In 2004, the IAB published RFC3724, "Future of End-to-End." The document reviews the important aspects of "smart endpoints, dumb network," and articulates some perspectives on how Internet engineering was evolving to address those key aspects. Ten years later, evolution has continued -- and the Internet's deployment and evolution are taking new directions in the face of growing awareness of the threat of pervasive monitoring of network traffic. How do we define the end-to-end principle today and is it still an important piece of ensuring a robust, reliable and trusted Internet in 2020? Each of three panelists will present their predictions for the state of one of the three facets (network, endpoints, infrastructure/middle) in 2020, followed by questions and interactive discussion. Panelists are Harald Alvestrand, Fred Baker, and Andrew Sullivan. The Internet Society's Leslie Daigle will moderate.

1. Evolution of end-to-end: why the Internet is not
like any other network
Leslie Daigle, moderator.
Chief Internet Technology Officer
The Internet Society
http://www.internetsociety.org

2. We are…
Not at the IETF
! Taking discussion up a level
! Taking any identified work items to the appropriate IETF WGs
On the air
! Streaming
! Recording
Stopping at 12:45pm so you can all get back to the
IETF…
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3. Agenda outline
Overview of the panel
Panelists’ predictions
Panel discussion
Open mic
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4. Panel overview
http://www.internetsociety.org

5. From the IAB’s RFC3724 (2004)
One of the key architectural guidelines of the Internet
is the end-to-end principle in the papers by Saltzer,
Reed, and Clark [...]. The end-to-end principle was
originally articulated as a question of where best not to
put functions in a communication system.
Yet, in the ensuing years, it has evolved to address
concerns of maintaining openness, increasing reliability
and robustness, and preserving the properties of user
choice and ease of new service development as
discussed by Blumenthal and Clark in [...]; concerns that
were not part of the original articulation of the end-toend principle.”
The Internet Society

6. Current realities
We still want to build an Internet that features:
! “increasing reliability and robustness, and preserving the
properties of user choice and ease of new service development “
Significant challenges to that include
! Business evolution
! Reactions to the revelations of pervasive monitoring
– “Encrypt everything everywhere always”
– Localization of data based on physical geography
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7. At the heart of the matter
[How] Does the end-to-end
principle matter in today’s
Internet and going forward?
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The Internet Society

8. The Panel
Leslie Daigle (Moderator)
Fred Baker – network
Andrew Sullivan – infrastructure
Harald Alvestrand – endpoint
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9. Panelists predictions
http://www.internetsociety.org

10. Fred Baker
Network
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http://www.internetsociety.org

11. End$to$End$principle$
• Mul$ple'statements'in'the'same'paper:'
• “The$principle,$called$the$end2to2end$argument,$suggests$that$
func8ons$placed$at$low$levels$of$a$system$may$be$redundant$or$of$
li=le$value$when$compared$with$the$cost$of$providing$them$at$
that$low$level.”$
– General'statement'of'the'end5to5end'argument'or'principle'
• “The$func8on$in$ques8on$can$completely$and$correctly$be$
implemented$only$with$the$knowledge$and$help$of$the$applica8on$
standing$at$the$end$points$of$the$communica8on$system.$
Therefore,$providing$that$ques8oned$func8on$as$a$feature$of$the$
communica8on$system$itself$is$not$possible.”$
– This'formula$on'applies'in'cases'in'which'end'system'applica$on'
knowledge'and'help'is'required'to'implement'func$onality'

12. The$Stupid$Smart$Predictable$Network$
• My'understanding'of'the'End'to'End'principle:'
– One'could'describe'it'as'a'“principle'of'least'surprise”'or'a'
“plea'for'simplicity”.'
– A"lower"layer"should"do"what"an"upper"layer"expects.""
• Operate'correctly'per'the'protocol'
• Recursive!'
• Second5guessing'layers'above,'and'introducing'state,'creates'
unintended'consequences'for'operators'and'users.'
– Lower'layer'performance'enhancements,'implemented'by'
including'equivalent'func$onality'in'two'layers,'are'explicitly'
allowed;''
• They%should%measurably%enhance%performance…%

