Interview with Asterisk creator Mark of Spencer
Open SOURCE software conquers the Telefoniemarkt

The open SOURCE telecommunications software Asterisk is established ever more than favorable telephone system solution. The software does not only get along with “classical� telephone connections, but can also for Voice of over IP (VoIP) be used. A Business Case on heise open describes the structure of a VoIP gateway with Asterisk. Stefan Wintermeyer spoke with Mark Spencer, the creator of Asterisk and founders of Digium, the enterprise behind the free telephone IE software.
Mark of Spencer Mark of Spencer - the author of Asterisk and founders of Digium

SW: How old are you and when did you begin working with Linux?
Spencer: I am 29 years old. My first experiences with Linux were in 1994. I was 17 at that time.

SW: When, why and how have you the Asterisk project in the life called?
Spencer: Asterisk began as internal telephone system for our company, which was still called Linux support services at the time. We only changed our name to Digium in 2001 and moved Asterisk to the center of our activities.

SW: Is Digium a typical representative that new Economy?
Spencer: It is a small enterprise with a great atmosphere and a passionate team. It is not easy to change the world. I am proud to work with such enthusiastic people.

SW: How many people work for Digium and which for humans are those?
Spencer: The company employs around 60 staff for the moment. They work within fields such as sales, development and Testing.

SW: Why is the head office of Digium Huntsville in Alabama?
Spencer: One of our investors is Adtran, a large manufacturer of network hardware from Huntsville. In the time, when this financial injection came, we formed there. Huntsville is a small technology location in Alabama. I call it the Sillicotton Valley.

Sorry, I give up, someone else can take over editing from here! Some of this really doesn't make sense!

SW: Exactly the same as some other successful open SOURCE companies you placed your software under two different licenses. Why does Asterisk not exclusively stand under the GPL?
Spencer: For much standard software open SOURCE a good model is undoubted. I would like to offer however also the possibility to people of connecting Asterisk with prop. guessing eras applications. But to require, I find money quite attached, otherwise I could have taken also the GNU Lesser general Public License. The GPL forbidden besides linking to open SOURCE products, which stand under another free license, an example would be here OpenH323. Also with patented techniques such as G.729 such a software may not be linked. I would like to underline the importance of Wahlfreitheit again, but there must be also an economic incentive for open SOURCE.

SW: How should a developer proceed, that wrote an extension for the GPL version of Asterisk, but not its would like rights at Digium transfer?
Spencer: Here a misunderstanding is in the play. If someone liked to contribute code to Asterisk, he or she must grant us only the unrestricted use. Copyright at the software remains with the author. We do not undertake the copyright, although we think about it, to offer such a possibility if people wish. Who would not like to grant Digium the unrestricted right to use at its contribution, still its own derived work can place under the GPL. We cannot take up such changes however to the product, which we spread as Asterisk.

SW: What do you regard from the BRI extensions as Asterisk of Junghanns from Berlin? These stand completely and exclusive under the GPL.
Spencer: I consider BRI important. We cannot integrate the software however in Asterisk and at the same time maintain for example the support for G.729. Instead we use mISDN. Also we do not know exactly, from whom the BRI code comes, since it gives no code Tracking. That makes it difficult to examine the origin of the source texts.

SW: We turn now again to the normal Asterisk user: Everyone, which uses the stable version, saw itself in the last months at the latest all four to six weeks to an update forced. Many feel that as annoying. How does it come that there are still so many errors in the stable version of a so important software?
Spencer: Asterisk is a very complex product, which is used into amazing variety by environments. With exception some fewer errors, like the Denial OF service Sicherheitslücke against IAX, most nose rather the few users concern, must be repaired however nevertheless. Who attaches importance to a more conservative release cycle, for which a formalized test procedure is the basis, should fall back to Asterisk.

SW: What is the Asterisk Business edition exact? Wherein does the difference to the standard design lie?
Spencer: Is based completely on open SOURCE, with exception of the copy protection and some partner products, which are available. The main differences lie in the longer test and release cycle, the profesionellen support and the explicitly commercial license.

SW: What brings for Octobers the planned version 1.4 to the user? Is someone, which uses and thus well drives Asterisk 1,2 now, to transfer to 1.4?
Spencer: As we in Alabama say here: “So long it runs, omits the fingers.� Transferred is recommended, if there is a nose in 1.2, or if the new version offers functions, which there was not in 1.2 yet.

SW: How long do you want to offer nose-fixed for Asterisk to 1,2?
Spencer: So long, as the Maintainer of the 1.2-Releases wants to make these available.

SW: Why do you want to bring every six months out new stable release? Many people are the opinion that a telephone IE software should have a longer release cycle.
Spencer: There is an equilibrium between a shorter release cycle (the “releases early, the releases often�), which at open SOURCE software to be found frequent is, and a longer cycle, as it is to be found with most commercial applications. We believe that it is important to bring every six months out new release of the open SOURCE version of Asterisk. The Businesses edition is the platform for the longer release cycle with the formal test procedure. In this way we can correspond to the different needs of our target groups.

SW: Most Asterisk users use a SIP telephone. SIP is not necessarily safest minutes. How according to your opinion should a safe VoIP connection between two interlocutors be developed?
Spencer: Probably via IAX with a form of coding. Such a thing like the Denial OF service gap already mentioned may not naturally pass then no more.

SW: What do you hold from the coding software Zfone of Phil Carpenter?
Spencer: I did not use it yet.

SW: And of the Linux distribution Asterisk@Home?
Spencer: Asterisk@Home is the ideal test environment, in which people can become acquainted with Asterisk. It has naturally its restrictions, but it makes enters into Asterisk rather easily.

SW: How does the future of VoIP look in the coming two years?
Spencer: I think, Asterisk with VoIP a ever more important role will play. It is already remarkable that many of the correctly large enterprises look at themselves the software. Which concerns VoIP generally: Here will it, believes I, less and less over cost saving to go, but however many more around new services such as combinations out of language, video and data and around an improved quality in relation to the conventional telephone network.

SW: Will VoIP make the long-known telephone network for the normal user redundant in the near future?
Spencer: That depends on the location. Someone of Adtran said times “copper may be buried, but it is not dead� over the enormous quantity of copper lines in the soil. These leave themselves still marked out. Exactly the same there is still so much similar technology that it will still for a very long time last, before the whole telephone service runs off package-obtained. If already to America and Europe applies, then all the more for the remainder of the world.

SW: Why is SIP in such a way likes?
Spencer: SIP is like that something like a historical mistake. It was less complex than H.323 and open.

SW: Why aren't there any longer VoIP telephones, which support own Asterisk minutes IAX?
Spencer: For IAX there was until recently no documentation.

SW: What can you tell us about co-operation of Digium with Google?
Spencer: Asterisk ünterstützt Jingle, Googles extension of Jabber minutes, which brings a quantity of advantages with itself
Created by: sxpert, Last modification: Sun 17 of Sep, 2006 (19:47 UTC) by ZX81
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