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hi I'm Jim carossa I'm a professor at the University of Massachusetts at Amherst and I've been challenged to describe the internet in five levels of increasing difficulty the internet is the most technically complex system that
Humanity has ever built the internet is a network of networks it's a platform on which all of the internet applications that you've heard of can be built
hi it's really really nice to meet you what's your name my name is Skyler Skyler we're here to talk about the internet and I bet you must use the internet a lot right yeah what's your conception about what the internet is the internet for me it's just something
to use when I need like to search up something or right watch videos the internet is physically these computers that all talk to each other billions of computers in the case of the internet
the internet allows us to do a lot of really really interesting what we call applications you ever think about how that video gets to you over the Internet yeah I have no idea got a favorite movie
Matilda Matilda all right we're going to actually build an internet I've got couple of things here that I want to show you or a couple of toys actually okay let's pretend that these round balls are computers and the internet is
something that connects them and right now the Internet is just one communication link and Matilda is sent over the internet from this computer to your computer so
the internet is a network for carrying information from one computer to another now this network here looks pretty simple doesn't it right it's just one thing should we add some more friends in yeah let's say we want to get a video
from here over to here how do you think that video would sort of travel through this network uh maybe I could go to here to here to here to here that's right so that's pretty cool
there are actually lots of different ways to actually go through the internet to get from what we call a source the place that's sending the information to
the receiver the place that's actually Gathering the information together and that's something we actually call routing huh but wouldn't it just be different for it to go from here to here instead of going from here to here to
here to here yeah so that that's a really good observation in most pieces of the internet that's exactly what would happen we want to take sort of what's called a shortest path but still there are multiple paths and why do you
think that might be valuable maybe one way is like messed up or broken so you don't know why exactly so Skyler that was a great discussion about what we just built and I wanted to talk to you about or ask you
about maybe one other really important part about networks and it's not so much the thing itself the physical thing but more about the rules about communication
that's governed by something that are called Protocols are you up for one yeah knock knock who's there lettuce lettuce who let us go on a knock knock joke is an example of a
protocol right the computer that you're using say makes a request you ask for something you get something in return in the internet there are protocols everywhere so that two computers that have never talked to each other before
know the rules for talking to each other this Global Internet with billions of people using it are just lots of smaller networks that are all hooked together to each other but also what the internet
allows are all of these what we call applications Zoom video playing Services can all run on top of the same internet yeah so there's one internet fall mom
exactly there's one internet and lots and lots and lots of things that you can do on top of it foreign well we're going to be talking about computers here today we're going to be
talking about the internet I always like to think of the Internet by analogy to say Road systems for example where you have you know roads in your neighborhood you have state roads you have the interstate highway system and so the
internet is a lot like that it's an interconnection of local roads local networks like the network in your house for example how does like all of the um networks in my house connect to all the
city networks that's good wow great question often it's a little blue wire called an Ethernet cable so that cable is able to bring bits of information up into your apartment at say a billion
bits per second that's pretty fast right literally a wire that goes between a box in your apartment sometimes called a router or a modem in your apartment that comes from an internet service provider
come into this first Network and then that now Network connects to another Network connects to another Network connects to another Network you can face some FaceTime somebody who's like in Australia you can talk to them at the
same time and like you're reaching the same signal so how is it that it gets there so fast we could talk about that by analogy to a road system it's not just one big super highway it's a lot of
smaller super highways that are all interconnected and those interchangers are what are called routers that's where the Links come together we're talking about talking to a friend in Australia so oh it's coming in from the east coast of the United States to this router and
it's going out say that routers in San Francisco it's going out on an underseized cable over to Australia rather than in this direction up to Japan so there is a undersized cable the underseased cables are so cool they're
these big cables that are laid down by switches they cross both the Atlantic the Pacific the Indian Ocean so the underseased cables are how the networks in Europe the United States Asia are are
all connected together how do you connect like wirelessly that's really what we call the first hop it's like from your phone from your tablet from the computer that you're on there's no cables coming in you go over a wireless