13. Examples$of$things$the$predictable$
network$does:$
• When$handed$a$packet$des8ned$to$a$unicast$or$anycast$address,$it$
delivers$the$packet$to$the$address$unchanged$
– It,'however,'intelligently'determines'the'route,'something'the'
applica$on'does'not'do'
– If'it'has'mul$ple'reasonable'routes,'it'uses'them'effec$vely'without'
applica$on'interven$on'
• It$may$route$traffic$in$a$manner$that$enhances$the$opera8on$and$
profit$of$its$administrator$
– Example:'BGP'rou$ng'may'op$mize'the'cost'to'an'administra$on'
– Example:'a'load'balancer'may'balance'load'among'many'hosts'
• It$operates$transparently$
– When'a'predictable'network'does'something'unusual'with'a'session'or'
packet,'it'tells'the'sender'

14. Examples$of$things$the$predictable$network$
does$not$do$
• Behave$contrary$to$predic8on,'and'in'so'doing'cause'a'user'
or'operator'to'have'to'diagnose'its'behavior'
– When'asked,'in'DNS,'for'the'address'of'party'A,'return'the'address'of'
party'B.'
– When'given'a'packet'intended'for'delivery'to'party'A,'deliver'it'to'
another'party'
– When'given'a'packet'containing'a'quantum'of'data,'deliver'a'packet'
containing'an'unintended'quantum'of'data'
• Note$that$intermi=ent$behavior$is$contrary$to$predic8on$
– While'it'may'change'its'behavior'(such'as'a'route),'it'doesn’t'oscillate'

15. The$network$in$2020$
• Simplicity$Principle$
– “Complexity'is'the'primary'mechanism'which'impedes'efficient'
scaling,'and'as'a'result'is'the'primary'driver'of'increases'in'both'capital'
expenditures'(CAPEX)'and'opera$onal'expenditures'(OPEX).”''
– RFC'3439,'quo$ng'Mike'O’Dell'
– Complexity'is'also'an'enemy'to'security'–'more'things'to'analyze'
• I$see$some$operators$moving$in$the$direc8on$of$drama8cally$
simplifying$their$networks$
– Their'arguments'have'to'do'with'reducing'opera$onal'expense'
– IPv4'networks'tend'to'be'more'complex'and'less'predictable''than'
IPv6,'due'to'NAT'
– Drama$c'simplifica$on'leads'to'drama$cally'improved'predictability'
• I$do$not$see$operators,$or$their$vendors,$making$the$network$less$
able$to$deliver$value$either$to$its$users$or$its$administra8ons$

16. Andrew Sullivan
Infrastructure
http://www.internetsociety.org

17. Isn’t this just the network?
Distinguish bits flowing on the wire + basic
routing with everything else
! Infrastructure specialization is unlikely to go
away
!
!
!
!
Capital expenditure & economies of scale
“Core business” concerns
Cattle not pets
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18. A great compromise
“You got it buddy: the large print giveth, and
the small print taketh away” (Tom Waits,
“Step Right Up”)
Infrastructure providers rely on something like
Fred’s “predictable network”
! Infrastructure providers have to alter their
behaviour depending on the user
!
!
They’re all doing this at once
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19. Know your customer in
2020
!
Technologies that give hints will be embraced
!
!
!
!
Identify certain properties of network user
Correlate user across different services
Not very end-to-endy
Technologies that are invasive with be
eschewed
!
!
!
Customers hate intrusion
Corner cases == support costs == no profit
End-to-endy
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20. Wishful thinking
Protocol development provides exactly
enough hint to do good, and not enough to
do harm.
! The cracks in “network neutrality” don’t
become a complete breach.
!
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21. Harald Alvestrand
Endpoint
http://www.internetsociety.org

28. General discussion
http://www.internetsociety.org

29. At the heart of the matter
[How] Does the end-to-end
principle matter in today’s
Internet and going forward?
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The Internet Society