SIP in higher education

[Ben Teitelbaum <>]

I'm unclear on how much traffic a typical Skype supernode actually
generates.  The numbers I've been able to find are all over the map.
For example, [1] finds the median bandwidth utilization per supernode
to be only 205 bps (not Kbps), while [2] claims:

  "Over the period of 20 days, we observed a total of 341
   Skype-relayed bursts of packets, corresponding to a total of
   1.11Gbytes of data.'

which is an average of about 5 Kbps (or 25x what [1] found).  A study
from JANET [3] includes a plot that shows sustained traffic in excess
of 30 Kbps (6x what [2] found and 150x what [1] found!).

Does anyone have any measurements or rules-of-thumb for average or
peak loads generated by a Skype supernode?

Cheers,

-- ben

1. An Experimental Study of the Skype Peer-to-Peer VoIP System,
   S. Guha, N. Daswani, R. Jain, IPTPS 2006. 
   http://iptps06.cs.ucsb.edu/
   http://saikat.guha.cc.nyud.net:8090/pub/iptps06-skype/

2. "Characterizing and detecting relayed traffic: A case study using
   Skype", Kyoungwon Suh, Daniel R. Figueiredo, Jim Kurose, Don
   Towsley. 
   ftp://gaia.cs.umass.edu/pub/Suh05_relay.pdf

3. "Skype and JANET",
   http://www.ja.net/development/voip/skype&janet.pdf

-- 
Ben Teitelbaum   http://people.internet2.edu/~ben/