UNTANGLING THE WEBCLASS 1 – INTRODUCTION TO THE COURSE

THE HARDWARE AND PROTOCOLS THAT POWER THE WEBINTERVIEW QUESTION: WHAT HAPPENS WHEN YOU TYPE A URL IN THE

SEARCH BAR?

AGENDA FOR TONIGHT• Intro to the course and instructors• First section

• The hardware that powers the internet• Basic internet protocols

• Second section• Larger networks, load balancing, caching, content delivery networks

• Third section• Web servers and HTTP

• Wrap-up and group time

HIGH LEVEL GOALS

• Introduce you to the web and web software development• Learn how web development teams work together• Understand customers and applications• Start to build a development portfolio

WHAT THIS COURSE IS NOT

• It is not a rigorous introduction to software development• We won’t talk too much about data structures, Big-O notation, memory efficiency

• It is not the end of the road, but just barely a beginning• Academic computer science, bootcamps, practical experience

• It is not a Lean Launchpad style business accelerator• We’ll talk about what you want to do to launch a web business, but I do not expect

the group projects you do in the class to be the basis of that business. If you hit a home run out of the gate, of course, that’s great too! But it is not the goal or expectation.

INSTRUCTOR BIO – DEREK JACOBY

• Recent computer science PhD at Uvic, but in the field since the early 90’s• 10 years at Microsoft, mostly in Microsoft Research working on speech

recognition• Development, user research, program management were all roles I filled

• Singularity University graduate• Focus areas

• Web development• Bioinformatics• Data visualization

INSTRUCTOR BIO – YVONNE COADY

• Full professor at Uvic• Has taught this course twice before• Specialization areas include systems architecture,

containerization, cloud computing, and high capacity networks

• http://webhome.cs.uvic.ca/~ycoady/index.html

COURSE STRUCTURE

• Weekly lecture• 3 hours is a long time, so we’ll break it up with exercises

• Group project• Won’t come up for a couple weeks, but start thinking about groups. • Ideal group size is 3-4, but smaller or a bit larger is fine too.• The project is in 3 parts – defining a website concept, writing a website front-

end, writing a website back-end• Ideal is to stay with the same group for the entire time, but if necessary

switching can occur after week 7 where part 1 is due

GRADING• 11 Individual Exercises (5% each) 55% Due beginning of

class time• 3 Team Projects (15% each) 45% October 17,

November

• Grading SystemF D C C+ B- B

B+ A- A A+0-49 50-59 60-64 65-69 70-72 73-76 77-79 80-84 85-89 90-100

RESOURCES

• CourseSpaces - http://coursespaces.uvic.ca/my/• 20160813940• Will be used for a list of resources, class notes, grades, etc.

• Uvic mailing list• I will use it only for schedule or location changes unless the slack channel below has problems

• Slack – please send me email at derekja@gmail.com with the title “slack access” and I’ll add you

• https://untangling.slack.com/

• Slides• http://www.slideshare.net/derekja

CLASS LOCATION

• When we put this course together we expected primarily non-Uvic folks so downtown made sense. On Sept 14, 21, Oct 5, and Nov 2 and 30th this downtown location is unavailable. Uvic has a nice smart classroom available for us – group tables with computers which can be shared with a central display.

• Option 1: we stay downtown on all other nights where it is available here, go to Uvic for the remainder

• Option 2: we move to Uvic for all the classes

MODULE PREVIEW – WEEKS 1-3

1 What happens when you type a URL in the address bar?  switches and routers  dhcp and IP addresses  firewalls  servers  dns and registrars  cdn's  cloud services

HW: video yourself answering an interview question

2 What happens when someone searches for your website on google?  pagerank  SEO  google analytics

HW: given a website, find 5 things you’d do to boost natural traffic

3 Where can you buy paid advertising and how does it work?  google adwords  facebook  buying clicks and followers  SaaS and PaaS  lifetime value of a customer

HW: decide how to spend your marketing budget

MODULE PREVIEW – WEEKS 4-64 How do you build an HTML page?  Headers and bodies  tags  scripts  Source code control

(project 1 assigned – must have groups formed)

HW: build a personal webpage on github pages

5 javascript  intro to js  es6  editors and assistance

HW: answer some common javascript interview questions

6 UX design and collaboration  user stories  user research  lean methodologies  business model canvas  MVP  hackathons  scrums  agile

