CS1033B: Lecture 5

how many subdomains does the following url have? http://www.abc.def.hij.com

- def is a subdomain of hij.com - abc is a subdomain of def.hij.com SO 2 subdomains in total

how does a domain name work?

- every machine on the internet gets an IP address - a domain name system (DNS) maps the domain name to the correct IP address so data can route to the correct computer

4 reasons not to host your own website

- expensive - continual connection (needs 24/7 high speed internet connection) - technical (setting up all the configurations i.e. mail server) - support (server maintenance requires special skills/knowledge)

how does one connect to the internet?

- internet service provider (ISP) by modem - internet ready cable - digital subscriber line (DSL)

how does the internet work: Internet Protocol (IP)

- like a GPS - picks a route for a packet, stops at routers which pick the next best machine/network to send the packet to - if a communication line is down or broken, it sends the packet back to TCP and TCP chooses a different route

subdomains rules

- max of 127 labels - each label (level) max 63 characters long - but whole domain cannot exceed 255 characters (includes TLD)

domain name rules

- max of 67 characters (including extension) - 0-9 - a-z - dash char (hyphen) - no spaces - cannot start/end with dash - must be one of the approved TLDs

compare pricing for ordering web hosting

- shop around - compare pricing - barter - one year commitment ( vs month by month) - handling fees (for domain name, transferring) - search engine promotion - ask what other services they provide

ISP provides

- user accounts for accessing internet - email access - web space to host/hold your website

top 8 reasons when picking an ISP

- web provider (reliability? how long?) - technical support - disk space - up time (look 99% plus guaranteed) - database/programming language support (needs for dynamic website) - FTP access (unlimited and unrestricted access for easy maintenance) - web statistics summary (traffic on your website, access to your info, control) - scripts availability (counters, forms support)

TLD (top level domains)

.com (commercial organizations) .net (internet administators) .org (non-profit organization) .edu (educational institution) .gov (government agency) .info (information) .biz (business)

Give 3 valid TLDs

.com, .ca, .org

Give an example of a valid IP address

0.0.255.255 (each set bw 0 and 255)

Are the following valid IP addresses? 1.1.1.1 126.265.13.10 129.129.129

1. valid 2. invalid (must be between 0 and 255) 3. invalid, must be 4 sets

each computer has it's own unique

IP address

web hosts

ISP - internet service providers companies that provide space on a server they own for use by their clients as well as providing internet connectivity i.e. Rogers, AOL, etc

web site

a folder containing all the webpages

network

a group of interconnected computers (could be connected with wires, wirelessly, satellites)

how does the internet work: packets

a small group of bytes consisting of a header ad body - header: indicates destination - body: actually contains the message

spring.html

a webpage file

Zack&Cody.Love.You.2.com is a valid domain name. TRUE or FALSE

also false af

eBay is an online

auction site

how does the internet work: circuit switching

two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate

subdomains

used to organize your web server (just like folders and directories organize your computer) - commonly used by organizations that wish to assign a unique name to a particular department function, or service related to the organization

as of 2007, google passes microsoft as the most visited

website in the world

www

world wide web - indicates file is on the world wide web

domain name

www.HOMEWATCHERS.COM

3rd level subdomain

year2005.MYCORVETTES.mycars.com

2nd level subdomain

year2005.mycorvettes.MYCARS.com (min of 3 characters)

TLD (top level domain)

year2005.mycorvettes.mycars.COM

are these the same? ABC.com vs abc.com

yes

cost of domain name

you pay for securing it on a per year basis (registration company, domain extension) - must renew for another year

web server

contains all the web pages for a company or individual (sometimes machine is called a host)

.uwo.ca

domain name - the name of the site - points to web server

the internet is

hardware

to make your website available to the internet community, the website files need to be

hosted on a web server provided by an ISP

http

hypertext transfer protocol - rules that define how data is exchanged between servers and browsers others: ftp://, news://

IP address definition

identifies each computer or device connected to the internet (like a home address) - ex: 192.102.249.3 - consists of 4 numbers with periods in between them - each number ranges from 0 to 255 - not geographical

domain names

identify machines on the internet i.e. a web server machine Julie was here

web server is a

machine host

dotted quad

most popular IP address notation - 4 numbers separated by periods

how does the internet work: Transmission Control Protocol (TCP)

sending: - take a large chunk of data (i.e. webpage, email) and break it into small packets - IP is responsible for sending the packets out to the internet receiving: - detects lost packets, error packets because of network congestion - rearranges and reassembles the packets back into the webpage, email etc

the WWW is

software...that runs on the internet

web pages

stored on the web server machine - just files - usually with .html extension i.e. aboutme.html

domain name

text name corresponding to the numeric IP address of a computer on the internet

why was the internet originally called ARPANET??

the ideas behind the TCP/IP protocol were finded by the Advanced Research Projects Agency (ARPA) of the US Department of Defence (DoD) around 1960 hence the name

web hosting

the service that provides internet users with online systems for storing info, images, video, or any web accessible content

how does data travel?

through a network

True or false, the Internet and the World Wide Web are the same thing?

false (internet - hardware, WWW = software)

The domain name for the url www.homer.simpson.com is homer.simpson.com. TRUE or FALSE

false af

order web hosting

find a company that will hold/host your website (keep the files that make up your website) OR set up your own webserver

website is a

folder

/its/

folder - it is a folder on the web server machine

this process of transferring information is called

packet switching

What is a message (a webpage or an email message or a file) on the Internet broken down into before it is sent over the net?

packets

What are the chunks of data that are sent over the internet called?

packets or datagrams

web development

- choose a domain name - order web hosting - meet with client - create the web site

what is the internet?

- a global system of interconnected computer networks that use the standardized internet protocol suite (TCP/IP) to serve billions of users worldwide - a network of networks

TCP/IP

- a standard Transmission Control Protocol - a set of RULES for the transmission of data

Uniform Resource Locator (URL)

- also known as the website address - every webpage is referred to by a URL - is an address of a web document on a computer - _____

TCP summary

- breaks webpage into package into packets of bytes - figures out IP address of where it wants to send the packets (destination) - figures out source of IP address - IP picks a route for a packet, stopping at routers which pick the next stop (i.e. a router) - packet switching

setting up a website

- choose a domain name - order web hosting - meet with client - begin building the website

customer sophistication

1. customer in driving seat - the internet allows you 2. customers can do their research, without needing to meet sales people as they work down to a short list 3. permission marketing means customers decide who they will listen to and who they will refuse to listen to

choosing a domain name - suggestions

1. keywords - pick a DN with our keywords in it 2.be memorable - descriptive, easy to spell 3. avoid hyphens unless you don't have a choice 4. buy .com first - default extension in people's minds - then try .org, .net, .biz etc (register these as well) 5. keep it short 6. register asap 7. get creative - add e or i or a number in front of a name i.e. isurfing.com or add web or net in front i.e. webcheaptrips.com 8. know the rules of domain names 9. test before buying 10. buy mispelled domains so ppl will still go to your site

eBay was developed in

1995 by Pierre Omidyar - started by a broken laser pointer

True or false, www.csd.uwo.ca/courses is a domain name?

False! domain name is uwo.ca and courses is a folder

who established the URL designation

Tim Berners-Lee

4th level subdomain

YEAR2005.mycorvettes.mycars.com

router

central switching device

webpage is a

file