Skills: use ping Concepts: network transit time, command-line user interface vs. graphical user interface, prefixes for small quantities

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Ping demonstration

Where does this topic fit?

• Internet concepts– Applications– Technology (communication)– Implications

• Internet skills– Application development– Content creation– User skills

Client Server

1101101

Acknowledge

Ping

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=53Reply from 74.125.224.84: bytes=32 time=17ms TTL=53Reply from 74.125.224.84: bytes=32 time=19ms TTL=53Reply 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?

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=110Reply from 146.155.99.60: bytes=32 time=180ms TTL=110Reply from 146.155.99.60: bytes=32 time=177ms TTL=110Reply 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?

Mind blowing speed

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

Try ping yourself

Start > Command

A command-line window

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?

Request timed out

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

Speedtest.net

Blip – better than Ping or Speedtest.net

Blip DocumentationRun BlipRun Blip full screen

Prefixes for small quantities

Prefix Meaning FractionDeci One tenth 1/10Centi One hundredth 1/100Milli One thousandth 1/1,000Micro One millionth 1/1,000,000Nano One billionth 1/1,000,000,000Pico One trillionth 1/1,000,000,000,000

Summary

Client Server

1101101

Acknowledge

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?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.

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/

For more detailed information on performance:Network Diagnotic Tool (NDT)