190 likes | 285 Views
i-1 Internet Intro. Taekyoung Kwon tkkwon@snu.ac.kr. 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
E N D
i-1 Internet Intro TaekyoungKwon tkkwon@snu.ac.kr
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
Another motivation • Naïve researchers 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
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
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
Zoom in to UCLA Interface Message Processor
Applications TCP UDP IP Eth token PPP 802.11 radio, copper, fiber 2000s: middle-age • Now it faces problems Applications TCP UDP diffserv IPSEC NAT IP mcast mobile intserv Eth token PPP 802.11 radio, copper, fiber IP “hourglass” Expanding waist?
Internet standardization • Protocol: a set of rules governing communication between hosts or devices 3GPP, IEEE
Now around 1B hosts! But count only hosts with domain names Internet hosts
Network prefixes Source: bgp.potaroo.net
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
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
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?
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?
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?
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