 TELNET is a network protocol used on Internet to provide a bidirectional interactive textoriented
communications via a virtual terminal connection. True

10 JavaScript can read and write HTML elements. True

3. Match words and phrases in column X with the closest related meaning/
word(s)/phrase(s) in column Y. Enter your selection in the “tear-off” answer sheet

attached to the question paper, following instructions therein.

                X                                                                                                                 Y
3.1 An internet standard that extends the format of
e-mail to support text in character sets   C. MIME                                       A. EDI System
3.2 A hardware device connected to a host on a LAN                                  B. User Interface
that acts as a gateway between different types of                                        C. MIME
networks D. Router                                                                                       D. Router
3.3 A set of formatting codes for creating documents. G. SGML                E. B2C E-commerce
3.4 A self service model where customers configure                                   F. <HTML> and </HTML>
and customize the products and services they                                              G. SGML
wish to pay E. B2C E-commerce                                                                 H. Dogpile
3.5 An example of metasearch engine H. Dogpile                                      I. Public Key Infrastructure
3.6 The screen in which you type a query and which                                   J. Bing
displays the search resultsB. User Interface                                                K. B2B E-commerce
3.7 Set of computer interchange standards for                                              L. Signature
business documents such as invoices, bills and                                            M. IPv6
purchase orders A. EDI System
3.8 Any web document must began and end withF. <HTML> and </HTML>
3.9 It is automatically appended to an outgoing mail
message or network news postL. Signature
3.10 A technique in which two different keys are used
for performing encryption and decryption I. Public Key Infrastructure


4. Each statement below has a blank space to fit one of the word(s) or phrase(s) in the list
below. Enter your choice in the “tear-off” answer sheet attached to the question paper,
following instructions therein.                                                                                         (1x10)
A. POP B. Hyperlinks C. CERN D. Hacker E. Client-server computing F. Flame G. Geocities H. Address book I. WAIS J. Filter K. Authentication L. Webmaster M. XBM


4.1 A(n) Address book is a place where you can store the information about the people with whom you correspond.
4.2 CERN is a Swiss organization that developed WWW.
4.3 Geocities is one of the popular free Web presence providers, which helps you to create your
own Website free of cost.
4.4 WAIS is a powerful system for searching and retrieving information from databases
scattered across the Net.
4.5 System administrator for a World Wide Web server is called as L. Webmaster.
4.6 POP is a protocol that is used to retrieve e-mail from a mail server.
4.7 The fundamental relationship of computers on the Net in which one computer acts as a client by
remotely connecting to another computer that acts as a host is called as Client-server computing.
4.8 Authentication is a security feature that allows access to information on an individual basis.
4.9 An inflammatory remark or a message usually associated with e-mail or an article posted to a
newsgroup is referred to as Flame.
4.10 Hacker is a computer user who illegally visits networked computers to look around or cause
harm.

What is Port? List important port numbers?
Answer – Important ports are – 
§  FTP – 21
§  Telnet – 23
§  POP3 – port 110
§  IMAP – port 143
§  SMTP – port 25
§  HTTP – port 80
§  Secure SMTP (SSMTP) – port 465
§  Secure IMAP (IMAP4-SSL) – port 585
§  IMAP4 over SSL (IMAPS) – port 993
§  Secure POP3 (SSL-POP) – port 995
Q15. What are 127.0.0.1 and localhost?
Answer –  127.0.0.1 एक लूपबैक IP address है जिसको की localhost भी कहते है | यह वो IP address or hostname (localhost) है जो की machine खुद को देती है | यह address same machine or computer के साथ IP connection establish करने के लिए use किया जाता है
Q16. Difference between Work-group and a Domain?
Answer- Window network मे domain उन सभी कंप्यूटर्स का एक group है जो की centrally एक server से control होते है  और सभी कंप्यूटर का डेटाबेस सर्वर पर मैनेज होता है | Work-group मे, जब भी  computer आपस मे connected होते है तो कोई एक जगह पर सारे computer का database और authentication manage नहीं होता एंड सभी computer खुद की user account and settings को अपने computer मे locally ही save करके रखते है  
Q18. What is the Windows Registry?
Answer – Window registry जिसको की registry भी कहा जाता है, windows operating system की सभी configuration settings का hierarchical database होता है |
Q19. What is LDAP? Why it is used
Answer – LDAP एक Lightweight Directory Access Protocol होता है | यह active directory की वो protocol है जो की database से data को access करने के लिए काम आती है |
Q20. Define virtualization?
Answer – Virtualization ऐसा environment प्रोवाइड करता है जिसमे एक फिजिकल कंप्यूटर पर अलग अलग OS and configuration (RAM, storage, CPU etc) की मशीन एक साथ चलायी जा सकती है Benefits of virtualization –  
§  Number of फिजिकल सर्वर कम हो जाते है
§  Data center के infrastructure को maintain करना easy होता है

