Google Talk supports SIP, what does Skype do now?

Now that Google has announced plans to support SIP in Google Talk and plans to "federate" with third-party providers including Sipphone's Gizmo Project and Earthlink's Vling, where does this leave Skype? Skype up to now has been able to deflect criticisms for using a proprietary protocol and not supporting SIP. Part of their "excuse" for using a proprietary protocol was that it was needed in order for NAT traversal of firewalls.

But how long can Skype use this "excuse" now that Google plans to adopt the SIP protocol, an industry standard and currently Google Talk also can do NAT traversal? I should point out that currently Google Talk's VoIP feature doesn't use SIP but instead uses a custom XMPP-based signaling protocol for its peer-to-peer communication mechanism. But no doubt Google will figure out how to use SIP and perform NAT traversal.

It is also worth mentioning that Google's embracing of the SIP protocol will put pressure on Skype to support SIP and this may have to change the business model of Skype. For example, there was talk of Skype charging a licensing fee per device fee to add Skype proprietary functionality to a cell phone for example. This completely goes away with SIP. You just gotta love standards!

Sorry Skype, I do love ya, and will continue to use ya, but the computing world and now the telecom world have become about open standards. Just look at Asterisk's success, an open-source IP-PBX, if you need further proof.

Google Connection May Pay Off for Asterisk

Online VoIP services are starting to turn up in all sorts of new places. Skype Technologies S.A. clients have been incorporated into the Salesforce.com Inc. application suite to provide communication.

Digium Inc., the parent company of the open-source IP PBX, Asterisk, has linked the client software of Google Inc.’s Google Talk to its Asterisk servers. Now, calls made to an Asterisk server can be forwarded to one or multiple Google Talk clients.

The ability to link VoIP servers, particularly business VoIP servers, such as Asterisk, to computer-based VoIP clients, such as Google or Yahoo! Inc., opens the potential for new communication services that combine PBX functions with online communication services.

Kevin Fleming, senior software engineer at Digium, said the link between Digium’s Asterisk servers and Google Talk required no formal agreement between the two companies. Asterisk can support Jingle, which has been described as an open version of the protocols used in Google Talk. Jingle is a set of extensions to Jabber, a suite of XML protocols widely used for instant messaging and presence. Google is supporting the development of Jingle through the Jabber Software Foundation's community standards process.

Asterisk can support Jingle the same way it supports other protocols, such as SIP, H.323, MGCP and Cisco Systems Inc.’s SCCP, better known as Skinny, by developing a kind of software signaling gateway, called a channel driver, to translate between Asterisk’s internal signaling and various VoIP clients, such as SIP phones. In fact there are few client devices, such as phones, that actually use the Asterisk protocol, IAX, so the Asterisk software has to be able to accommodate other protocols.

Flexibility was important on both sides of the connection between Asterisk and Google Talk. “The lack of any agreement between us and [Google] is proof that you can bring out a new service with a publicly defined protocol [Jingle] that any one can develop to – unlike Skype, which is closely guarded, encrypted and obscured,” said Fleming, “which is why nothing connects to the Skype network yet.”

Beyond its ability to work with other servers, Google Talk “came up with some very creative ways to do things, like NAT traversal and path determination and codec choosing,” said Fleming.

Open protocols, such as SIP or Jingle, give a software developer the ability to create applications that can work on SIP or Jingle networks.

A side benefit of the link to Google Talk and Jingle is that Asterisk might be able to federate with Google Jabber servers and even make use of Google Talk’s network for calling, such as for calls between companies with Asterisk servers, using standard clients, such as SIP phones.

Though Jingle and its parent technology, Jabber, are sometimes viewed as competitors to dominant VoIP protocol SIP, Jingle itself has something of an Internet Engineering Task Force (IETF) imprimatur. It is based on XMPP (Extensible Messaging and Presence Protocol, an IETF protocol for peer-to-peer multimedia. Google is supporting the development of Jingle through the Jabber Software Foundation's community standards process.

An official version of the Google Talk link will be in the next open-source release of Asterisk by Digium, which will be available in a beta version this week. Typically there is a one- or two-month period of bug testing, then a commercial release likely this summer.

Asterisk www.asterisk.org
Digium Inc. www.digium.com
Internet Engineering Task Force www.ietf.org
Jabber Inc. www.jabber.org