Quick & Easy steps to download video clips from the Internet
17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system...
Transcript of 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system...
![Page 1: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/1.jpg)
A quick guide to the Internet
David Clark MIT CSAIL
Fall 2011
1
![Page 2: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/2.jpg)
Why should you care? � “People” say: “Why doesn’t the Internet…”
� Protect me from spam. � Control porn � Keep terrorists from plotting � Etc.
� We need to translate from a cry of pain to realistic expectations.
� Must understand (in general terms) the technology to make realistic policy.
2
![Page 3: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/3.jpg)
Defining the Internet � It is not the applications: � Email � Web � VoIP
� It is not the technology � Ethernet � WiFi � Fiber optics
� So what is it?
3
![Page 4: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/4.jpg)
A nice picture A range of applications operating over a range of technologies, by means of a single interface -- the Internet Protocol IP.
IP: the Internet Protocol
Taken from:
Realizing the Information Future: The Internet and Beyond.
Copyright 1994, National Academy of Sciences Reproduced by permission.
Image removed due to copyright restrictions. To view the image, please seehttp://www.nap.edu/openbook/0309050448/gifmid/53.gif
4
![Page 5: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/5.jpg)
What is a network? Or…what is the problem we are solving?
� A shared medium of communications. � Why? � To share expensive resources
� Cannot afford a wire between “everywhere.”
� To facilitate general communication--information sharing.
5
![Page 6: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/6.jpg)
How to share? � Computer traffic is bursty.
� Older sharing method (circuit switching)was inefficient.
� About 45 years ago, the need for a newmode of sharing was felt.
� PACKETS!
6
![Page 7: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/7.jpg)
What is a packet? � Packet:
• Some data with an address on the front. Specified maximum size
• Sent serially across a link.• Use a computer (a ”router” or “packet switch”)
to manage the link.• Statistical sharing.
� A neat idea that has stood the test of time.
7
![Page 8: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/8.jpg)
A simple view of the Internet
User�
User�
User�
User�
User�
User�
User�
User�
Router�
Router�
Router�
Router�
Router�
Router�
Router� Router�
“The Internet”� 8
![Page 9: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/9.jpg)
An (over) simple packet picture
Header Data
Stuff…Destination/Source/Length…stuff
A packet
A packet header
Addresses: written in the form 18.26.0.166
9
![Page 10: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/10.jpg)
What a router does � When it gets a packet: � Check that it is not malformed. � Check that it is not going in circles. � Look at its destination address. � Pick the best link over which to forward it.
� In the background: � Computes the best routes to all destinations.
10
![Page 11: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/11.jpg)
What was at the edge? � The slide said “user”. � It is a “host”, or a “PC”, or a “server”, or a
“computer” or an “end node”. � The place where application code runs. � There might be a person there.
� Get back to this later…
11
![Page 12: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/12.jpg)
Implications � Inside the network there are only packets. � There is no understanding of higher-level
intentions. � The routers have a limited view of what it
means to “operate correctly”. � There is nothing like a “call”, or “placing a
call”, in the router’s design.
12
![Page 13: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/13.jpg)
The service model � The other half of the Internet specification:
� What is the commitment when I send a packet? � Answer: very little. � The Internet tries it best, but makes no
promises. � It can lose, reorder, delay, or duplicate packets. � Usually they arrive in good order. � If they don’t--you have no complaint.
� Called the “best effort” service.
13
![Page 14: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/14.jpg)
Is this such a good idea? � Weak expectation means Internet can run
over “anything”. � Makes the application’s job harder, but not
impossible.
� So, yes, it is a good idea. � But now under attack.
14
![Page 15: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/15.jpg)
Congestion � More than you want to know in one slide… � What happens if too many packets get sent?
� In the short run, queues form in routers. � In the longer run, senders (are supposed to) slow down.
� Why does this work? � Application are expected to tolerate it.
� But if senders do not slow down? � Out of aggression, or because they cannot.
� A raging debate among designers. � And Comcast and BitTorrent…
15
![Page 16: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/16.jpg)
Responses to congestion � Four options. � Demand and expect them to slow down.
� Benign socialist � Police them and punish them if they don’t
slow down. � Police state
� Let them pay to keep going fast. � Capitalist
� Over-provision so net is “never” congested. � Pragmatic
16
![Page 17: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/17.jpg)
What was at the edge? � The slide said “user”. � It is a “host”, or a “PC”, or a “server”, or a
“computer” or an “end node”. � The place where application code runs. � There might be a person there.
