Volume 21, Number 7 - July 2005
|To Be Announced
To Be Announced
Thursday, July 21, 7:00 PM
The CACTUS Newsletter is a monthly publication, distributed to our members and other interested people. Visit the CACTUS Newsletter on the web at http://www.cactus.org/Newsletter/. There you will find archives of back issues, as well as instructions on how to subscribe to the e-mail distribution. We welcome newsletter submissions by our members. Please contact newsletter [at] cactus <dot> org for more information.
The program for July was not available at newsletter publication time. Be sure to join us at the meeting since even our ad-hoc topics are generally interesting and informative.
The next CACTUS meeting will be held on Thursday, July 21, 2005 at 7:00 PM (doors open at 6:30 PM for pizza and informal discussion), in the auditorium of UT Applied Research Laboratories. (See end of newsletter for directions to the facility).
Using his notes president Randy Zagar opened the meeting with a greeting to members and visitors explaining what CACTUS meant, our purpose, and our meeting schedule. He noted the elaborate drawing showing the hardware configuration used for the evening's demonstration of VoIP that Gil Kloepfer had put on the chalk board. Gil remarked that it wasn't more sophisticated than the previous demo, he just drew it on the board this time. Marc Scarborough announced that his employer was looking for someone for a short contract job. Gil mentioned that ARL:UT also had two positions open: one for a programmer in his department using Java and Python, and another for a system administrator in one of the research groups. Someone noted that M. H. Khan had forwarded a link from Kelly who was looking for a Unix system administrator for less than $10.50 per hour. Gil wanted to know if anybody applied for that position.
Before the presentation, Lenny Tropiano (one partner of VoIPing, LLC, one of CACTUS' sponsors) explained that he acquired some VoIP-related equipment when his previous employer, RockSteady Networks (formerly a CACTUS sponsor), fizzled out in December of 2004. Lenny ended up with a surplus of equipment at home, including a Cisco IP telephone (still worth about $200 on Ebay) and generic FXO (telephone line) interface card that would work with the Asterisk Open Source PBX. To help provide additional funding for pizza and programs, and to encourage others to get started with Asterisk, Lenny donated these two items to CACTUS for a raffle during the meeting (tickets were $5 each). He sold $105 worth of tickets to benefit the CACTUS treasury. Lenny explained that the drawing would take place at the end of the meeting.
Randy Zagar noted that one of the mirrored drives on Bubba was having spindle problems and won't reboot without human intervention. He explained that Tim Wood of Newisys had agreed to RMA the drive for CACTUS. Randy spoke for a minute about the June issue of Linux Journal, which had a story about cities deploying WiFi.
Treasurer Johnny Long was not present, but membership Luis Basto noted that he had checks for CACTUS. Luis complained that he was getting SPAM from people claiming to be Gil. This invoked a long discussion of qmail and SPAM filters. The membership agreed that a five second delay for an OK on the CACTUS mail server would be acceptable and useful in blocking certain mail attacks. They also liked the idea of responding with a "service not available" message the first time an unknown server connected.
Program chair John Christy mentioned that IBM has agreed to come back for another presentation. Someone asked Chris Boyd of Midas Networks if he ever got the right-of-way for his fiber connection. Chris retold the story adding a happy ending. This inspired Lindsay Haisley to ask, "Midas, I've heard good things about them. How do you like them?" Chris responded, "They're so good, that I founded the company."
Gil Kloepfer mentioned Luis Basto's newsletter contribution (that unfortunately didn't make the newsletter) about the telecom bill before the Texas Legislature. M. H. Khan asked about the status of the IBM 43P workstation that he had donated to CACTUS. John Christy has it and has installed AIX 4.3. There was some discussion about whether it can run later versions. Chris Boyd volunteered to stick it in a rack at Midas Networks.
Finally, Randy Zagar asked the membership if anyone was interested in bringing up the Open Solaris code on a CACTUS box. No one volunteered.
Randy then introduced Gil for the evenings VoIP demonstration. Gil Kloepfer gives a detailed report elsewhere in this newsletter.
And proving that God can occasionally reward the beneficent, Chris Boyd won the VoIP hardware raffle!
Thanks to Gil Kloepfer for the encore presentation, and to Lenny Tropiano for the successful raffle.
As you may remember from last month's newsletter, Bubba has been having hard disk troubles... Last month, Bubba wouldn't reboot automatically because its RAID controller felt that hard drive #2 was going to fail sometime in the near future...
I don't know about the rest of you, but I thought hardware RAID was supposed to let things operate normally AFTER a failure, not cause things to operate AB-normally before an actual failure occurs...
Tim Wood at Newisys was very helpful and provided a replacement drive for us, but the RAID controller wouldn't let me recreate the RAID mirror because it wasn't the exact same model as the original hard drive...
Ugh. This isn't the easiest RAID controller I've ever dealt with, but it's not the MOST difficult. IBM's ServeRAID controllers are the worst, but that's a story for another time...
