1. Skills: use ping Concepts: network transit time, command-line user interface vs. graphical user interface, prefixes for small quantities This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. Ping demonstration

2. Where does this topic fit? Internet concepts – Applications – Technology (communication) – Implications Internet skills – Application development – Content creation – User skills

3. Client Server 1101101 Acknowledge Ping

4. C:\Users\Larry>ping www.google.com Pinging www.l.google.com [74.125.224.84] with 32 data bytes: Reply from 74.125.224.84: bytes=32 time=18ms TTL=53 Reply from 74.125.224.84: bytes=32 time=17ms TTL=53 Reply from 74.125.224.84: bytes=32 time=19ms TTL=53 Reply from 74.125.224.84: bytes=32 time=17ms TTL=53 Ping statistics for 74.125.224.84: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 17ms, Maximum = 19ms, Average = 17ms C:\Users\Larry> Ping Google Why did some packets take longer than others?

5. C:\Users\Larry>ping www.puc.cl Pinging www.puc.cl [146.155.99.60] with 32 bytes of data: Reply from 146.155.99.60: bytes=32 time=182ms TTL=110 Reply from 146.155.99.60: bytes=32 time=180ms TTL=110 Reply from 146.155.99.60: bytes=32 time=177ms TTL=110 Reply from 146.155.99.60: bytes=32 time=185ms TTL=110 Ping statistics for 146.155.99.60: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 180ms, Maximum = 185ms, Average = 181ms C:\Users\Larry> Ping Catholic University, Santiago Chile Why are these times longer than in the previous example?

6. Mind blowing speed RT to Chile at around 62,000 miles per second – about 1/3 the speed of light.

7. Try ping yourself Start > Run

8. A command-line window

9. The result How many speed-test packets were sent? What was the longest round trip time? The shortest? The average? What is the 74.125.224.51 in this example?

10. Request timed out

11. A windows Ping client Which do you prefer – the Ping client with the graphical user interface or the one with the command-line user interface? Why

13. Speedtest.net

14. Blip – better than Ping or Speedtest.net https://github.com/apenwarr/blip#readme http://apenwarr.ca/log/?m=201304#26

15. Prefixes for small quantities PrefixMeaningFraction DeciOne tenth1/10 CentiOne hundredth1/100 MilliOne thousandth1/1,000 MicroOne millionth1/1,000,000 NanoOne billionth1/1,000,000,000 PicoOne trillionth1/1,000,000,000,000

16. Summary Client Server 1101101 Acknowledge

17. Self-study questions 1.Which organization owns the host with the IP address 74.125.0.0 ? 2.Ping www.microsoft.com from two places, perhaps school and your home. Are the ping times the same? Explain the differences?www.microsoft.com 3.If you measure ping time between two hosts at different times, will it always be the same? Explain your answer. 4.Data travels very fast across the Internet, but the rate is less than the speed of light. What things slow it down? 5.I pinged Google.com from my home and from my office. The results showed two different destination IP addresses. Can you explain that? 6.Which do you like better, the command-line ping program that comes with Windows or the window-based program that I wrote? Why? Give at least one advantage for each.

18. Resources To run ping from remote locations around the world, go to: http://www.traceroute.org/ For more on command line versus graphical user interfaces see: http://som.csudh.edu/fac/lpress//471/hout/misc/guivcli.htm To test ping times and data transfer rates (upload and download): http://www.speedtest.net/