An Analysis of the Skype Peer-to-Peer Internet Telephony Protocol Salman A. Baset and Henning Schulzrinne Department of Computer Science Columbia University, New York NY 10027 {salman,hgs}@cs.columbia.edu September 15, 2004 ABSTRACT Skype is a peer-to-peer VoIP client developed by KaZaa in 2003. Skype claims that it can work almost seamlessly across NATs and firewalls and has better voice quality