HOW WEB WORKS

Question 1

is a set of rules that partners use when they communicate.

Answer 1

PROTOCOL

Question 2

A set of rules, for routing and addressing packets of data so that they can –across networks
and – at the correct destination.

Answer 2

travel, arrive

Question 3

A suite of communication
protocols used to interconnect
network devices on the internet

Answer 3

Transmission Control
Protocol / Internet
Protocol (TCP/IP)

Question 4

TCP/IP is originally abstracted as a –layer stack.

Answer 4

four

Question 5

(TCP/ IP)Later abstractions subdivide it further into five or – layers

Answer 5

seven

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Transmits raw bit stream over the physical medium

Answer 6

1. PHYSICAL LAYER

Question 7

Defines the format of data on the network

Answer 7

2. DATA LINK LAYER

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Decides which physical path the data will take

Answer 8

3. NETWORK LAYER

Question 9

Transmits data using transmission protocols including TCP and UDP

Answer 9

4. TRANSPORT LAYER

Question 10

Maintains connections and is responsible for controlling ports and sessions

Answer 10

5. SESSION LAYER

Question 11

Ensure that data is in a usable format and is where data encryption occurs

Answer 11

6. PRESENTATION LAYER

Question 12

Human-computer interaction layer, where application can access the network services

Answer 12

7. APPLICATION LAYER

Question 13

INTERNET
PROTOCOLS

Answer 13

APPLICATION LAYER
TRANSPORT LAYER
INTERNET LAYER
LINK LAYER

Question 14

the lowest layer, responsible for both the physical transmission of data/raw bits
across media (both wired and wireless) and establishing logical links.

Answer 14

LINK LAYER

Question 15

Link layer handles –like packet creation, transmission, reception, error
detection, collisions, line sharing, and more.

Answer 15

issues

Question 16

The one term here that is sometimes used in the Internet context is that
of – addresses. These are unique 48- or 64-bit identifiers assigned to network.

Answer 16

MAC (media access control)

Question 17

▪ sometimes also called the IP Layer, routes packets between
communication partners across networks.

Answer 17

INTERNET LAYER

Question 18

Internet layer establishes connection, routing, and –

Answer 18

addressing

Question 19

Internet layer provides “–” communication. It sends out a message to its destination, but expects –, and provides no guarantee the message will arrive intact, or at all

Answer 19

best effort, no reply

Question 20

▪ The Internet uses the – addresses, which are
numeric codes that uniquely identify destinations on the
Internet.

Answer 20

Internet
Protocol (IP)

Question 21

is composed of 32-bit address
length and is the fourth version of
the Internet Protocol (IP).

Answer 21

IPv4

Question 22

is composed of 128-bit
address length and is the latest
updated version of the Internet
Protocol (IP).

Answer 22

IPv6

Question 23

Who Gives an ISP its ISP addresses?

Answer 23

Internet Assigned Numbers Authority (IANA)

Question 24

IANA a department of ICANN,
the Internet Corporation for Assigned Names and Numbers, which is an
internationally organized – responsible for the global coordination of IP addresses, domains, and –.

Answer 24

nonprofit organization, Internet protocols

Question 25

▪ IANA allocates -- from pools of unallocated addresses to Regional Internet Registries, such as AfriNIC (for Africa) or ARIN (for North America) or APNIC (the Asia Pacific Network Information Centre)

Answer 25

IP addresses

Question 26

ensures transmissions arrive in order and without error

Answer 26

The transport layer

Question 27

used by end-user software such as web browsers and email clients.

Answer 27

APPLICATION LAYER

Question 28

Application Layer provides protocols that allow software to -- and -- information and present meaningful data to users.

Answer 28

send , receive

Question 29

Application Layer Protocols

Answer 29

HTTP SSH FTPPOP/IMAP/SMTP DNS

Question 30

is used for web communication

Answer 30

HTTP. The Hypertext Transfer Protocol

Question 31

allows remote command-line connections to servers

Answer 31

SSH. The Secure Shell Protocol

Question 32

is used for transferring files between computers.

Answer 32

FTP. The File Transfer Protocol

Question 33

the Internet's system for mapping alphabetic names to numeric Internet Protocol (IP) addresses like a phone book maps a person's name to a phone number.

Answer 33

Domain Name System

Question 34

Generic top-level domain (gTLD)

Answer 34

Unrestricted Sponsored New

Question 35

TLDs include .com, .net, .org, and .info.

