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W02 / COSC 6590A / Advanced Computer NetworksW02 / COSC 6590A / Advanced Computer NetworksPaper PresentationPaper Presentation

Rethinking the Design of Internet:Rethinking the Design of Internet:The End-to-end Arguments vs. the Brave New WorldThe End-to-end Arguments vs. the Brave New World

Marjory S. BlumenthalMarjory S. BlumenthalComputer Science and Telecoms Board, NRCComputer Science and Telecoms Board, NRC

David D. ClarkDavid D. ClarkMIT Lab for Computer ScienceMIT Lab for Computer Science

Appeared in ACM Transactions on Internet Technology, Vol. 1, No.1 Aug.2001, p70-109Appeared in ACM Transactions on Internet Technology, Vol. 1, No.1 Aug.2001, p70-109

Presented by Yanling WangPresented by Yanling WangComputer Science, York University, TorontoComputer Science, York University, Toronto

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OutlineOutline

• Communications & Internet historiesCommunications & Internet histories• End-to-end argumentsEnd-to-end arguments• New requirements in today’s communicationNew requirements in today’s communication• Identify a range of possible solutions that might be used to Identify a range of possible solutions that might be used to

meet these requirementsmeet these requirements• Look at the implications for the rights and responsibilities of Look at the implications for the rights and responsibilities of

the various parties that comprise the Internetthe various parties that comprise the Internet• Describe the range of emerging playersDescribe the range of emerging players• ConclusionsConclusions• Picture of future InternetPicture of future Internet

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History of CommunicationsHistory of Communications

• 1500's1500's Chief noblemen (e.g. the Pope) possessed more than 100 Chief noblemen (e.g. the Pope) possessed more than 100 messengersmessengers• 15441544 Holey Roman Empire granted monopoly to the Thurn and Tassis family -> D Holey Roman Empire granted monopoly to the Thurn and Tassis family -> D

eutche Bundesposteutche Bundespost• 1840's1840's TelegramTelegram The first digital method of electronic communication The first digital method of electronic communication• 18761876 Bell Bell telephonetelephone developed by accident! AT&T owner of the patent. developed by accident! AT&T owner of the patent.• 18961896 Telephone dialTelephone dial invented by Almon Strowger, a Kansas City undertaker. Fear invented by Almon Strowger, a Kansas City undertaker. Fear

ed he was loosing business to a competitor whose wife happened to be a local switced he was loosing business to a competitor whose wife happened to be a local switchboard operator. First place to use it was La Porte, Indiana. Also developed the 'stehboard operator. First place to use it was La Porte, Indiana. Also developed the 'step' exchange still in use.p' exchange still in use.

• 1890's1890's Loading coil developed to allow Loading coil developed to allow 'long-distance' calls'long-distance' calls..• 1920's1920's Telephone companies started using Strowgers technology as patent ran out.1 Telephone companies started using Strowgers technology as patent ran out.1

920's AT&T developed way of putting many calls on one line (920's AT&T developed way of putting many calls on one line ( 'analogue carrier' tec'analogue carrier' technologyhnology). Continued to be develop up until 1970's). Continued to be develop up until 1970's

• 19621962 First First communications satellitecommunications satellite launched launched• 1970's1970's Fiber opticFiber optic technologytechnology• 1980's1980's Digital technologiesDigital technologies

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History of InternetHistory of Internet(INTERnational NETwork / INTERconnected NETwork)(INTERnational NETwork / INTERconnected NETwork)

1957 Sputnik Launched

1969 ARPnet: in US

1972 ARPnet: Report Generated

1973 ARPnet: Norway & England

1974 Transmission Protocol

1983 TCP/IP

1984 MILNET & DNS

1985 1st Internet Domain

1986 Online Forum & Firewall

1990 ARPnet off, Internet On

1991 Info. Retrieved from Server

1992 Hypertext WWW

1993 Web Browsers Surfing

1994 Size Double/Year

1999 ISPs: Internet Free AccessThe figure was copied from the Internet.

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Internet Design Principles:Internet Design Principles:End-to-end ArgumentsEnd-to-end Arguments

• The function in question can completely and correctly be The function in question can completely and correctly be implemented only with the knowledge and help of the implemented only with the knowledge and help of the application standing at the endpoints of the communications application standing at the endpoints of the communications systems. Therefore, providing that questioned function as a systems. Therefore, providing that questioned function as a feature of the communications systems itself is not possible.feature of the communications systems itself is not possible.– This suggests that specific application level functions usually can not, This suggests that specific application level functions usually can not,

and preferably should not, be built into the lower levels of the system-and preferably should not, be built into the lower levels of the system-the core of the network.the core of the network.