HW: create a business model cavas (for any project, can be for group project but must be done individually)

MODULE PREVIEW – WEEKS 7-9

7 Making pages look pretty  CSS  Frameworks - react and bootstrap

Project 1 dueProject 2 assigned

HW: build a simple bootstrap site

8 Where do I host, and how?  Digital ocean  Heroku  AWS  Google  IBM  Azure

HW: no assignment planned for this week

9 Making pages smart  Intro to Bluemix  speech services  chatbots  natural language

HW: build a bluemix website

MODULE PREVIEW – WEEKS 10-12

10 databases and servers  SQL  NoSQL  database services  APIs

Project 3 assigned

HW: create a database on bluemix and use it to populate a web page

11 JSON and communications  RESTful APIs  stateless servers

HW: create a JSON API for a service and show it in use

12 Pitch day!  Giving useful feedback Learn to kill your babies!

Projects 2 and 3 due

HW (turn in by end of class): give 2-3 pieces of constructive critical feedback for each presentation

QUESTIONS ABOUT THE STRUCTURE OF THE COURSE?

TECHNOLOGY STACKS AND A WEB INTRODUCTIONWHEN YOU TYPE A URL INTO THE ADDRESS BAR, WHAT HAPPENS?

LAYERS OF ABSTRACTION – A CONCRETE EXAMPLE

• User interface/end user interaction• Case design, hardware layout• Electronics design – planning circuit boards, component selection• Chip design – creating a microprocessor, memory, ASICs, etc.• Physics and chemistry – how electrons move

LAYERS OF ABSTRACTION – AN ABSTRACT EXAMPLE

• Differential equations• Calculus• Geometry• Algebra• Functions and logic• Counting and arithmetic

LAYERS OF ABSTRACTION IN WEB DEVELOPMENT

Physics and electronics – chip design, circuit boards, etcServers, routers, access points, networking hardware, fibre and other connections

Wire protocols, connection standards, low level networking firmware

TCP/IP, DHCP, DNS, ICMP, UDPHTTP, web servers, streaming protocols, chat protocols, etc. Backend software, databases, microservicesFront-end software, UI frameworks, client hardware

USER NEEDS BUSINES

S MODELS

ADVERTISING SEARCH

ENGINE OPTIMIZATION

USABILITY

INTERACTION MODELS

USER INTERFACE DESIGN

WHAT HAPPENS WHEN YOU TYPE “FACEBOOK.COM” INTO THE ADDRESS BAR• Simple first version

https://www.khanacademy.org/partner-content/code-org/internet-works/v/the-internet-ip-addresses-and-dns

But wait, what are IP addresses? What’s a DNS server?

SHORT BREAK

• Questions?

• Be back in 5!

https://www.youtube.com/watch?v=dE4rsNuG0aw

ROUTERS, SWITCHES, AND HUBS OH MY!

• How does my computer connect to the internet?• First, a wired computer.• Every computer gets an IP address, but not necessarily one

that connects to the general internet.• Let’s first look at how the computers around you connect to

each other

HUBS – THE LEAST INTELLIGENT CONNECTION

Everything is connected to everything elseBut it’s cheap, and easy

SWITCHES – A LITTLE BIT SMARTER

ROUTERS – SMARTER YET• DHCP and NAT

• Dynamic Host Configuration Protocol• Network Address Translation

NAT is also a rudimentary firewall

DHCP – MORE DETAILS

• Every network interface has a MAC address. This is a hardware address (although it can sometimes be overridden in software)

• The MAC address must be unique inside a local address space and is the basis for requests to the DHCP server

• This DHCP request and acknowledge pattern is one we’ll see again

ROUTER CONFIGURATION• Way more than is needed for this course – Quality of Service

(QoS), logging, MAC address filtering, port forwarding, etc.

WIRELESS CLIENTS

• Only a little bit different. A Wi-Fi access point is generally integrated with a router.

