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Posts from April 2007

Skype provides more detail about the Call Transfer API

Last week Skype came out with a Developer Program newsletter that provided a bit more insight into the Call Transfer capability now available in the recently released Mac version 2.6. In the full version of the article, Skype technical project manager Morné van Dalen answers some questions about what the Call Transfer API is all about.  It's interesting to see the discussion here of Group transfer, specifically in this list:

  • Skype to Skype (P2P)
  • Skype to SkypeOut (P2P to SipOut)
  • SkypeIn to Skype (SipIn to P2P)
  • SkypeIn to SkypeOut (SipIn to SipOut)
  • Skype to Group
  • SkypeIn to Group

It's quite curious, though, that transfer to SkypeIn and SkypeOut will only be available to Skype Pro customers, which of course is not available in North America!  Seems a rather puzzling disconnect.

Anyway, it will continue to be interesting to watch these capabilities evolve...

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Mitel announces $723 million agreement to buy Inter-Tel

Yesterday after the close of the market, my employer, Mitel, announced an agreement to acquire Inter-Tel.   There's not much I can say beyond what's in the news release... but I can say that I am quite excited by the news!

Light blogging ahead for the remainder of the week...

It's a school vacation week here in my part of the USA and I'm planning to be offline for the remainder of the week.  Getting outside with my family... going on some day trips, doing some landscaping and otherwise enjoying the beautiful weather we are having right now.  I expect to be back posting here on Monday, April 30th.  See you then.

Blue Box Podcast #56 posted, beginning a series of VoIP security tutorials

I posted Blue Box Podcast #56 tonight and with it Jonathan and I are beginning a series of mini-tutorials on subjects related to VoIP security.  In this show, we talked about voice encryption. In the next show (already recorded) we will talk about signaling encryption.  The idea is to cover some basic ground so that people not familiar with the area can have a basic understanding.

Just glad to get that one up - tomorrow I'm going to work on #57 to see if I can get it online for Wednesday.  We're trying hard to get back on a weekly schedule.  (#56 was intended to go up last week.)

Microsoft: When simply having an IM conversation becomes a tool to raise money for nonprofits... is this for real?

We've all undoubtedly seen the chain-letter email messages that circulate around telling you that by forwarding the email you will make money or receive gifts and most people with half a clue understand that this kind of thing is pretty much impossible.  So it was with a whole lot of skepticism that I first greeted Microsoft's "i'm" campaign because the premise is: for every IM conversation you have with Windows Live Messenger, we'll donate some money to the nonprofit of your choice (from among nine choices).  To me, it sounded just a wee bit fishy.   In reading the "About" page you do learn a bit more.  First:

Every time you start a conversation using i’m, Microsoft shares a portion of the program's advertising revenue with some of the world's most effective organizations dedicated to social causes. We've set no cap on the amount we'll donate to each organization. The sky's the limit. There's no charge, so join now and put our money where your mouth is.

and then this:

Once you've signed up, every ad you see in your message window contributes to the grand total we send to the causes.

So it's all about a portion of the advertising revenue that is generated from use of Windows Live Messenger (formerly "MSN Messenger").  But this second piece I find interesting... it sounds like Microsoft must be being paid on a pay-per-view basis versus pay-per-click.  The advertisers pay MS based on the number of times that their ad is displayed.  Ergo... the more IM conversations there are, the more times the ads are displayed... the more money goes to Microsoft.... and the more can be distributed to the nonprofits.  I was a bit surprised as I would have expected it to be more like pay-per-click - and undoubtedly it still is, i.e. for a view an advertiser pays $X and if someone clicks through an advertiser pays $X + $Y.

Digging into the Press area, there was the FAQ that explained a bit more:

Q: How much money goes to the organization from each conversation?
A: Although the donation amount from each user is small, the power of the Windows Live Messenger network makes this donation significant. For competitive reasons, we can’t share the per-conversation amount of advertising revenue that we will contribute, but every new conversation you have will lead to money being donated to the cause you select. Each organization is guaranteed a minimum of $100,000 for its involvement.

So ultimately it will amount to at least $900,000 in money being given out to these nonprofit organizations... certainly nothing to dismiss!  There was also this little piece of curiousity:

Q: Can everyone participate in this initiative?
A: The i’m Initiative is available to everyone in the 50 United States and the District of

Huh?  I first learned of it from a friend in the UK who signed up for the initiative.  How would Microsoft even know, anyway?  Last I knew you didn't really have to divulge geographic details to sign up for WLM... and even if you did those could be bogus... and people move all over the world anyway.  Strikes me as quite odd.