Tim Wood at Newisys sent me a second hard drive, so we could have a matched set, and it's a good thing too, because now the RAID controller is complaining that drive #1 doesn't have long to live.
I guess it's a good thing we have that DVD-RW drive for doing backups...
At this point, I'm ready to pull Bubba out of the rack at Inflow and take it home for a complete overhaul. And while I'm at it, I think I'd like to upgrade the OS to Fedora Core 4. Among other things, this will give us all a chance to work with IBMs' Eclipse IDE... It comes standard with FC4.
Everyone should make plans for Bubba to be taken off-line on July 25th for extended maintenance.
One other thing: There doesn't appear to be any way for me to notify the membership that a system is going to go down for maintenance. I'd really appreciate it if this was on the agenda for the next meeting.
P.S. I'll be in Washington D.C. next week, so I guess I'll see you all again in August.
What happens if important CACTUS-related news happens between newsletter publications?
Well, before now the answer to this question would be, "Nothing." As discussed at our last meeting, on a trial basis the CACTUS Newsletter will include periodic "Newsflash" updates sent to those members who have subscribed to the CACTUS Newsletter mailing list (these will not be placed on the web site (right now) or posted to USENET news). In order to avoid being labeled a "spammer," our updates will be very infrequent and will include CACTUS board-approved notices of events or important newsworthy information that simply cannot wait for the next newsletter. Some examples of this would be the announcement of any ad-hoc "birds-of-a-feather" sessions, meeting cancellations, or supplementary material from a presentation.
The CACTUS board endeavors to have no additional mailings. We all understand that there's enough spam going around without CACTUS adding to that pile. A month is a long time in the computer industry though, and a well-placed update is sometimes necessary.
If you have any questions or concerns about this new feature, please contact the CACTUS Newsletter Editor (Gil Kloepfer) at kloepfer [at] cactus <dot> org.
During my presentation last month, there were several requests that were made by members that couldn't be easily answered during the meeting. I am hoping that as many of these as I can remember will be addressed here.
It is nearly impossible to answer this question because everyone has their own needs. For those getting started, the most cost-effective solution is one of the Sipura (http://www.sipura.com/ (now a Linksys/Cisco-owned company)) analog phone adapter. These can be purchased from companies such as Voxilla (http://www.voxilla.com/) for less than $100. These adapters support Caller-ID and distinctive ringing, among other features, are relatively easy to configure, and will interoperate with telephones you already have at home. There are also IP phones from Linksys/Sipura and Grandstream (http://www.grandstream.com/) that are inexpensive starter phones. Note, however, that the sound quality and/or features of the less expensive telephones are not as good as the more expensive ones, obviously. My favorite expensive IP telephone is the Polycom SoundPoint IP500-series (yes, the same Polycom that does the great speakerphones) that can be purchased for about $200.
You can also get great deals through EBay (http://www.ebay.com/). However, please be warned that some of these devices were obtained from a VoIP provider that has "locked" the configuration. Some of these cannot be unlocked and are useless. Always be careful when purchasing equipment from auction sites.
The best place for VoIP information is the VoIP wiki at http://www.voip-info.org/. There is a wealth of information here - more than you'll find on any static web site.
Of course, for more information from the primary developer and sponsor of Asterisk, Digium, you can visit their web site at http://www.digium.com/.
The person who recorded the voice prompts is Allison Smith (http://www.theivrvoice.com/). Allison has offered to record custom prompts for Asterisk through Digium's web site (this is under the PRODUCTS / Asterisk Extras / thevoice.digium.com selections on Digium's web site). The price for recording extra prompts is very reasonable, and people have had very positive comments about working with Allison.
In technical terms, what you are asking is, "How can I interface to the public switched telephone network (PSTN) with my Asterisk PBX?"
You may do this in one of two ways:
The first method is easy but does require you have a standard phone line and dedicate it (pretty much) to Asterisk.
The second method is usually what people are really asking for. There are numerous VoIP providers these days, kind of like ISPs were back in the day. What you need to look for is someone that will allow you to use SIP or IAX without the need for the provider to program your equipment. Vendors like this will typically market their services as "bring your own equipment" or will specifically say that they allow Asterisk with their service. Some providers that have this feature are Broadvoice (http://www.broadvoice.com/), VoicePulse (http://www.voicepulse.com/), and iconnectHere (http://www.iconnecthere.com/).
Jeff Pulver (http://www.pulver.com/) of PulverInnovations (http://www.pulverinnovations.com/) runs a service called Free World Dialup (http://www.freeworlddialup.com/) that is a free VoIP-to-VoIP relay service and does offer some gateways to other VoIP providers. Jeff's web site also covers a boatload of political topics surrounding VoIP.
