Skype Journal: Pesky facts
October 6, 2005 08:29 AMReality is hard enough to make out without distortion. So facts, data from facts, and testable logic make me happy. Ecademy's Julian Bond fact-checks and rebuts Kevin Tolly's Computerworld opinion column. Tolly called Skype "hazardous" to network health, a poor corporate citizen, and a bandwidth stealing freeloader. Bond says the article is "full of half truths and downright lies."
Your corporate desktops and notebooks are the peers that are consigned as Skype pleases to relay traffic and function as mini-servers in the Skype universe.
If your PC is directly connected to the net with no intervening firewall then there is a possibility of it becoming a supernode. That eliminates every corporate PC. Have you ever seen a corporate network with no firewall?
According to Skype — and validated by our research — a VoIP call will consume between 24 and 128kbit/s. When a Skype station is functioning as a relay the bandwidth is doubled.
If your PC becomes a supernode, you will relay switching traffic and not voice traffic to an expected maximum of 5kbps, according to Skype staff on the Skype forums. Go ahead and do the tests to prove them wrong.
One of the very cool things Skype has done is to publish a few near-real-time statistics to their web site. The statistics rss feed includes "Total Skype Downloads" (177,001,209), "Users Online Now" (3,780,794), and "Total Minutes Served" (14,310,738,687). By looking at the changes in these numbers you can understand more about the size, state, and trends of the skypopsphere's collective behavior.
Reull Consulting, a German consulting firm, sells 
weekly charts of this data. Here's a thumbnail from their Skype VoIP Statistics Week 39 2005 report, (US$199). It shows Minutes Served (top line) and Users Online (bottom line) from 26 September through 3 October, at 30 minute intervals. Minutes served in a half-hour peaked near 2 million, users online near 4 million.
Skypeteer 
offers a free flash widget. It shows the number of Skype users online. You can add it to your blog.
Skype Journal has its own number story. In the last seven months we've grown to 71 thousand unique visitors per month, each of whom come about every 8 days, reading 3.3 pages each visit. These are our conservative numbers, after removing search engine and spam activity. 
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Comments (4)
Interesting that "Reull" sells it. 200 US$ is not that cheap :-(. I gave similar graphs for free some months ago to the Skype Journal and to Mathaba. :-)
Posted by: Jean Mercier at October 6, 2005 2:46 PM
Please help me to clarify two points. When the potential starvation of Supernodes is raised, we are told that even clients behind NAT/FW can act as supernode. According to Bond, that is not the case. So which one is correct?
Also aside from Supernodes, doesn't Skype uses media relay nodes that (depending on the NATs involved) need to be part of the call for the full duration?
Thanks
Posted by: Aswath at October 6, 2005 5:30 PM
it would be interesting to have this for companies with a specific set of users online. i am not in the least interested in the 3 mio users.
Posted by: tropicaljantie at October 10, 2005 3:30 AM
This has the details Aswath is looking for:
http://www1.cs.columbia.edu/~salman/skype/index.html
Clients behind FW/NAT cannot act as supernodes - at some point everyone will realize this and then there will be no more supernodes. Skype does use intermediate relay nodes for call routing.
Posted by: Casual Reader at November 3, 2005 9:10 AM