17
![Page 18: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/18.jpg)
What a “host” does � Runs the application code � Web, email, voip, ssh, wow, etc.
� Runs software that helps cope with packets and the best effort service model. � Example: Transmission Control Protocol, or
TCP.
18
![Page 19: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/19.jpg)
What is a protocol? � Protocol: A specification of what can be sent
when and in what format.
� A very general term, used to describe manyaspects of networking.• The voltage to represent a 1 or 0 on a link.• The bit sequence to represent characters (e.g. ASCII).• The format of the address on the front of the packet.• How one reports a lost packet.
� From the Greek: "Glued on the front."
19
![Page 20: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/20.jpg)
What does TCP do? � Breaks a chunk of data (what the
application wants to send) into packets atthe sender.
� Numbers the packets. � Keeps sending them until it gets an
acknowledgement. � Puts them in order at the receiver. � Passes the date to the right application. � Provides a very simple failure model.
20
![Page 21: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/21.jpg)
Host vs. router
Internet�
Applications�
Technologies�
TCP� Host knows about�Router
knows about�
NTWT*�
*Not the whole truth� 21
![Page 22: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/22.jpg)
A (less) simple packet picture
Stuff…Destination/Source/Length…stuff
A packet
IP header
Link Dest/Src/Length/NxtHdr SN/NxtHdr (app)
TCP header
Header Data
22
![Page 23: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/23.jpg)
The end-to-end arguments: The lower layers of the network are not the right
place to implement application-specificfunctions. The lower layers of the network should implement basic and general functions,and the applications should be built “above”these functions, at the edges. � E.g. move functions “up and out”.
� This causes function migration to the end-node. � The network should be “as transparent as
technology permits”.
23
![Page 24: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/24.jpg)
Benefits of end-to-end � User empowerment.
� Run what you please. � Flexibility in the face of unknown applications.
� A network to hook computers together. � Lower cost in core of network.
� Eliminate special “features”. � Rely on edge-node equipment.
� More robust applications. � No unexpected failures of third-party nodes.
� An example of “getting it wrong”: make thenetwork reliable.
24
![Page 25: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/25.jpg)
Summary � What “the Internet” does is very simple:
� If forwards packets. � It is oblivious to the purpose of the packets. � Packets allow effective/efficient sharing.
� Lots of applications run on the Internet � And there will be more tomorrow. � Each has its own design. � There is a tension/tradeoff as to where functions are
placed. � The Internet can exploit lots of technologies.
25
![Page 26: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/26.jpg)
How about the phone system? � How does it different from the Internet? � And why?
� What are the implications for policy?
26
![Page 27: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/27.jpg)
A simple view of the Internet
User�
User�
User�
User�
User�
User�
User�
User�
Router�
Router�
Router�
Router�
Router�
Router�
Router� Router�
“The Internet”� 27
![Page 28: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/28.jpg)
A simple view of the phone system
Phone�
Phone�
Phone�
Phone�
Phone�
Phone�
Phone�
Switch�
Switch�
Switch�
Switch�
Switch�
Switch�
Switch� Switch�
“The phone system”�
Phone�
28
![Page 29: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/29.jpg)
The differences? � Switches are powerful, because phones
are simple. � The knowledge of what the phone system is
for is embedded in the switches. � It “knows” that its purpose is to carry voice.
� Routers are simple, because end-points are powerful. � The knowledge of what the Internet is for is
embedded in the end-points.
29
![Page 30: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/30.jpg)
And…? � The phone system has no open API. � No easy way to attach new applications. � Compare the generality of a voice circuit and
packet carriage. � Very different view of layering. There is no
“voice” layer.
30
![Page 31: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/31.jpg)
Multiple views of system � Topology view: � Routers as expression of physical distribution.
� Layered view: � What is the role of each “box”. � What does this imply about limits to action?
� Administrative view. � Who owns/operates each part? � Who controls what talks to what?
31
![Page 32: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/32.jpg)
A more realistic picture
Backbone� (big ISP)�
Backbone� (big ISP)�
Backbone� (big ISP)�
Little� ISP�
User�
User�
User�
User�
Little� ISP�
Corp�
Campus�
Little� ISP�
User�
User�
User�
User�
User�
User�
User�
The ISP lives here..
The ISP does not live at the end-points.