§  Machine को मैनेज करना आसान होता है
§  Productivity एंड performance increase होती है
Q21.  What is HyperV?
Answer -Read here
Q22. What is Virtual Machine
Answer – Read here
Q23. What is domain controller and primary function of the domain controller?
Answer – Domain controller (DC) या network domain controller एक Windows-based computer system है जो की central database मे users की accounts related information maintain करता है | यह windows active directory service मे user authentication, stores user account information एवेम windows domain मे security policies को enforce करने मे भी आता है | Domain controller ही वो entity होती है जो  की system administrators को allow करती है की single username and password से system resources की permission grant or deny कर सके जैसे की printers, documents, folders, network locations, etc | 
What are RJ45 and RJ11 connectors?
Ans: RJ45 connectors LAN/Ethernet connections के लिए एवेम RJ11 connectors Telephone Cable connections के लिए use किये जाते है
What is Windows Server?
Answer – Window server, Microsoft corporation के द्वारा develop किया गया OS है जो की windows client OS के different function को control करने के लिए या manage करने के लिए बनाया गया है जैसे की Windows Server 2012 मे AD, DNS, DHCP, hyperv-replication आदि features होते है जो की डोमेन नेटवर्क मे क्लाइंट को manage करते है

APIPA, Automatic Private IP Addressing का short form है | APIPA windows OS का एक feature है जिसमे की नेटवर्क मे DHCP client machine APIPA के लिए सेल्फ configured होती है किसी भी नेटवर्क मे जब कोई DHCP client मशीन boot होती है तो वो DHCP सर्वर को देखती है जिससे की एक valid नेटवर्क IP एड्रेस मिल सके | लकिन जब DHCP server नहीं मिलता तो विंडोज मशीन APIPA फीचर को use करते हुए एक specified range (जो की रिज़र्व होती है) मे से IP address मशीन को दे देती है

APIPA ranges : APIPA की IP address range है – 169.254.0.1 through 169.254.255.254 with class B subnet mask 255.255.0.0 |  According to Microsoft APIPA service regularly check( every five minutes) DHCP server in network | जैसे ही APIPA को DHCP Server सर्वर मिलता है APIPA सर्विस बंद हो जाती है एवं APIPA address को DHCP सर्वर से मिले हुए IP address से replace कर दिया जाता है

Router vs Modem : आप बहुत बार router and modem के बीच मे confuse होते होंगे क्योकि ये लगभग एक सी दिखने वाली devices है| दोनों का साइज लगभग एक सा होता है, दोनों मे फ्लशिंग लाइट्स होती है एवं दोनों को कम्प्यूटर्स से कनेक्ट किया जा सकता है| लकिन दोनों का फंक्शन बिलकुल अलग है – 

जब किसी भी ISP से इंटरनेट कनेक्शन लिया जाता है तो वो या तो टेलीफोन केबल के जरिये या फिर Ethernet के जरिये कनेक्शन देता है | जब कनेक्शन टेलीफोन केबल के through दिया जाता है तो उसको modem मे लगाना होता है क्योकि modem analog signals को  digital signals मे या digital को analog कन्वर्ट करने का काम करता है | अब इस modem को हमको आगे एक केबल के जरिये router से कनेक्ट करना होता है | router से कनेक्ट करने के बाद, वो router एक से ज्यादा कंप्यूटर को कनेक्ट कर सकता है (according to राऊटर ports and capacity) | 

