Transcript 1) Internet-intro

i-1 Internet Intro
Taekyoung Kwon
[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
broken
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Another motivation
• Naïve researchers
ARPA -> Defense Advanced Research Projects Agency (DARPA)
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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
• Enable sharing of supercomputer power
• 4 nodes
– UCLA
– Stanford (SRI)
– UC Santa Barbara
– U of Utah
• Including BBN, some say 5 nodes
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Zoom in to UCLA
Interface Message Processor
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1972: Robert Kahn
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2000s: middle-age
• Now it faces problems
Applications
Applications
TCP UDP
TCP UDP
IP
NAT diffserv IPSEC
mobile IP mcast
intserv
Eth token
PPP 802.11
radio, copper, fiber
IP “hourglass”
Eth token
PPP 802.11
radio, copper, fiber
Expanding waist?
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Internet standardization
• Protocol: a set of rules governing
communication between hosts or devices
3GPP, IEEE
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Internet hosts
• Now around 1B hosts!
• But count only hosts with domain names
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Network prefixes
Source: 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
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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:
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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
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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 → dataoriented
• 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
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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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