Monday, June 13, 2011

Ping time from Cuba to the US

Ping is a simple utility program that comes with every Mac or Windows computer. Ping records the time it takes to send a data packet across the Internet and to receive an acknowledgement of receipt from the remote computer. A colleague in Cuba recently ran a ping test from his computer, which was on a dial-up link, to Google in California. The results were:
Pinging [] with 32 bytes of data:
Reply from bytes=32 time=701ms
Reply from bytes=32 time=751ms
Reply from bytes=32 time=707ms
Reply from bytes=32 time=683ms
His computer sent four 32-byte packets to the Google computer with the Internet protocol address When the computer at Google received each packet, it sent back an acknowledgment, and the computer in Cuba recorded the time it took from sending the packet to receipt of the acknowledgement.

In this case, the first packet took 701 milliseconds, and the other three 751, 707, and 683 milliseconds respectively. The average of the four was 710 milliseconds.

Well, 710 milliseconds is only 7/10s of a second, which sounds pretty fast for a 5,100 mile round trip, but it is too slow to support many applications. For example, you would not be able to carry on a conversation using Skype. The length of the ping times and their variability (from 683 to 751 milliseconds) would make conversation impossible. Web surfing would also be very slow because modern Web pages do not come all at once -- they require many separate connections to get all the words, pictures, audio and video as well as behind-the-scenes links to computers that track your actions and insert ads.

The majority of the Ping time was due to the slow satellite connection between Cuba and the outside world. What about the time to reach another computer within Cuba? My Cuban colleague pinged a computer that was on the same ISP local area network as his:
Pinging [] with 32 bytes of data:
Reply from bytes=32 time=112ms
Reply from bytes=32 time=126ms
Reply from bytes=32 time=101ms
Reply from bytes=32 time=103ms
The average time has been reduced to 110 milliseconds, but the variability remains high. This speed would support a Skype call and, since Cuban Web pages are on the average much simpler than elsewhere, Web surfing within Cuba would be much less frustrating than international surfing. However, the dial-up link to the ISP, coupled with relatively slow equipment in the ISP network, leaves speeds far short of those in many nations.

For example, I pinged Google from my home in Los Angeles:
Pinging [] with 32 data bytes:
Reply from bytes=32 time=18ms
Reply from bytes=32 time=17ms
Reply from bytes=32 time=19ms
Reply from bytes=32 time=17ms
The average time is 17 milliseconds and there is only 2 millisecond difference between the slowest and fastest transmission. This connection is fast enough for viewing complex Web pages and phone chats.

The bottom line is that since the Internet in Cuba is slower than the US, Cuban applications are less varied and sophisticated. (Don't let that go to your head if you are in the US because other nations have still higher speeds, enabling them to develop and deploy more sophisticated applications than we do. For more along those lines see these posts).

Will the situation change when the undersea cable between Cuba and Venezuela is operational? If your ISP or organization network is not connected to the cable nothing will change. Whether or not you can connect, is both a political and an economic question.

If you are allowed to connect through the cable, expect about 600 milliseconds to be cut out of that Ping time to Google. That will be good news, but, if you are connected using the current dial-up, ISDN or slow DSL infrastructure, you will still be significantly worse off than I am in Los Angeles.

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