May 19, 2011, 2:09 PM — While many people use Skype for its free voice over IP (VoIP) services, Linux users have a love/hate relationship with it. Yes, Skype will run on some versions of Linux, but it doesn't run on all of them, and the Linux version (2.2-beta) lags far behind the Windows version (Skype 5.3). That's three major generations behind. Need I say more?
Much as I dislike Microsoft's recent purchase of Skype and even though I think Skype's technology is held together by bailing wire and duct tape, maybe Skype will become better for Linux with Microsoft. After all, it couldn't be much worse!
That said, there are numerous Linux VoIP programs and they're also free as in "free beer," as well as free as in "free software." Most of these programs use the open SIP (Session Initiation Protocol) standard or Extensible Messaging and Presence Protocol (XMPP) If they use the same protocol, you should be able to use one client to call another. To do this, of course, they must be on the same SIP or XMPP network. For example, I use the Ekiga.net VoIP network for SIP calls.
None of them, however, can work natively with Skype. Skype is a proprietary system and locks users into using it. You can set Skype up with Skype Connect to work with SIP VoIP systems, but this is a paid service. There are efforts afoot, such as the karaka Google Project to create Skype/XMPP gateways, but they're for developers, not ordinary users.
There are also numerous Linux based IM clients, such as Pidgin, that also include some VoIP support.
The Linux VoIP clients also have some other things in common. On the down side, none of them allow desktop sharing. That's not a feature I use very often, but it's one that's used all the time in technical support operations. In addition, except for the Google family of voice applications, none of them make calling from VoIP clients to phone company telephones easy.
So, that said, let's take a brief survey of Linux's Skype alternatives.
Linux-friendly VoIP clients
Ekiga: This program is perhaps the best known of the Linux VoIP clients. Formerly known as GnomeMeeting, it's an open source VoIP and video conferencing application for GNOME. Besides SIP, Ekiga also supports the H.323 videoconferencing protocol. With this protocol, Ekiga supports Microsoft NetMeeting interoperability. It does not, however, support Microsoft's newer Windows Meeting Space replacement for NetMeeting.
In my experience, Ekiga works quite well. In particular I was also pleasantly surprised at how well it worked with NetMeeting. If it weren't for the overall value in the Google Chat/Talk/Voice package, Ekiga would be my favorite Linux VoIP program. That said, if free software is a priority for you, then Ekiga is the program for you.
GNU Telephony is a project that has just reached the 1.0 stage. With the release of the GNU SIP Witch 1.0, a SIP server, this program is much closer to being something that end users would want to use. For now, though, GNU Telephony is better left for free software developers rather than users.
Google Chat / Google Talk / Google Voice. Sorry if I'm confusing you bu using three different names, but Google has made describing its VoIP service more than a little confusing. I'm reminded of the story of the blind men and the elephant. Depending on what part of the elephant you're touching, you'll have an entirely different perception of the whole beast.
