EarthLink believes an open Internet is a good Internet. An open Internet means users have full end-to-end connectivity to say to each other whatever it is they say, be that voice, video, or other data exchanges, without the help of mediating servers in the middle whenever possible. We believe that if peer-to-peer flourishes, the Internet flourishes. SIPshare helps spread the word that SIP is more than a powerful voice over IP enabler — much more. SIP is a protocol that enables peer-to-peer in a standards-based way.

The emerging ubiquity of SIP as a general session-initiation enabler provides a rare opportunity to offer users all manner of P2P applications over a common protocol, instead of inventing a new protocol for each new P2P application that comes along.

EarthLink wants to point the way and aid the cause of these new applications by demonstrating in open source working code that SIP can host powerful applications beyond those that immediately come to mind, that is, voice and video.

We chose file sharing to illustrate how SIP can be used to build an alternate P2P application, but file sharing itself is not the point — file sharing, of course, has been done. EarthLink SIPshare demonstrates that it is conceivable that voice over IP, where voice is just content of a different form, itself can be implemented using SIP in a fully standards-based P2P network. In other words, the effect of Skype, but with one important difference: using standards-based protocols, as EarthLink SIPshare does for content sharing.