All these are transport protocols for VoIP traffic. They all have their good and bad points:
Protocol: SIP [Session Initiation Protocol] (with RTSP)
Advantages: Well-supported, popular
Disadvantages: Doesn't go through firewalls well
Comments: SIP is good wherever you don't need a firewall, so SIP-based phones are a good choice. There are ways of getting SIP through NAT firewalls (STUN), but in general the RTSP part of SIP is one big hassle for firewalls.
Protocol: IAX [Inter-Asterisk eXchange]
Advantages: Works VERY well through firewalls, scales well for large numbers of simultaneous calls, is excellent for linking Asterisk systems
Disadvantages: Somewhat complex to administer, less supported and not as popular
Comments: Uses only port 4569/udp, so it's a good choice for NAT and all packet-filtering firewalls
Protocol: MGCP [Media Gateway Control Protocol]
Advantages: Somewhat popular, allows fine-grained control over telephone function
Disadvantages: Very complex to deploy on most phones that support MGCP, not as well-supported on Asterisk
Protocol: ITU H.323
Advantages: Somewhat popular, adheres to traditional telephony standards
Disadvantages: Very complex to implement, requires very complex libraries to use on Asterisk, extremely difficult (or impossible) to get through most lower-cost firewalls, being phased-out in favor of SIP
Protocol: Cisco SCCP [Skinny Client Control Protocol]
Advantages: Well supported by Cisco phones, provides more flexible control functionality than SIP
Disadvantages: Very Cisco-specific, not as popular, not well-supported on non-Cisco VoIP systems
Most modern PC systems run Asterisk fine. If you are not using specialized PC hardware that require drivers, you can use Linux and FreeBSD (among other) operating systems. The best driver support for the Digium hardware is on Linux, with beta drivers for FreeBSD. At CACTUS, we have demoed Asterisk on a Soekris (http://www.soekris.com/) net4801 system (266 MHz Geode with 128MB RAM). However, for more serious applications, or if you are using Digium hardware, you should have a minimum 500 MHz CPU speed and 256MB RAM. Digium has some recommendations for systems on their web site, and you'd be well advised to follow their recommendations if you want to use Digium hardware. On the FreeBSD-side, my only recommdation is to NOT use the ports system for Asterisk (at least to start) because it installs every contributed extension and requires far too many prerequisites.
Asterisk scales pretty well as the application is primary network-based. However, there are two important areas where the CPU is heavily involved: transcoding (changing audio from one format to another) and conferencing. Both of these perform DSP-like functions so a fast CPU (1 GHz or better) is a must.
Also note that while it would be a great thing to buy Digium hardware and support their Open Source development efforts, you can run Asterisk with no special adapters or hardware if you simply want to switch SIP or IAX calls. A fairly complete Asterisk system can be run using a Linksys/Sipura FXS/FXO SIP adapter and a pretty vanilla PC system running any Linux distribution.
I am maintaining (sort of) a web page at http://www.kloepfer.org/gc2/cactus.html/ with notes from my past CACTUS presentations. Unfortunately I haven't had a lot of time to update these and some of the information is out-of-date. As I have time available, I will try to make the notes current.
I would like to thank everyone who attended my presentation last month and Lenny Tropiano for providing the raffle that hopefully kick-started some interest in the Asterisk Open Source PBX. Because the presentation was driven by everyone who attended, we wouldn't have had such a great discussion without your questions and comments.
We would like to welcome Steve Young as the newest member of CACTUS.
We wish to thank Lindsey Haisley, Randy Zagar, Sherry Lesikar, John Helms, and Mark Scarborough for renewing their membership.
I would also like to make a correction to last month's newsletter: The contact information (phone number) for VoIPing, LLC was incorrect. Please see the sponsor list later in this newsletter for the correct phone number and e-mail contact.
To renew your membership, please send check or money order payable to CACTUS ($30/yr for regular membership and $100/yr for corporate sponsorship):
PO BOX 9786
Austin, TX 78766-9786
You can also pay in person at the general meetings. Please direct any inquiries or address changes to membership [at] cactus <dot> org.
CACTUS meets on the third Thursday of each month at the Applied Research Laboratories (ARL) in the JJ Pickle Research Campus (JJ PRC). We'll meet in the main auditorium located directly behind the guard's desk and main lobby.
Please do not show up earlier than 6:20 PM on the specified day. Enter through the main entrance at 10000 Burnet Road for ARL. Tell the guard that you are here for the CACTUS meeting. You will be required to sign a log book, but not required to wear a badge. The guards will direct you to the auditorium entrance. Limited parking in the front of the building is available, but more extensive parking is available in the large parking lot just north of the ARL building. After 6:30 pm, all entrances to JJ PRC, except for the Burnet Road entrance, are closed and locked. You can still enter the parking lot in front of the ARL building. No parking tags are necessary after 6:00 PM (but you will need to inform the guard in the booth that you are attending a meeting at ARL). See map for further details.
Online maps are available at:
As always, please leave the facility as you saw it when you arrived.