Network 20 Questions Overview Networked Life: 20 Questions and Answers (M. Chiang, Princeton University) Network 20 Questions Overview Prof. Hongseok Kim Sogang University, EE

Networks everywhere

Facebook network

Twitter network

Wikipedia network

YouTube network

The Internet

P2P network

Access network

Cellular network

Wireless spectrum

Preview trailer You aren’t supposed to understand the next hour.

Q1 What makes CDMA work for my smartphone?

Q2 How does Google sell ad spaces?

Q3 How does Google rank webpages?

Q4 How does Netflix recommend movies?

Q5 When can I trust an average rating on Amazon?

Q6 Why does Wikipedia even work?

Q7 How do I viralize a YouTube video and tip a Groupon deal?

Q8 How do I influence people on Facebook and Twitter?

Q9 Can I really reach anyone in six steps?

Q10 Does the Internet have an Achilles’ heel?

Q11 Why do AT&T and Verizon Wireless charge me $10 a GB?

Q12 How can I pay less for each GB?

Q13 How does traffic get through the Internet?

Q14 Why doesn’t the Internet collapse under congestion?

Q15 How can Skype and BitTorrent be free?

Q16 What’s inside the cloud of iCloud?

Q17 IPTV and Netflix: How can the Internet support video?

Q18 Why is WiFi faster at home than a hotspot?

Q19 Why am I getting only a few % of the advertised 4G speed?

Q20 Is it fair that my neighbor’s iPad downloads faster?

Pedagogical approach Why teach fun in a boring way?

1. Just in time Never delay gratification Never introduce math unless it is used right now

2. Bridge theory and practice No spherical cows or infinite lines Try to avoid random graphs and rational people Still some questions have a big theory-practice gap in their answers

3. Lectures as a network

Methodologies

Bigger pictures Bring engineering to “network science” The importance of domain specific functionalities Bring networking principles to engineering curriculum Modern view of engineering education

Concepts

20 concepts Resource sharing Opinion aggregation and consensus formation Positive network effect Negative network effect Wisdom of crowds Fallacy of crowds Functional hierarchy and layering Spatial hierarchy and overlaying From local actions to global properties Overprovision capacity vs overprovision connectivity

20 concepts Feedback control Utility maximization Protocols Signaling Randomization Graph consistency model Strategic equilibrium Generative models Latent-factor models Axiomatization models

Why take the course? Relevant to your life Intellectually exciting Learn a lot Learn a few things you’ll never forget

Logistics A course about networks and by these networks

Prerequisite and difficulty Linear algebra Multivariable calculus Or…. Only addition and multiplication with some logical thinking

Books

Networks They run your life You’ve got to know them The cool artifacts The mathematical models But also the big ideas