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Some pictures for class 1. cs480 spring 2016, NYU CS, Michael Walfish. The Internet is host-oriented and layered. home laptop. Web server. Much of the “intelligence” is implemented on the end-points. The middle of the network is “dumb” (in principle).
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Some pictures for class 1 cs480 spring 2016, NYU CS, Michael Walfish
The Internet is host-oriented and layered home laptop Web server Much of the “intelligence” is implemented on the end-points. The middle of the network is “dumb” (in principle). The architecture is layered; each layer plays a different role.
Case study: Web browsing DNS home laptop Web server http://www.twitter.com www.nytimes.com? <a href= http://www.nytimes.com/politics/article.html> cool story </a> 128.34.56.17 128.34.56.17 dst: 128.34.56.17 “GET /politics/article.html” The browser first turns www.nytimes.com into a network location Next, the browser forms an HTTP request
Case study: Web browsing DNS home laptop Web server TCP (transmission control protocol), UDP, … 128.34.56.17 dst: 128.34.56.17 1 “GET /po…” TCP is a transport protocol. It sequences data, decides when to send, and retransmits lost data
Case study: Web browsing DNS home laptop Web server IP (Internet Protocol) 128.34.56.17 dst: 128.34.56.17 src: 2.5.1.12 src, dst 1 “GET /po…” IP is a network-layer protocol. Its main job is to get packets delivered to their destinations
Case study: Web browsing DNS home laptop Web server Ethernet, 802.11, Infiniband, … 128.34.56.17 dst: 128.34.56.17 src: 2.5.1.12 src, dst 1 “GET /po…” Ethernet is a link-layer protocol. Its main job is to move packets around local networks
Case study: Web browsing DNS home laptop Web server 128.34.56.17 1 src, dst “GET /po…”
Case study: Web browsing Web server 128.34.56.17 home laptop Web serving software 2.5.1.12 src, dst 1 “GET /po…” “GET /politics/article.html”
Case study: Web browsing Web server 128.34.56.17 home laptop Web serving software 2.5.1.12 “OK 200 <article text>”
Case study: Web browsing Web server 128.34.56.17 home laptop 2.5.1.12 “OK <article>”
Case study: Web browsing Web server 128.34.56.17 home laptop <article> 2.5.1.12