And while we’re on the subject of VoIP… TrixBox now has a 2.0 version available. I downloaded and installed this on another machine, before realizing that, like Dorthy, all I had to do was click the heels of my ruby slippers together three times, and I could upgrade my current Trixbox to version 2.0. And indeed that is all it takes; running the upgrade script, letting it chug for an hour or so, and then going in on the FreePBX interface and running the module upgrade procedure for FreePBX.

2.0 includes new versions of almost everything, including a release candidate 1 of FreePBX 2.2.0. So, now I have TrixBox 2.0 with FreePBX 2.2.0 which manages Asterisk 1.2.13.

Over at the Digium they are touting the Asterisk appliance, which is intended as a Trixbox competitor. This comes with Asterisk 1.4.0, beta a notch more recent than the version provided with TrixBox. I flirted with this; installed it actually, but then ran into some problems. I was intrigued however, to see that there was some additonal support for H.323 video…does this means that Asterisk will someday compete as a videoconferencing multi-point control unit (MCU)?

While the new interfaces are fine, the great news from my perspective was that the update blew away my IAX2 trunk configurations for VoicePulse. It left, however the VoicePulse SIP trunks, and I’ve been using them for two days without difficulty, not a single reboot or missed call. Call quality seems to be consistantly good. If this continues, I may actually get confident enough to apply for a phone number for the VoicePulse trunks and use them for inbound calls as well as outbound.

I’ve been using VoicePulse for calls now for a little over a month. Calls within the U.S. have a rate of up to two cents per minute. Calls to Germany were charged 2.7 cents per minute. The one outlier was a charge of 75 cents per minute to directory assistance in the U.S. What a rip!

Wireshark is the new name for Ethereal. It is a GUI packet sniffing program which watches your network traffic and reports on what’s going on at the network level. Ethereal has been around for years, but it is an ongoing project that just seems to be getting better all the time. Among other things, it will discriminate and display packets that are typical VoIP packets, that is SIP (Session Initiation Protocol), and IAX2 (InterAsterisk Exchange).

Set up a Wireshark capture and you are bound to find a ton of stuff that may be irrelevant. You’ll see requests for web pages, OutLook going out and checking for new mail, DNS requests (where is mxdesign.net?) and ARP broadcasts (who is 192.168.0.9?). So, one of the first things to consider is filtering the captured packets as they are being examined. This is done by using a capture “language” to create filters that are compatible with a predecessor program called tcpdump. Mike Horn has written a tutorial on these, which includes a basic set of capture filters.

I was puzzled why I couldn’t see traffic from my Asterisk/Trixbox computer on my desktop workstation. It turns out they were connected with a network switch which isolates traffic from individual devices. This makes network sniffing more difficult than in the old days when most LAN segments were connected via hubs. I ended up rummaging in the garage and found an older NetGear 16 port hub which I used to connect both stations, and Voila now I could see everything, the SIP phone calling the Trixbox, and the Trixbox calling out on the internet to Voicepulse. The Voicepulse tech support people want to see a capture file of just IAX2 packets, which should show (or not show) why my Trixbox occasionally loses the registration to the Voicepulse server. We’ll see.

A couple of interesting quirks have come up after about ten days of using Asterisk/Trixbox as our “home office” phone system.

1. The Grandstream Budgetone 101 and 102 SIP phones that we are using are not (apparently) FCC Type-B accepted. That means that they are not shielded to prevent television or other interference. So the phones make a hash of Channels 5 and 33 on our non-cable television….thereby rendering these phones essentially useless in a home environment. To be fair, they are a couple years old….maybe the new Grandstream phones are better shielded? So, the way we’re coping is to plug in the phone when we want to make a call. Saves power, that way, of course.

2. As described earlier, I’m using VoicePulse as our outbound call service, and it seems to work very well indeed. However, the IAX2 channels sometimes become unregistered with VP during the course of a day. When this happens, if you place a call via the VoicePulse trunk…you get a ring-no-answer…that sounds just like a conventional ring-no-answer..i.e. you can’t distinguish whether this is a problem with the VoicePulse registration, or if in fact the person really isn’t at home. As a precaution, in the morning, I’ve been making check calls to my cell phone….if the cell phone rings, then I know my outbound trunk is working. At the Asterisk command line, if I type IAX2 show channels, it should show two registered VoicePulse channels. Even if channel voicepulse1 is unregistered, I would have hoped that channel 2 would take the call, but there doesn’t appear any to be any logic that can deal with this issue. What I’d really like to see is some kind of real-time indication that the channels are not working, and/or some kind of fall-back or re-registering function.

3. I’ll be checking the power consumption of all the components, but I was pleased to see that the idle power consumption of the Dell server that I’m using goes at about 44 watts. This seems pretty reasonable for a server.