• Result in:Result in:– Function migrates to the end node.Function migrates to the end node.– Network should be “as transparent as technology permits”.Network should be “as transparent as technology permits”.

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A simple View of InternetA simple View of Internet

User

User

Router Router

RouterUser

User

RouterRouter

Router

Router

User

User

User

User

User

The Internet

Router

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Advantages of the End-to-end ArgumentsAdvantages of the End-to-end Arguments

• User empowermentUser empowerment– Run what you pleaseRun what you please

• Flexibility in the face of unknown applicationsFlexibility in the face of unknown applications– A network to glue computers togetherA network to glue computers together

• Lower cost in core of networkLower cost in core of network– Eliminate special featuresEliminate special features– Rely on edge-node equipmentRely on edge-node equipment

• More robust applicationsMore robust applications– No unexpected failures of third party nodesNo unexpected failures of third party nodes

• Moving application specific functions out of the core of the networkMoving application specific functions out of the core of the network– Complexity of the core network reducedComplexity of the core network reduced– Generality in the network increases the chances that a new application can be added without Generality in the network increases the chances that a new application can be added without

having to change the core of the networkhaving to change the core of the network– Applications do not have to depend on the successful implementation and operation of application Applications do not have to depend on the successful implementation and operation of application

specific services in the networkspecific services in the network

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Examples of Emerging Requirements Examples of Emerging Requirements in Today’s Internetin Today’s Internet

• Operation in an untrustworthy worldOperation in an untrustworthy world– Imply more mechanism in the center of the network to enforce “good” Imply more mechanism in the center of the network to enforce “good”

behaviorbehavior• More demanding applications (streaming audio & video, etc.)More demanding applications (streaming audio & video, etc.)

– More sophisticated internet service is needed to assure each data stream a More sophisticated internet service is needed to assure each data stream a specified throughputspecified throughput

• ISP services differentiationISP services differentiation– ISP-specific intermediate serversISP-specific intermediate servers

• The rise of third-party involvementThe rise of third-party involvement• Less sophisticated usersLess sophisticated users

What do these requirements really imply?What do these requirements really imply?– World is becoming more complexWorld is becoming more complex– What is needed is a set of principles that interoperate with each other, some What is needed is a set of principles that interoperate with each other, some

built on the end-to-end model, and some on a new model of network-centered built on the end-to-end model, and some on a new model of network-centered function.function.

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What About in the Brave New World?What About in the Brave New World?

• The End-to-end model does not empower:The End-to-end model does not empower:– ISPs: want to sell services, add value, and make money. ISPs: want to sell services, add value, and make money.

New network services, protection, control of New network services, protection, control of applications/content, accountingapplications/content, accounting

– Rights holdersRights holders– Governments: control of content, taxation, consumer Governments: control of content, taxation, consumer

protection, law enforcementprotection, law enforcement– EmployersEmployers

• It empowers:It empowers:– Only certain application makersOnly certain application makers

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End-to-end Argument FunctionsEnd-to-end Argument Functionsat Network level - “in” the Networkat Network level - “in” the Network

• Adding functions to the core of the networkAdding functions to the core of the network– FirewallsFirewalls

– Traffic filtersTraffic filters

– Network address translation elementsNetwork address translation elements

• Design issues in adding mechanism to the core of the Design issues in adding mechanism to the core of the networknetwork– Imposing a control element into the path of communicationImposing a control element into the path of communication

– Revealing or hiding the content of messageRevealing or hiding the content of message

– Labels on informationLabels on information

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End-to-end Argument FunctionsEnd-to-end Argument Functionsat Application Level - “on” the Networkat Application Level - “on” the Network• Application-level services being employed to augment or Application-level services being employed to augment or

modify application behaviormodify application behavior– Anonymizing message forwarders: It is critical that the user construct Anonymizing message forwarders: It is critical that the user construct

the route, the ISP, or any other third party should not be able to the route, the ISP, or any other third party should not be able to determine the path directly. Third party removes the possible determine the path directly. Third party removes the possible identification in the messages.identification in the messages.

– Helpful content filteringHelpful content filtering– Content cachesContent caches

• More complex application design-using trusted third partiesMore complex application design-using trusted third parties– Public-key certificate: user can create a public key and give it to others, Public-key certificate: user can create a public key and give it to others,

to enable communication with that user in a protected manner. Third to enable communication with that user in a protected manner. Third party issues a public key certificate and manages the stock of such party issues a public key certificate and manages the stock of such certificates.certificates.