connection Wi-Fi is the protocol that allows your computer to talk to that first top router over a wireless communication link and I was wondering like how there's so many different movies or TV shows that you can download
and that they're all there and like if you just play it it just knows what to play they're all in one spot ah you said they're all in one spot in fact they're in lots of spots in Netflix and so most
applications would like to connect you with a server that's close to you server is really just a big computer with a lot of memory a lot of disks that store all the Netflix movies and also so that you
don't have to cross over too many internet links to get from where the server is to the TV or the device in your home so when I'm watching Vampire Diaries in my house how does it know exactly what to do without getting
scrambled up ah another great question there's a couple of things that could happen inside the internet information is sent in these little packets of information from the Netflix server to your your display device and literally
each packet that arrives says this is the first package for Jenna this is the second this is the third this is the fifth this is the fourth and they're reordered for you as a matter of fact your computer will say using the TCP
protocol to the server hey I didn't get packet four can you resend it again and again the Netflix server is very happy to send you packet four again the other is the Internet Protocol if you think about sending letters through the US
Postal Service how you've got an address on it so every packet that flows from the Netflix server to you has an address on it says this is going to Jenna it's going to the What's called the Internet Protocol address of your device think of
all the the range of devices that are hooked up to the Internet it's totally amazing right every single one of them has one thing in common and that is they speak the IP protocol the Internet Protocol that was a great question
so tell me a little bit about yourself I am a senior at New York University I study computer science have you taken any courses on the Internet or studied it at all I've taken applied internet technology so we've talked about
back-end slash front-end Frameworks and libraries things like that okay um so really at the application Level at the application Level for sure I want to ask you a little bit about what you know about the history of the internet have
you heard of arpanet for example I have not heard of arpanet okay back into the 1960s there was a research agency in the United States called DARPA the defense Advanced research projects agency
actually was called arpa at the time they wanted to build this notion of a packet switching network not a circuit switch Network like a phone network where you get a dedicated path and a dedicated set of bandwidth and links
from source to destination so what would package switching enable I'm sure there's something big here for sure there's there's a lot big right and so remember this was a Department of Defense was they wanted to have forms of
communication that were very robust that were survivable right packets could all find their own ways be routed differently through the network so if parts of the network failed you could Route Around failures sounds like uh the
reason for like a request response type of yeah uh structure so you can sort of see how the network architecture that wasn't designed to be 100 reliable inside the
core of the network and had that complexity built into the edges of the network and to me the really cool thing is you you put this infrastructure in place and then all these Super Creative
people think about amazing things to build on top of it and you see this proliferation of amazing applications abstraction I think it's the reason why everything spoken like a real computer
scientist right you're a computer scientist I'm a computer scientist we talk about apis application programming interfaces right the API for the internet is something called a socket right and a socket simply says I can
communicate if I know your internet address you know 128.119.40.186 right that number is the IP address of my server the University of Massachusetts if you know that you
can write a program anywhere in the world and send a message and it'll pop out at my end right I will be remembered during that I've heard that there are like seven keys to the internet
something like that okay well I don't know about the number seven but there's something in the internet that's sort of similar to that it's called the domain name system the dns's role is to
translate names like gaia.cs.ums.edu or ibm.com or facebook.com to an IP address so that your application can actually send a message to that name to that named
service this whatever quantity of people is is able to have some form of control so that's a great question who do you think controls the internet I'm pretty sure the internet is fairly decentralized okay what does that mean
no one Authority holds control over any sort of decisions or destinations so that's that's 98 true right and if you
own a network work like your att.com or your verizon.com you can do within that Network you can do what you want right so in that sense the internet is very decentralized that the control of the
network is up to whoever owns the network the two percent where you said there's nobody in control there's a little bit of centralized control there's an organization called the internet Corporation for assigned names
and numbers its responsibility is to handle as the name I can suggests names and numbers it's that little bit of centralization central Authority that you need when can we see the next
tenfold increase in in Wi-Fi speed you know in terms of tenfold speeds of increases depending on what device you're using right now it's available all you need to do is upgrade right so there's the Wi-Fi protocol is called
802.11 and this is sometimes a source of confusion for people how can it be that I've got a connection at 100 megabits per second from our our TV into our router 100 megabits per second not