Regardless, kudos to Microsoft for finding a fun way to make donations to some worthy organizations.  I'm not so naive as to think Microsoft is doing this entirely out of the goodness of their hearts - I do realize that they hope to: a) attract more users to WLM; and b) increase the number of views of their advertisers ads.  I assume they hope that it will incent people who use multiple IM services to have more conversations on WLM because those conversations will count for $$$. Probably not a bad idea.  For me, WLM happens to be one of the two primary consumer IM services I use (the other being Skype) and for whatever reason the sets of people I communicate with are pretty separate.  So it won't really change my behavior, but I could see that potential where people have more overlap between their contact/buddy lists.

To go back to the beginning, why is this "real" when the email scams aren't?  Remember that the major consumer IM services (WLM, Yahoo!Messenger, AIM, Skype) are all "walled gardens" and in the server-based services (WLM, AIM, Yahoo) the companies controlling the servers know precisely how many conversations are going on, who is having them (and in fact what is being said).  In contrast, with email the network of servers is completely distributed with no one controlling them all.  As long as the walls remain, the companies controlling the servers have all that data.  (Skype is a wee bit different, being peer-to-peer.)

In any event, it's an interesting initiative and it's great to see companies trying out new things that do benefit nonprofit organizations trying to bring about change in the world.  Kudos to Microsoft - and if you are a WLM user, check out the initiative... it's very simple... if you already have WLM 8.1, just add a text string to your display name.  If you don't have WLM 8.1, you'll need to upgrade. (Hmmm... which might be a third benefit for Microsoft - encourage people to move to the latest version.)


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Telephony disrupted: It's darn hard to be a remote teleworker without Net access!

About 1:30pm today, I lost internet connectivity.  It was quite comical, really, how I noticed.  For some reason, I did something I almost never do and hit the "Music On Hold" button on my teleworker sets hanging off of Mitel's switch up in Ottawa.  So there, in a wonderful use of bandwidth, radio station CHEZ-106 out of Ottawa was streaming into my home office down here in Vermont.  (That's what the trial guys are using as the MOH music source for the trial switch to which I am connected.) 

All of a sudden, the phone started playing the same audio packet again and again and again... I felt like I  was transported back about 25 years to the era of skipping records!  I wondered what was up but then I noticed a browser window on my computer not being able to find a link I had just opened to a popular web site.  I quickly looked at my other teleworker phones and they, too, were going into a resiliency mode attempting to failover to their secondary IP-PBX.  A glimpse at my laptop showed that Skype, MSN, Jabber were all starting their contortions of trying to reconnect.


Being a network geek, I did the usual response of ssh'ing into my home network gateway, looking at the routing table and trying to ping the next hop router.  Nothing.  Then I did the usual "consumer-hooked-to-a-cable-network" response of power-cycling the cable modem and then re-trying the ping.  Nothing.

A quick call to a neighbor who is also a home office worker got me this: "Oh, yeah, they've cut the Internet access as part of the re-wiring they are doing to the neighborhood power lines. Didn't you get the letter?  There are all sorts of Burlington Electric, Comcast and Verizon trucks up there right now. "


We did get "the letter", but given that this is school vacation week and we'd been planning to go away, I'd actually forgotten all about the potential problems.  Since we decided to stay around, the issue hadn't re-entered my consciousness...  perhaps we'll rethink those plans!

I kind of feel like I'm back teaching the "Intro to Networking" classes I used to teach where I'd always say, "Probably 90% of networking issues are Physical Layer - always check your cables first."   If the power company cuts your Net access... there's not really much you can do!

(2:20-ish - Net back up... (or else I'd be hard-pressed to post this note))

Asterisk running on a Roomba - "Press one to start sucking"

Here's something for a Friday afternoon... yes, indeed, out at Emerging Telephony 2007 back in February, someone (David Troy) did indeed have Asterisk running on a Roomba.  And yes, it was "Press one to start sucking. Press two to stop sucking."

Pictures are now available on Flickr.

More precisely, Asterisk is running on a hacked Linksys WRT54G access point (which is Linux-based) and the controller is using a Nokia WiFi/GSM phone to connect to the Asterisk install.  You could also control the direction of the Roomba using the other keys on the phone keypad.

Why would anyone do this?  Well... why not?

As I mentioned in a recent post, the beautiful thing about VoIP is that it now enables people to "play" with telephony... and do wacky things like hook it up to a Roomba!  :-)

Enjoy the weekend!  Perhaps next week I'll actually get some time to upload the rest of the pictures I took out at ETel. (Hey, it was only 6 weeks ago... )

IETF approves RFC standard for adding dialstrings to SIP

In the usual (and ongoing) flurry of IETF announcements, there was one notice that caught my attention.  It announces that an Internet Draft document about "dialstrings" has been approved to become a standards-track RFC.  So what, you say?  Well here's a bit more info:

This document provides a way of incorporating a dial string into the SIP or SIPS URI scheme. A dial string is a cousin of a telephone number, but rather than taking the form of a fully-qualified E.164 or national-specific telephone number, it is a description of a literal set of dialed digits that would be delivered over a POTS line. As such, it may include pauses, omit prefixes like area codes, and its applicability is necessarily restricted to a particular context (an enterprise, a LATA, etc). Support for dialstrings was formerly a feature of the tel: URI scheme specification (back in RFC2806); since that functionality did not make it into the revision (RFC3966), it is provided here specifically for the SIP and SIPS case.

