1. W7D2

2. Internet (topology) (recap) Local Area Networks (Ethernet) packet switched networks LAN-s patched together Internet addresses (Internet Protocol address) Protocols

3. W7D2 Internet (US) up to 1995

4. W7D2 Tracking data 3 rd1lb-ge5-0-0-2.lb.shawcable.net (64.59.140.225) 4 rc1no-atm1-0-10.cg.shawcable.net (66.163.76.110) 5 rc1so-pos15-0.cg.shawcable.net (66.163.77.9) 6 rc1wh-pos12-0.vc.shawcable.net (66.163.76.10) 7 rc2wt-pos7-0.wa.shawcable.net (66.163.76.154) 8 74.125.48.233 (74.125.48.233) 9 216.239.46.50 (216.239.46.50) 10 209.85.250.144 (209.85.250.144) 11 216.239.48.143 (216.239.48.143) 12 209.85.251.145 (209.85.251.145) 13 74.125.31.174 (74.125.31.174) 14 po-in-f147.google.com (72.14.253.147) From my home --> www.google.ca

5. W7D2 Bill Cheswick, Bell Labs and Hal Burch, CMU

6. W7D2 Internet = possible because of Software:  software running on ISP’s computers & following protocols (ex TCP/IP)

7. W7D2 Internet Protocol analogy Jor-El Inter-galactic Post (protocol)Canada Post (protocol) “IP over CP”

8. W7D2 Internet IP = protocol giving:  Universal addressing scheme  Way to find routers Routers “translate” Internet packets to the “language” of the LAN.  Ex: IP over Ethernet

9. W7D2 Protocols Network protocols  TCP/IP Application protocols (fancier things)  Web pages HTTP  Transferring files FTP  Using computers remotely SSH  Streaming media (eg Internet radio) RTSP  Assigning names to addresses DNS  All run over TCP/IP

10. W7D2 Protocols & client server interaction Communication: P2P (client, server) EX: DNS  Names: gyrator.cs.uleth.ca (142.66.1.10)

11. W7D2 Example: DNS query applepie $ nslookup www.uleth.ca Server: 64.59.135.133 Address: 64.59.135.133#53 Non-authoritative answer: www.uleth.ca canonical name = www.netsrv.uleth.ca. Name: www.netsrv.uleth.ca Address: 142.66.6.116