Router से कनेक्ट होने वाले कंप्यूटर को router DHCP से IP एड्रेस देने के आलावा इंटरनेट से कनेक्ट करने का काम भी करता है| जब किसी कंप्यूटर को router से कनेक्ट किया जाता है तो router उसको एक प्राइवेट IP एड्रेस देता है फिर उसको NAT के जरिये modem से होते हुए इंटरनेट सर्विस प्रोवाइड करता है दोनों मे डिफरेंस इस प्रकार है – 
Modem आपको ISP से टेलीफोन लाइन के (Rj11 port) जरिये इंटरनेट से कनेक्ट करता है जबकि Router एक से ज्यादा कंप्यूटर को same network मे join करने लिए allow करता है
Modem का काम आपके ISP से आये हुए Analog Singal को digital एवं digital को analog signal मे करने का होता है जबकि router का काम modem से मिलने वाली इनफार्मेशन को computers को डिलीवर करने का होता है|  
Modem को एक से ज्यादा कंप्यूटर से नहीं कनेक्ट किया जा सकता जबकि router को एक से ज्यादा कंप्यूटर से कनेक्ट कर सकते है|

DHCP जब एक network का computer start होता है एवं उस कंप्यूटर की DHCP Client service होती है, वो क्लाइंट सर्विस चेक करती है की कंप्यूटर मे static IP address है या computer मे DHCP की setting है| अगर Computer मे DHCP की सेटिंग होती है तो कंप्यूटर DHCP Client service के जरिये DHCP server से IP Address के लिए request करता है| server को जब request मिलती है तो वो उस कंप्यूटर की validity को चेक करने के बाद अपने defined range (scope) and rules के अनुसार एक IP address रिज़र्व करके उस computer को भेज देता है| इस प्रकार उस नेटवर्क computer को IP address मिलता है 
DHCP के फायदे :- 
Reliable IP address configuration – जब किसी network मे DHCP को use किया जाता है तो यह manual IP configuration की तुलना मे IP configuration errors कम करता है जैसे की typographical errors, IP address duplication आदि |
Network administration मे लगने वाला time बचाता है : किसी network मे DHCP configuration करने से system and network administrator के मैन्युअल task को कम करता है | देखिये कैसे
1.       क्योकि यह clients को Centralized and automated TCP/IP configuration करता है |
2.       Clients के IP address को easily schedule time पर update करता है |

Cookies Definition : जब कोई user internet पर किसी वेबसाइट को browse or visit करता है तो website के दवारा एक छोटी सी data file को उस computer पर स्टोर किया जाता है इसको web cookies कहते है | Next time जब भी यूजर वापस उस website को visit करता है तो web browser उस saved cookie को website के server सर्वर पर upload करके user की last activities को बताता है | Cookies को आपकी browsing history एवं other important information याद रखने के लिए ही design किया गया है जैसे की shopping website visit करते समय आपने कौनसे product को shopping cart मे add किया था या आपने गूगल पर कौनसा प्रोडक्ट सर्च किया था ये सभी cookies की help से ही पता चलता है |

वैसे तो cookies बहुत सारे काम करती है लकिन इसका important काम वेबसाइट की login information को store करना भी होता है कुछ website username and password दोनों information save करते है एवं कुछ केवल username | कोई भी cookies मे निचे दिया हुए components होते  है –   

 Handshaking in computer networks
Handshake kya hota hai : Information technology, digital tech fields and telecommunications मे handshaking negotiation का एक automated process है जो की किसी भी channel मे दो entities के बिच मे normal communication start होने से पहले कुछ parameters के साथ set किया जाता है | यह Channel के physical establishment को फॉलो करता है एवं normal information को transfer करता है | Handshaking तब चालू होता है जब एक device दूसरी device को ये indicate करती हुए message करती है की यह connection establish करने के लिए ready है इसके बाद दोनों devices communication channel मे messages भेजती है जो की उनके बिच connection and trust establish करने लिए जरुरी होता है और फिर दोनों डिवाइस communications protocol के लिए agree करते हुए connection के लिए agree करती है
Handshake Process किसी भी communication के rules को establish करने के लिए होता है | जब computer किसी भी दूसरी device से communicate करता है जैसे की modem, printer, or network server तो इसको उस connection मे handshake की जरुरत पड़ती है |
Handshake प्रोसेस मे प्रोटोकॉल इन्वॉल्व होती है एक simple handshake protocol केवल message receiver का काम कर सकती है for example “मुझे आपका last message मिल गया है and मे आगे के आपके message के लिए ready हूँ | आप आगे के message भेज सकते हैजबकि एक complex handshake protocol  का काम ये भी हो सकता  है की sender को receiver से ये पूछने के लिए allow करें की क्या आप message receive  करने के लिए ready है या फिर आपका last message नहीं मिला please resend it” |

O level M@-R4-01-2018

1. A webpage displays a picture. What tag was used to display that picture? (a) pictur (b) Image (c) Img (d) Src 2. <b> tag make...