Think of it as extra digits you have to type when making a call... or extra keys you have to press to start a service.  The challenge is that SIP proxies and other services need to know that it is a string of numbers that should be handled in a special manner, rather than just thought of as part of a SIP address or something like that.  I mention it here only because it's one of those really low-level things that you can do on the PSTN but until now haven't had a (standard) way to do in SIP. It's also one that ultimately anyone implementing SIP will need to implement.  No RFC number yet, but that will come soon.  Note the nice security warning:

Dialstrings exposed to the Internet may reveal information about internal network details or service invocations that could allow attackers to use the PSTN or the Internet to attack such internal systems. Dialstrings normally SHOULD NOT be sent beyond the domain of the UAC. If they are sent across the Internet, they SHOULD be protected against eavesdropping with TLS per the procedures in [RFC3261].

Yep... as we've been saying over at VOIPSA and Blue Box, you definitely need to think about encrypting SIP if you are sending it across the Internet.  If not, bad things will happen eventually.

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VoIP Now confirms that the cool kids hack telephony with their list of 74 open source VoIP / IP telephony projects

As I travel around giving presentations about the technologies that are disrupting telephony, one of the themes I discuss is that one of the most severe disruptions brought about by VoIP is that people now have the ability to "play" with telephony in ways that were never possible before.  Pre-VoIP, you needed special (and typically costly) equipment.  Yes, there have been any range of CTI cards that let you play to a degree, but buying the real equipment was just not possible for most folks who might want to "hack" in the original meaning of the word.  Enter VoIP.  Now all you need is an old PC and some open source software and... ta da... you're playing with telephony. 

What I also see out there is that this ability to hack on telephony is happening at the same time that hacking on networks or operating systems seems to be getting less exciting and interesting.  Oh, don't get me wrong, there's still amazing things happening out there... but for people who want to "play" with technology, those areas aren't as exciting or novel as they once were.  So many of those early adopters have moved on to hack on other things... primarily, it seems to me, on "Web 2.0" apps/services/mashups... or telephony.  (And you'll note the already happening collision of both.) 

Because I like giving presentations with very minimalist slides (unless forced to bulletize), I often summarize this latter point as:

The cool kids now hack telephony.

Whether you agree or disagree with my point, I don't think anyone can deny the continued growth in the number and capability of open source telephony projects.  By way of voiploser's blog (also worth checking out), I learned of VoIP Now's list of 74 Open Source VoIP Apps and Resources.  It's a great list, which really serves to illustrate the amount of open source activity happening with regard to telephony.   Some of the projects on there have been around for quite a long time, while there were certainly some there that were quite new (and I'd not heard of them).

My only quibbles with the article would be these:

  • There appears to be no way to leave comments, which is too bad, because you would undoubtedly get all sorts of other developers coming out of the woodwork and leaving comments saying "Hey, what about my project?"
  • No matter how you structure a list, people will always say it's wrong.  So naturally, I question why you would start with "H.323 Clients" given that all the major work these days is on SIP.
  • Given my past interaction with FreeSWITCH (read the comment left by the lead developer), I somehow doubt that they would want to only be classified under "H.323 Clients".  In fact, the inclusion there really makes absolutely no sense to me given that FreeSWITCH is decidedly not a client, but rather more a telephony platform.  It should probably have gone down near the PBXs or in a separate "platforms" category.  Ditto with YATE.  Part of me wonders if the author just wanted to list FreeSWITCH as #1...
  • Under "SIP Test Tools", they list some of the more prominent ones, but the VOIPSA "VoIP Security Tools" list has far more, most all of which are also open source and are used to "test" your VoIP system.

Quibbles aside, the list is definitely a good one, and kudos to VoIP Now for putting it together.

Issues with viewing this blog site with Microsoft IE6

If you are viewing this site in Microsoft Internet Explorer 6 (IE6)
there are problems with my new design that cause it not to render
correctly.  Until I can get time to fix it, your only choices are unfortunately to
either: 1) upgrade to IE7; 2) use Firefox; or 3) read the RSS feed.

My apologies... when I was testing the site design and navigation bar on top,
I tested the site with IE7, Firefox 1.5 and 2, and MacOSX Safari., but neglected
to test with IE6.

P.S. And if there are any CSS experts out there who know why my design
is messing up IE6, any such advice would be greatly appreciated.