32
![Page 33: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/33.jpg)
What is missing from all this? � What is it for? � How is the Internet used?
� Briefly, lets talk about applications.
33
![Page 34: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/34.jpg)
Application design � Applications run “on” the Internet. They are not
the Internet. � Many approaches to construction
� Patterns of communication. � Use of end node software and server software.
� Modern apps do not follow a simple end to endmodel. � (End to end at application level)
� Remember the end to end argument?
� They are full of servers and services run by thirdparties.
34
![Page 35: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/35.jpg)
Some examples: Email:�
Sender� Server� Server� Receiver�
Web:�
Browser� Proxy� Server�
SMTP� SMTP� POP/ IMAP�
HTTP�
35
![Page 36: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/36.jpg)
More examples: Napster (early peer to peer)� BitTorrent calls the catalog a tracker…�
Peer�
Peer�
Peer�
Peer�
Data� Data�
Data�
Catalog�
36
![Page 37: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/37.jpg)
More examples: Later peer to peer� BitTorrent has a version that works without a tracker, using a distributed data base to try to find the content.�
Peer�
Peer�
Peer�
Peer�
Data� Data�
Data�
Just go feel around for the data. It might be there somewhere.�
37
![Page 38: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/38.jpg)
More examples: Games (some), and IM (some)�
Client�
Client�
Client�
Client� Server�
38
![Page 39: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/39.jpg)
The changing structure… � In the old days, there were two sorts of
devices: � Routers � End-node computers.
� Now: � Server farms � Cloud computing (latest buzzword…)
� So where should computing be placed? � And why?
39
![Page 40: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/40.jpg)
What problems are we solving? � Ease of use � Ease of deployment � Performance � Economic (industry) structure � Robustness � Security � Who is in control? � Function placement based on trust.
40
![Page 41: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/41.jpg)
Trust relationships Email:�
Sender� Server� Server� Receiver�
Web:�
Browser� Proxy� Server�
SMTP� SMTP� POP/ IMAP�
HTTP�
41
![Page 42: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/42.jpg)
Placement of computation � “The Internet” is not changed by where
computation is placed. � Except that we need some really high-
capacity circuits… � But the user and the application is strongly
influenced.
42
![Page 43: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/43.jpg)
I mentioned Comcast… � How did they disable BitTorrent? � They “peeked” at the data part of the
packet � Called Deep Packet Inspection, or DPI.
� When they saw a BitTorrent connection, they inserted an extra message into the flow of packets (some might say “forged”) that said “abort the connection”.
43
![Page 44: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/44.jpg)
What could the app do? � How could an application designer prevent this
sort of intervention? � Encrypt the packets.
� All anyone can see (unless they have the encryption key) is the header.
� Questions for later: � Should application designers and ISPs be in an arms
race? � Should the user view his ISP as an enemy?
44
![Page 45: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/45.jpg)
Host vs. router
Internet�
Applications�
Technologies�
TCP� Host knows about�Router
knows about�
NTWT*�
*Not the whole truth� 45
![Page 46: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/46.jpg)
A (less) simple packet picture
Stuff…Destination/Source/Length…stuff
A packet
IP header
Link Dest/Src/Length/NxtHdr SN/NxtHdr (app)
TCP header
Header Data
46
![Page 47: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/47.jpg)
Implications � Applications are the reason to have an Internet
in the first place. � Only geeks send packets for the fun of it.
� Applications are where the value is generated,and money is to be made. � Ecommerce, advertising, etc.
� Applications greatly broaden the set ofstakeholders. � Porn, music sharing, VoIP…
� Routers “just” forward packets. � Is this the right view?
47
![Page 48: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/48.jpg)
A layered model of cyberspace � The previous discussion suggests that we
can describe the Internet (and cyberspace more generally) using a layered model. � A layered model is a classic way of Computer
Science thinking. � Several layered models have been posed,
including the formal OSI reference model. � We will use a 4 layer model in our future
discussions.
48
![Page 49: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/49.jpg)
A layered model of cyber-space Lo
gica
l
Physical
Application
Internet
Services
Information
Web, etc
DNS
TCP/IP
Ethernet Optical fiber
People
Capital intensive Physically localized
Highly plastic Recursive
Strong boundaries.
Unregulated and diverse Low cost distribution
Blogs, Youtube, Wikipedia, etc.