enough package dropping where do they get dropped do you think somewhere in their travel process exactly right and maybe they're dropped in your apartment but much more likely they're dropped because of congestion
somewhere between the Hulu or the Netflix or the Disney server if you're watching a video and you're home so even though you've got 200 megabits per second on that last hop you don't have 200 megabits per second
from the server into your into your apartment I see I'm curious as our conversation sort of changed your view or sort of taught you new things about the internet I think that I've sort of
realized that it's a the internet is a technology that's dependent upon so many other factors some more in our control some less tell us a little bit about yourself I'm Casper lant I'm a PhD student at
Columbia University under Henning Schultz tutelage oh good pronunciation thank you I'm interested in networking iot and sort of what kind of data science you can use with the data sets
that you get from such devices one of the things that I designed before starting my PhD with heading was a iot pill dispenser essentially which which pairs with your smartphone which does facial detection and other computer
vision controls and can basically tell who's taking some sensitive medication and make sure that they've taken it correctly we have these low power devices they're sort of at the edge is it just connecting them in across a
wireless device across a wireless link is that the primary challenge or well I think the primary challenge is that for sure but then an additional challenge is keeping everything configured in the way that you expect it to be configured so
for example most iot devices require you when you're configuring them to for you to enter some kind of captive login portal where you connect to a local network that the iot device produces and
then you can input your Wi-Fi SSID and password but then say if you were to change the password or the name of your Wi-Fi network or you move to a new place then suddenly everything needs to be reconfigured right because that's a
problem that scales linearly right that you don't want the complexity of managing them to go up linearly with that you'd like it to still print stay pretty flat as you start adding right exactly I mean the good thing about iot
devices is that they tend to transmit very very small amounts of data we're used to ethernet cables that can handle many hundreds of gigabits per second over a wired device what are the typical data rates iot devices I mean not
hundreds of gigabits no I mean I would imagine upper bound kb per second lower bound you could see bytes per second just on average but I mean say that you have a temperature sensor running off of
your Arduino that's reporting that temperature in your house every minute that's going to be far less than kilowatts per second on average my cinch is you're you're spot on but they'll produce over time a lot of data and that
a lot of iot is about Computing on that data that computation happened mostly at the edge or somehow a combination between the edge and something happening in a far away data center well my sense is right now that all that data tends to
be centralized because iot devices are usually the commercial products of companies do you think they'll share it not without some persuasion but I I agree that these data have massive massive research value something I'm
interested in with my research is collaborating with people who manage these distributed sensor devices and then taking advantage of those data sets and comparing them to say say you were
interested in doing a research project on how daily rush hour traffic impacts the acoustic landscape of New York City figuring out look this Street next to this school is causing decibel ratings
above what we mandate and so there needs to be an intervention here I think for a long time the internet hasn't grappled with but now has with iot and also with cellular networks generally is the question of Mobility do you imagine in
the future that it might be possible for mobile devices not to always have to connect through the same provider to go from one network to another definitely I mean we're already seeing long-range networks like Laura that can first of
all provide access over a much larger coverage area but then also look the same because they're set up to the same specification regardless of where the individual Gateway is so hey Jen it's great to see you again
good to see you Jim we're in level five now so you're the expert expert I'm a huge fan of the work that you did in RCP the routing control platform being a precursor to software-defined networking
and the notion that rather than having protocols actually always compute things that we could compute things in data centers I'd be interested if you could sort of just reflect back on that time and sort of the beginnings of sdn
and where it's come since then yeah and when we were at ATT the thing we found was frustrating is at T would buy routers and they would come pre-baked with a set of protocols a set of knobs that you could turn if you wanted to
influence how the traffic flowed and a set of dials you could read to understand what was going on inside the network right you couldn't directly do what you wanted to do exactly and so we started thinking about earlier work that was done in the telephony network the
old telephone Network and there they had the same problem and they had the idea of having a computer running a program tell a distributed set of telephony switches what to do but the idea was like wow it was kind of a revelation like what would that look like if we did
that not for the whole internet but at least att's part of the internet so in other words use software instead of distributive protocols to tell the network what to do yeah do you see the softwareization of the internet as a