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A Complex View of the InternetA Complex View of the Internet

User

User

User

User

User

User

User

The Internet

BackboneISP

BackboneISP

BackboneISP

LittleISP

LittleISP

Campus

Corp

User

User

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Addressing Where We AreAddressing Where We Are• The rise of the new playersThe rise of the new players

– GovernmentsGovernments– ISPsISPs– Industry consolidationIndustry consolidation– Institutional providers of Internet services: corporations, schools, and non-profit Institutional providers of Internet services: corporations, schools, and non-profit

organizationsorganizations– International nature of the InternetInternational nature of the Internet

• The erosion of trustThe erosion of trust– May be most fundamental for transforming the InternetMay be most fundamental for transforming the Internet– Use trusted third partiesUse trusted third parties– Both end-points and third parties may wish to interpose intermediate elements into a Both end-points and third parties may wish to interpose intermediate elements into a

communication to achieve their objectives of verification and controlcommunication to achieve their objectives of verification and control¿¿ But, are third parties actually trustworthy? Or are end-points talking to the But, are third parties actually trustworthy? Or are end-points talking to the third party they think they are?third party they think they are?

• Rights and responsibilitiesRights and responsibilities– The end-to-end design of the Internet gives the user considerable power in determine The end-to-end design of the Internet gives the user considerable power in determine

what applications he/she chooses to usewhat applications he/she chooses to use– Today the Internet places few limits on what groups of consenting end-nodes do in Today the Internet places few limits on what groups of consenting end-nodes do in

communicating across the networkcommunicating across the network ¿¿ How can the desire for privacy and anonymity be balanced against the need for How can the desire for privacy and anonymity be balanced against the need for accountability, given the freedom of action that the end-to-end arguments imply?accountability, given the freedom of action that the end-to-end arguments imply?

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Moving ForwardMoving Forward

• LabelsLabels– A comprise between autonomy and visibility of actionA comprise between autonomy and visibility of action

• Distinction between private and public communicationDistinction between private and public communication– Accept that private communication is not restrictedAccept that private communication is not restricted– Focus on communication to the publicFocus on communication to the public

• New principles for application designNew principles for application design– Do not force an end-node implementationDo not force an end-node implementation– Allow the user to select an alternativeAllow the user to select an alternative– A more sophisticated form of empowermentA more sophisticated form of empowerment

• Tolerance for experimentationTolerance for experimentation

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ConclusionsConclusions

• Elements that Elements that implement functionsimplement functions that are invisible or hostile to end-to- that are invisible or hostile to end-to-end application, in general, end application, in general, have to be “in” the networkhave to be “in” the network

• Multiple forces seem to promote Multiple forces seem to promote changechange within the Internet that within the Internet that may be may be inconsistentinconsistent with the end-to-end argumentswith the end-to-end arguments

• Less work by Less work by consumersconsumers may imply may imply less controlless control over what they can do on over what they can do on the Internet and who can observe what they dothe Internet and who can observe what they do

• Lost of trustLost of trust• Trust can be supported by Trust can be supported by systematic labeling of contentsystematic labeling of content• It is no longer the single creative person in the garage, but the startup with It is no longer the single creative person in the garage, but the startup with

tens of millions of dollars in backing that is doing the tens of millions of dollars in backing that is doing the group innovationgroup innovation• Commercial investmentCommercial investment will will go elsewherego elsewhere, in support of short-term , in support of short-term

opportunities better met by solutions that are not end-to-end, but based on opportunities better met by solutions that are not end-to-end, but based on application-specific servers and services “inside” the networkapplication-specific servers and services “inside” the network

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Picture of Future InternetPicture of Future Internet

• It is possible that we will see, not a sudden change in It is possible that we will see, not a sudden change in the spirit of the Internet, but a slow ossification of the the spirit of the Internet, but a slow ossification of the form and function.form and function.

• In time some new network will appear, perhaps as an In time some new network will appear, perhaps as an overlay on the Internet, which attempts to re-overlay on the Internet, which attempts to re-introduce a context for unfettered innovationintroduce a context for unfettered innovation

• It is premature to predict the final form. What we can It is premature to predict the final form. What we can do is to push in ways that tend toward certain do is to push in ways that tend toward certain outcomesoutcomes

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The End