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Unrestricted

Question 36

TLDs including .gov, .mil, .edu, and others. These domains can have requirements for ownership and thus new second-level domains must have permission from the sponsor before acquiring a new address.

Answer 36

Sponsored

Question 37

From January to May of 2012, companies and individuals could submit applications for new TLDs. TLD application results were announced in June 2012, and include a wide range of both contested and single applicant domains. These include corporate ones like .apple, .google, and .macdonalds, and contested ones like .buy, .news, and .music

Answer 37

New

Question 38

These codes are under the control of the countries which they represent, which is why each is administered differently

Answer 38

Country code top-level domain (ccTLD)

Question 39

Some IDNs include --, --, and -- domains (among others) which have test domains at http://παράδειγμα.δoιμή, http:// 例え.テス ト, and http:// ,مثال.إختبارrespectively

Answer 39

Greek, Japanese, and Arabic

Question 40

was the first assigned top-level domain. It is still assigned and used for reverse DNS lookups (i.e., finding the domain name of an IP address)

Answer 40

arpa

Question 41

The owner of a second-level domain can elect to have -- if they so choose, in which case those subdomains are prepended to the base hostname.

Answer 41

subdomains

Question 42

define what application protocols to use

Answer 42

Protocol

Question 43

identifies the server from which we are requesting resources.

Answer 43

Domain

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is a familiar concept to anyone who has ever used a computer file system. The root of a web server corresponds to a folder somewhere on that server

Answer 44

Path

Question 45

They are a critical way of passing information, such as user form input from the client to the server. In URLs, they are encoded as key value pairs delimited by & symbols and preceded by the ? symbol

Answer 45

Query String

Question 46

The components for a query string encoding a -- and password

Answer 46

username

Question 47

The last part of a URL is the optional fragment. This is used as a way of requesting a portion of a page.

Answer 47

Fragment

Question 48

is an application protocol for distributed, collaborative, hypermedia information systems that allows users to communicate data on the World Wide Web.

Answer 48

Hypertext Transfer Protocol (HTTP)

Question 49

are sent in the request from the client and received in the response from the server. These encode the parameters for the HTTP transaction, meaning they define what kind of response the server will send.

Answer 49

Headers

Question 50

Request headers include data about the -- machine (as in your personal computer)

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client

Question 51

The HTTP protocol defines several different types of requests, each with a different intent and characteristics

Answer 51

Request Methods

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one is asking for a resource located at a specified URL to be retrieved

Answer 52

GET request

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This method is normally used to transmit data to the server using an HTML form

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▪ POST request

Question 54

Request Methods

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GET request POST request HEAD request

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is similar to a GET except that the response includes only the header information, and not the body that would be retrieved in a full GET.

Answer 55

HEAD request

Question 56

integer values returned by the server as part of the response header. These codes describe the state of the request, including whether it was successful, had errors, requires permission, and more.

Answer 56

Response Codes

Question 57

response code means that the request was successful

Answer 57

200:OK

Question 58

Tells the client that the requested resource has moved. Codes like this allow search engines to update their databases to reflect the new location of the resource. Normally the new location for that resource is returned in the response.

Answer 58

301: Moved Permanently

Question 59

If the client requested a resource with appropriate Cache-Control headers, the response might say that the resource on the server is no newer than the one in the client cache. A response like this is just a header, since we expect the client to use a cached copy of the resource.

Answer 59

304: Not Modified

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This code is similar to 301, except the redirection should be considered temporary.

Answer 60

2307: Temporary redirect

Question 61

If something about the headers or HTTP request in general is not correctly adhering to HTTP protocol, the 400 response code will inform the client.

Answer 61

400: Bad Request

Question 62

Some web resources are protected and require the user to provide credentials to access the resource. If the client gets a 401 code, the request will have to be resent, and the user will need to provide those credentials.

Answer 62

401: Unauthorized

Question 63

are one of the only ones known to web users. Many browsers will display an HTML page with the 404 code to them when the requested resource was not found.

Answer 63

404: Not found

Question 64

URLs have a length limitation, which varies depending on the server software in place. A 414 response code likely means too much data is likely trying to be submitted via the URL.

Answer 64

414: Request URI too long

Question 65

This error provides almost no information to the client except to say the server has encountered an error.

Answer 65

500: Internal server error