whole happening so so far it hasn't very much I mean basically software-defined networking exists let's say within a single provider backbone or single Cloud providers Network or a single campus there's been some work on doing it at
the juncture points between a pair of networks but one other Trend that's happening that makes it more possible is it used to be that to get from one end to the internet to the other do you have access networks getting much closer to
say Google or Microsoft or other large Cloud providers where even you might only go through two networks right so some people have called that the flattening of the internet right so I think it used to be on average you would go through 10 different networks to get
from a source to a destination exactly and if you take that even further there's starting to be more Edge Computing where you might imagine you might have a cell tower connected to a small number of routers connected directly to a server that's going to be running the application in that case the
entire infrastructure might be controlled by a single party it's totally fascinating to me that we have such an important Global infrastructure and yet the laws that that govern it
tend to be very very local there are tens of thousands of separately administered networks and of course in hundreds of countries and the fact that it even holds together at all is kind of a miracle right well it holds together because we have standards and we have
protocols exactly protocol standards for how the equipment talks to one another and increasingly certificate authorities that help bootstrap the secure encrypted and communication between end hosts so there are a few of these sort of
centrally kind of agreed upon kinds of infrastructure but for the most part each network runs itself and certainly we've heard about some countries that impose firewalls that don't let certain kinds of traffic out or certain kinds of
traffic uh in so there's no Global body that is regulating that not really because each country really can have its own laws its own norms and so they can decide like the great firewall of China can decide they don't want to let
certain content be accessed by the citizens inside that country so if a country decides they don't want to answer requests for a particular domain name they say hey I don't want to let someone know the IP address of this website they can decide not to let those answers be delivered inside their
country and so encryption plays a role in in helping people you know keep their privacy or prevent surveillance but it's not perfect right it's often possible still to to know a fair amount of what people about what people are doing even
if you can't look inside the envelope at the letter that's right right I mean even you could just tell that two people are communicating even though the traffic itself is encrypted so you don't know what they're saying just even knowing two devices are communicating
exactly and in fact if you look at say the sizes of the transfers that they're doing you may know hey I'm talking to Netflix and by the way this is the the length of the movie I watched and right this is the second confirm or guess a
lot of things exactly you're one of the most awesome networking researchers that I know I'm curious just to pick your brain what do you think are some of the Hot Topics in networking research where do you think the field is heading yeah I'm excited about the convergence of
Wireless Communications you know cellular networks Wi-Fi with networking and cloud computing and in particular we're seeing in in Edge Computing a convergence of all three or you might have a mobile phone or a drone or some
other kind of device connecting over the wireless medium directly to a network that connects you directly to the server that might run your application so you want the computation close to where the where the end point is exactly and I
think that what what's now exciting about that is all three of these Technologies Wireless networking and Cloud which are normally three different communities three different sets of Technologies through different sets of Standards or practices now have to work
together in close close harmony to be able to serve as applications that are really critical and that might be interacting with the physical world in ways where safety is is a potential concern you know we've had cellular
networks now for for 20 30 years so when we hear about 5G what's trumpeted the most is the fact that oh super high bandwidth right but I sense that the exciting things are more than just the
network being faster I agree it's both the high bandwidth it's the low DeLay So that you can have these applications that interact with the physical world and need answers in real time it's about having the compute really close so that
you can integrate computation and communication it's about having more coverage coming back again to the softwareization sdn and softwareization is a maybe a little bit behind the
covers that you wouldn't normally see it as a user going from 3G to 4G to 5G you just see an increase in speed but yet the way the network is now being managed again I think is bringing the cellular
networking World sort of into the internet World in terms of the softwareization completely agree management and I think the bringing in of compute and storage is important too I think when you think just about networking it really is often just one
part of the it they know the information technology ecosystem as there's often compute and storage as well and so I think now there's an opportunity to have all of those parts of the infrastructure work together towards an even higher
level goal and so I think it's a really exciting time to to be in the field because now the plumbing is getting close to the application in a way that it wasn't wasn't before [Music] so I really hope you've enjoyed this
video and I hope you've also understood the internet is part of the worldwide Global Communication fabric it's absolutely fascinating how it works
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