The net Individuals
groups, govts. Global, diverse, balance
of empowerments
49
![Page 50: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/50.jpg)
Cyberspace itself Lo
gica
l
Physical
Application
Internet
Services
Information
Web, etc
DNS
IP
Ethernet Optical fiber
People
Blogs, Youtube, Wikipedia, etc.
Individuals groups, govts.
The net
50
![Page 51: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/51.jpg)
Now add in the relevant actors. � We will emphasize the importance of
cataloging actors, their objectives, their interactions, the tools of interaction, and the outcomes. � Which actors are successful in shaping
cyberspace and its context, and by what means?
� To test our approach: case studies of actors and their interactions.
51
![Page 52: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/52.jpg)
Providers of service and content Lo
gica
l
Physical
Application
Internet
Services
Information
People
ISPs: Comcast, Level 3 MIT, etc
Hotels, Hot-spots
Akamai
The net Providers
Google, Hollywood, us…
Fiber: SEACOM
52
![Page 53: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/53.jpg)
Equipment/technology Lo
gica
l
Physical
Application
Internet
Services
Information
People
Routers: Cisco, Huawei
Server hardware
The net Providers Suppliers
Data centers, Cloud providers
Fiber: Corning
53
![Page 54: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/54.jpg)
Governance (intl) Lo
gica
l
Physical
Application
Internet
Services
Information
People
Providers The net Suppliers
W3C
IETF
IEEE
Standards
ITU
ITU WSIS IGF
Intl policy
NANOG
ICANN
54
![Page 55: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/55.jpg)
Governments Lo
gica
l
Physical
Application
Internet
Services
Information
People
Providers
The net
SuppliersStandards Govts Intl
policy
55
![Page 56: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/56.jpg)
Users L
ogic
al �
Physical
Application
Internet
Services
Information
People
Businesses CitizensNGOs, etc. Illegitimates The net
Providers SuppliersStandards Intl policy Govts
56
![Page 57: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/57.jpg)
Action: providers Lo
gica
l
Physical
Application
Internet
Services
Information
People Providers
The net�
Suppliers Standards Govts
Money: While all providers purchase equipment to make
Design requirements
Influence: lobby, filings, etc.
Advertising s
Collaboration with the law.
Strategic alliance,
partnership; discriminatory
negotiation
Intl
policy
cyberspace, lower layers are capital intensive.
Businesse Citizens NGOs, etc. Illegitimates
57
![Page 58: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/58.jpg)
Action: legitimate users Lo
gica
l
Physical
Application
Internet
Services
Information
People Providers
The net
Suppliers Standards
Govts
Businesses
Citizens NGOs, etc. Illegitimates
Competitive purchasing
Demand, usage
Complaint
Advocacy
Corporate influence
Intl policy
58
![Page 59: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/59.jpg)
Action: government Lo
gica
l
Physical
Application
Internet
Services
Information
People Providers
The net
SuppliersStandards Govts
Businesse s
CitizensNGOs, etc. Illegitimates
Direct participation,
research funding
Law enforcement
Participation, soft power,
institutional design
Regulation
Purchasing, FIPS
Intl policy
59
![Page 60: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/60.jpg)
Case studies � These three “influence pictures” are
somewhat anecdotal. � As part of research, need to provide
robust grounding. � What tools are used? � Which are effective? � What are the range of motivations.
60
![Page 61: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/61.jpg)
Interactions � If we drew all the arrows from all the case
studies: � The picture would be impossible to
understand. � It would emphasize the dynamic nature of the
interactions. � Many cycles among the actors.
61
![Page 62: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/62.jpg)
Sharing at the different levels Lo
gica
l
Physical
Application
Internet
Services
Information
Web, etc
DNS
TCP/IP
Ethernet Optical fiber
People
Sharing of physical assets reduces costs.
Sharing of common standards provides
interoperation.
Sharing of information is “what its all about”.
Blogs, Youtube, Wikipedia, etc.
The net Individuals
groups, govts. What are implications of the shared experience?
62
![Page 63: 17.447 Lecture 3: Quick Guide to the Internet · A quick guide to the Internet ... The phone system has no open API. No easy way to attach new applications. Compare the generality](https://reader030.fdocuments.net/reader030/viewer/2022040608/5ec45985fc57691b8e20a137/html5/thumbnails/63.jpg)
MIT OpenCourseWarehttp://ocw.mit.edu
17.447 / 17.448 Cyberpolitics in International Relations: Theory, Methods, PolicyFall 2011
For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.
63