i-1 Internet Intro
Taekyoung [email protected]
Internet Background
• Era of Cold War– Sputnik in 1957 -> ARPA, NASA
• Government sponsored goal– Department of Defense (DoD)
• To maintain communication via computers even with threat of war– No central authority– Designed to operate while some systems
are broken2
Another motivation• Naïve researchers
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ARPA -> Defense Advanced Research Projects Agency (DARPA)
Paradigm shift
• Circuit switching → Packet Switching– data to be transmitted is divided into
small packets of information and labeled to identify the sender and recipient
– sent over a network and then reassembled at their destination
– if any packet did not arrive or was not intact, original sender is requested to resend the packet
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Context
• When Packet Switching was proposed– Packet Switching is a new idea
• telco gave it a -5 on a scale of 1-10
– Computers are million dollar items and ARPA can’t buy new ones every year but minicomputers have just arrived
– Time-sharing and inter-process communication are new ideas
– Personal Computers don’t exist– Networks are expensive
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The Internet is born in 1969
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• Enable sharing of supercomputer power
• 4 nodes– UCLA– Stanford (SRI)– UC Santa Barbara– U of Utah
• Including BBN, some say 5 nodes
Zoom in to UCLA
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Interface Message Processor
1972: Robert Kahn
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2000s: middle-age
• Now it faces problems
9
IP
TCP UDP
Applications
token
radio, copper, fiber
802.11 PPPEth
IP “hourglass”
IP
TCP UDP
Applications
token
radio, copper, fiber
802.11 PPPEth
diffserv
intservmcastmobile
NAT IPSEC
Expanding waist?
Internet standardization• Protocol: a set of rules governing
communication between hosts or devices
103GPP, IEEE
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• Now around 1B hosts!• But count only hosts with domain
names
Internet hosts
Network prefixes
12Source: bgp.potaroo.net
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Traffic breakdown• Cisco: By 2013 Video Will Be 90 Percent Of All Consumer IP Traffic
And 64 Percent of Mobile
Environment: trusted → untrusted
• Requires a far more secure Internet– What do we mean by security?– What aspects are the network’s
responsibility?
• Major design challenges:– Resilience to large-scale external attacks
(DDoS)– Resilience to compromised routers– Easy authentication of data– Forensics and auditing– Providing both accountability and privacy
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users: researchers → customers
• Customers demand high availability– Service is almost never interrupted
• Internet was designed for strong recovery properties– Recovering from serious failures
• How can the Internet provide 5 9’s of availability?– and doing so in a cost-effective manner– Internet currently at 2-3 9’s
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operators: nonprofit → commercial
• Operators must be able to manage their networks– Configuration– Troubleshooting– Middleboxes (proxies, firewalls, NATs, etc.)– Policy (routing, access control)
• What are the right abstractions for management?– What mechanisms best support them?
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usage: host-oriented → data-oriented
• Internet was designed around a host-oriented model– User tells client to contact another host (telnet,
ftp)• Current usage is mostly data-centric
– User wants to access particular data or service– Does not care where that service is located
• Mismatch currently handled by ad hoc mechanisms– Akamai, P2P
• Right abstractions for a data-oriented Internet?
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connectivity: e2e IP → intermittent
• Architecture assumes end-to-end IP connectivity
• In some niche settings, each link is intermittent and end-to-end connectivity is rare– Space, underwater, developing economies– Led to call for “delay-tolerant networking” (DTN)
• More generally want to shield applications from networking details– Opportunistic and context-dependent communication
• What’s the right API to enable this generality?
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New requirements• Mobility • Scalability (e.g. network prefixes)• Traffic Explosion (Especially wireless)• Multicasting/Broadcasting• Security• Delay tolerant networks (DTNs)
– E.g. vehicular ad hoc networks (VANETs) • Multimedia, realtime applications
– Video Adaptation– QoS, QoE
• Data center network• Cyber physical system (CPS)• E-911
– Should be able to disseminate emergency info– Spatial distribution
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