VUC500: A Special Event Featuring Dr. Henning Schulzrinne

Friday, August 1st will see Dr. Henning Schulzrinne appearing as our featured guest for the 500th(!) edition of the VoIP Users Conference. While presently the CTO of the FCC, Dr. Schulzrinne has along history as a pioneer in the field of real-time communications over IP networks. He is responsible for the creation of such protocols as RTP and RTSP, and co-creator of SIP. He is a co-chair of the Internet Technical Committee of the IEEE Communications Society. His name appears on numerous RFCs.

In 2013 Dr. Schulzrinne was inducted into the Internet Hall Of Fame. The following clip is his acceptance speech from that ceremony. I offer it in the hope that it will help inspire some good questions.

The technical part of this weeks exercise will involve the use of Jitsi Video Bridge ( to host the call instead of our usual G+ Hangout. Thus we’ll be taking a pure, open source, WebRTC approach to things. Given a limited number of seats on the Jitsi video bridge they are by invitation only.

To allow more people to watch the call the Jitsi Video Bridge feed will be live streamed to our YouTube channel*.

Jitsi Video Bridge has a newly implemented ability to dial out to a SIP URI. This is how we’ll be interconnecting with ZipDX. Since both JVB and ZipDX support  the Opus codec that will be a good quality connection.

Interactive, if audio-only, participation in the call will be possible by connecting to ZipDX via SIP URI (

The audio will also be streamed live via Mixlr.

A big thank you goes out to Emil Ivov and the Jitsi team for setting this up!

*The mechanics of exactly how we’re feeding YouTube from JVB I will likely describe in a future post.

Recent Thoughts About The Edge of My Network

monowall-pfsense-alix-kitIn recent weeks I’ve been accumulating some thoughts about the edge of networks, and the edge of my home office network in particular.

This all started last month where there was an Ars Technica article describing how someone found a backdoor that allowed an evil-doer to gain admin access to a common consumer combination DSL Modem/router/Wifi AP. The author initially proved the exploit by hacking his Linksys WAG200G wireless gateway.

The article describes how he published the script used to run the exploit. That allowed others to try the exploit against various makes/models of consumer hardware. It thus came to light that the same trick works against various products from Linksys and Netgear, amongst others.

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Ekiga v4.0 Released

Ekiga-LogoThis week saw an announcement about the release of Ekiga v4.0. This is the most significant release of the venerable open source soft phone in some time. It brings with it many improvements.

I’m especially interested in the following new capabilities:

  • New audio codecs: SILK (used by skype), G.722.1 (aka Siren 7), G.722.2 (aka GSM-AMR Wide band)
  • Video codecs changes: H.264 optimizations
  • Added RTP TOS support
  • Support for DNS SRV caching

While developed primarily on Linux Ekiga has long supported multiple platforms. I took a short while today to try the new release on an older Windows XP laptop. The Windows installer also installed the GTK libraries necessary to support the application. Installation was quick and painless.

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PBXact: Unexpected Magic

If you were keeping an eye on the realm of open source PBX offerings you might be lulled into thinking that there is Digium with Asterisk and Switchvox, then everyone else. Where “everyone else” was basically hobbyists and Freeswitch fanatics. Well, that’s easy to understand, but you’d be wrong. I know that I was.

TMC recently posted an interview with Tony Lewis of Schmooze Communications. I know, I know…how do you take a company with a name like that seriously? It’s just one step above Goober Networks..oh,wait…they’re a real player, too! Well, what’s in a name?

Until today Schmooze Communications didn’t mean anything to me. However, I was enlightened by Michael White from E4 Technologies who is distributing  Schmooze Communications‘ product….PBXact.

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Royalty-Free Is The New Fashion In Codecs

It’s only mid-week and it’s already been quite a trip in the audio codec landscape. Broadcom announced that they are releasing into open source under the LGPL their BV16 and BV32 audio codecs. The relevant page on their web site includes documents outlining the techniques implemented in the codecs and C source code.

I’m not familiar with either of the Broadcom codecs. I see that they are available in some versions of Counterpath’s X-Lite and Eyebeam soft phones. Support for these codecs in hardware is something that I’m yet to determine.

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Choosing A Router/Firewall For A Small Office

net4801_2_lOne project that I’m am about to start is moving from my m0n0wall router to a new one build around pfsense. The motivation for the project is the integration of our Comcast Business Class internet service into the rest of the household. At present there are two separate networks, with only a few devices enjoying the high speed cable service. The pfsense system will be configured for dual WAN, accessing both the cable service and Covad DSL circuit.

My existing m0n0wall runs on an old Soekris Net4801. In service for many years, it has been extremely reliable. If m0n0wall does what you need I have no hesitation in recommending the software. Support from the user community is tremendous as well.

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