From: Gareth Shearman Subject: IP telephony (update) Date: September 2004 In early February I posted a note entitled "new experiments in communication". I would like to update that now, particularly in reference to the section on VOIP or IP telephony. We are proceeding with our experiments here in British Columbia and continue to be very impressed with the capability of this technology. Here are some of the developments to date: We have replaced our office telephone system with a Linux computer system running the open source "Asterisk" software (www.asterisk.org) Our office telephones themselves have been replaced with SNOM 200 multi line phones. These digital phones connect to our LAN rather than to standard telephone ports. We have placed cards (Wildcard X100P) from Digium (www.digium.com) in the Linux computer which allows us to connect our incoming regular office telephone lines to the system. As part of our community network and not for profit ISP activities we maintain a number of Internet public access sites in various locations on southern Vancouver Island. Some of these sites are in communities outside of the Greater Victoria free dialing area. We are in the process of equipping many of these sites with Grandstream BudgeTone 100 single line VOIP phones. Thus the site patrons will be able to make free calls into the Victoria telephone system by linking through our office lines. We are also reselling these same phones to other individuals and organizations in British Columbia that wish them. We are configuring the phones to work with our Asterisk system. We want to promote the spread of IP telephony among our colleagues. We are encouraging other communities to develop their own Asterisk based systems. The systems can then be cross connected or "peered" with one another so that calls can be passed among communities. We are currently "peered" with two other British Columbia communities, using the IAX (Inter Asterisk Exchange) protocol. An Asterisk system isn't necessary for a community to be involved, their phones can be extensions of systems in other communities. A knowledgeable Linux "guru" is required to set up an Asterisk system. I would like to encourage the members of the GCNP group to consider joining us in this project. For people outside of British Columbia I suggest that you consider applying for a free Internet phone number from Free World Dialup in New York (fwd.pulver.com) These numbers can be used with the freely downloadable soft phones (PC, Mac and Linux versions available) or with hardware phones. The hardware phones are not strictly necessary but they do not require the installation of special software and possible hardware upgrades to your computer and they are easy to use and give good results. We are purchasing our Grandstream phones from Free World Dialup, but there are other distributors of these devices. Our system is configured so that we can connect to Free World Dialup numbers. The phones normally require high speed (DSL, Cable or better) access, although in some circumstances they can be made to work with 56K dial up lines. Results: Just how well do they work? Well, in most cases the phones, which come pre configured with your assigned "telephone number", just plug in to your local router and work straight out of the box. Pick up the hand set, "dial" the number and the phone at the other end rings. We have found that there are some exceptions to this, of course. If your local system isn't serving DHCP addresses you have to manually enter a static IP address on the phone's keypad. If there is a complicated institutional fire wall in the way, you may need help from your network administrator to open the appropriate ports. Then there are issues associated with the quality of your line. Not all Cable or DSL lines are created equal. A case in point has been the experiences that Ken Young in Australia and I have had communicating with one another. As soon as Ken got his Grandstream phone he connected it to his DSL line and called me. Result - my voice came through to him very well, but I had to strain to make out what he was saying through dropouts and an annoying lag. DSL lines are typically not synchronous, there is more bandwidth down than up and apparently his line wasn't quite up to the task. Ken suspects that in the residential DSL market the contention rates of consumers Vs bandwidth may be the problem. We have overcome most of this by changing the audio codec that he is using but it has taken some time and technical assistance to make it work. When he calls me from a different location (with a higher Quality of Service) the problems disappear and the resulting conversation is trouble free, which is a good indication that the quality of the line is very critical. These telephone services come with voice mail and the Asterisk server provides a teleconferencing capability. We have also found that the more forgiving "ilbc" audio codec that we have been using in our experiments with Australia has also vastly improved a local problem area where a phone is two wireless hops away. We have also shown this same codec makes it possible to communicate over dial up lines. We are still in the early stages of testing this but it does work There is, however, a pronounced lag while you wait for the other persons reply, unlike the higher speed connections which are at least as good as standard telephone calls. The ilbc codec is not the default codec used and is not always an option. Some of you have mentioned the service called "Skype" developed by the group behind the "Kazaa" file sharing software. It has only very recently become available for the Macintosh computers that we use. We are testing it and it seems to work well. It is, however, proprietary software and does not use the standard "Session Initiation Protocol" (SIP) that the other systems use. Although this may change it so far only exists as computer software. There is no opportunity for community networks to establish their own community services with Skype. Other Developments: In February I also mentioned the "iChat" software. At that time this software only worked on Apple Macintosh computers. It will now also work on Windows XP systems running the latest version of AOL's "AIM" software. Although this gives good results and also uses the SIP protocol it is a proprietary version. At present there is no capability for multiple sessions, it is one on one only. This is due to change early next year but it is rumoured that some aspects will be a commercial service.