• Each access point broadcasts an SSID – Service Set Identifier• There are also more variants of wireless security since

physical access isn’t needed to connect

EXERCISE

• Break up into groups of 5• If we don’t split up evenly, groups may be as large as 7 or as small as 3• Each of you will be playing at least one role

• Client• DHCP• DNS• Router• Web servers

• When you have groups formed, I’ll come hand around game cards

EXERCISE SCENARIOS

• 1: The client requests www.facebook.com• 2: The client requests www.facebook.com/zuck• 3: The client requests www.somemissingwebsite.com

QUESTIONS AND A SHORT BREAK

DEBRIEF ON EXERCISE 1

LARGER NETWORKS

• Routing on the internet• Caching• Load balancing• Anycast• Content delivery networks (CDNs)• Network tools

ROUTING AND RELIABILITY

• We’ve talked about routers in local networks, but they also drive the internet

• https://www.khanacademy.org/partner-content/code-org/internet-works/v/the-internet-packet-routers-and-reliability

PORTS AND PROTOCOLS

• Ports are like a door in an apartment building – arbitrarily assigned but if you knock on the wrong one you’ll never find who you’re looking for

• We’ve talked about TCP/IP but other protocols exist• UDP• ICMP• Multicast• SIP

CACHING

• We’ll talk about headers later• But basically it is largely up to the page whether or not it can

be cached• Other network elements can cache too

LOAD BALANCING

ANYCAST

CONTENT DELIVERY NETWORKS (CDNS)

NETWORK TOOLS

• Complex and expensive tools• IBM Tivoli, Aruba, etc

• Free and easy tools• https://www.whatismyip.com/• Ping, traceroute, etc (local or through nwtools.com)

• Some very powerful tools are also free• Wireshark, https://www.wireshark.org/

NETWORK TOOLS

NETWORK TOOLS EXERCISE

• Go to nwtools.com• Compare the following on ping and traceroute

• google.com• 8.8.8.8• uvic.ca• facebook.com• aport.ru• 127.0.0.1

• What made sense? What was weird?

QUESTIONS

• And a short break

DEBRIEF ON EXERCISE 2

HTTP AND WEB SERVERS• We’ve come right back up to that line I mentioned

Physics and electronics – chip design, circuit boards, etcServers, routers, access points, networking hardware, fibre and other connections

Wire protocols, connection standards, low level networking firmware

TCP/IP, DHCP, DNS, ICMP, UDPHTTP, web servers, streaming protocols, chat protocols, etc. Backend software, databases, microservicesFront-end software, UI frameworks, client hardware

USER NEEDS BUSINES

S MODELS

ADVERTISING SEARCH

ENGINE OPTIMIZATION

USABILITY

INTERACTION MODELS

USER INTERFACE DESIGN

HTML AND HTTP

• https://youtu.be/1K64fWX5z4U?t=61

HTTP PROTOCOL

• Responses are the first thing to think about

WEB SERVERS

• Apache• Nginx• IIS• Flask• Gunicorn• Express

NGINX EXAMPLE

WEB SERVERS• Web servers basically serve up files• Many of those are HTML files, but also media files, text files,

etc.• The HTTP response codes are important, for instance it would

be very easy to configure a particular page with two different entry points, but much better to configure one of them to return a 301 and then serve the page up from only a single location. This is because of the way search engines work. Want to try and find an answer as to why for next week?

3RD EXERCISE

• Break into pairs• Decide who is going to interview first• The first interviewer asks:• from a front-end developer perspective, what happens when

you type facebook.com in the address bar? what about when you misspell it as fcebook.com? how about facebook.com/somemissingpage.htm?

3RD EXERCISE

• Now swap roles• The second interviewer asks:• from a networking perspective, what happens when you type 

facebook.com in the address bar? What if you’re on a wireless computer behind a firewall? Facebook has a CDN, does that change your answer?

WRAP UP

• Student intros• Homework

• Record a video of yourself answering the “what happens when you type facebook.com into the address bar” question. Before answering it describe your ideal web job and how that effects how you answer.

• Create a youtube channel for yourself and add the video, leave it unlisted or public as you prefer (can host elsewhere, or even bring a usb stick to class, if you need to)

• Send the link to Derek at derekja@gmail.com by the start of class on the 12th.

GETTING READY FOR NEXT WEEK• First, make yourself a google account if you don’t already

have one. We’ll use this for google analytics next week.• Second, make a nitrous.io account. This is a free account

which we’ll use for hosting projects.• Third, make a github account. This will be you developer’s

portfolio, so we’ll start populating it!• Finally, please make sure you’ve gotten on the slack channel.

Send me email at derekja@gmail.com to get access.