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Subject: SIP in higher education

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VoIP SIG + call minutes - May 17, 2007

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  • From: Garret Yoshimi <>
  • To: Internet2 VoIP SIG <>, "Internet2" <>
  • Subject: VoIP SIG + call minutes - May 17, 2007
  • Date: Wed, 20 Jun 2007 13:51:49 -1000
  • Organization: University of Hawaii

Hi folks,

Apologies for the delay in these notes from our last call (and the abbreviated list of attendees since I was slow in starting the recording); I'm catching up on my e-mail piles after being on the road for a couple of weeks.

We have a couple of topics in the queue for the summer; please feel free to suggest speakers or topics for future calls.


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Notes for VoIP Conference Call - May 17, 2007


Chris Casswell, MCNC
Todd Edwards, Wake Forest
Dave Laurentino, Research In Motion
Deke Kassabian, University of Pennsylvania
Candace Holman, Independent
Phil Kulick, Penn State
Jonathan Tyman, Internet2
Chris Trown, University of Oregon
Garret Yoshimi, University of Hawaii
... and several others ;-)


Today's call features Bill Rich, the president and CEO of Pingtel, providing a overview of open source SIP software. Bill starts by talking about a recent survey that he completed for ACUTA on VoIP deployment, which included a question about open source. The results indicate that while a large number of respondents are considering open source applications, 54% are not. A similar survey from three years ago indicates that there are greater numbers of people interested in open source now. Bill feels that this is representative of the early state of VoIP deployment, where people are starting to experiment but have yet to fully investigate open source options.
Bill talks about the Internet 2 reference architecture for VoIP, which he feels is a strong intersection between open source communications and VoIP. The reference drives what he calls the decomposed model, which allows organizations to build their own solutions using best-of-breed components in a vendor-neutral manner. This enables groups to deploy services at their own pace and encourages innovation at every level of the chain. Call control, networking, applications, and devices can all be configured and combined in ways that were previously impossible and in a manner that is diametrically opposed to the traditional TDM hierarchy, which focused on tightly integrated single-vendor solutions. This traditional approach, in Bill's opinion, offered limited flexibility and innovation as well as elevated costs. The arrival of open source communications systems has led to systems based on standard protocols with more choices for handsets and applications, as well as lower costs and quicker development cycles. Bill notes that some traditional vendors are developing VoIP solutions, but they are still based on the single-vendor models and often use proprietary or modified protocols, closed software, and limited choices for hardware.

One key element of open source is that the software is freely available. Customers can set up and configure the software on their own at no cost, or purchase supported versions for lower cost than traditional software. The open nature of the software leads to faster development and more innovation. Bill notes that there are several myths regarding open source, which he debunks. The open nature of the software leading to security risks is one such myth; the idea is that since anyone can contribute to the code it is easy to add malicious code. In reality this is unlikely, as projects are centrally managed and contributions are examined thoroughly before being integrated.

Another myth is that the software is of lower quality since it is free and nobody makes money from developing it. In reality, most large open source applications are funded by companies who pay developers and perform QA work on the resulting software, often indemnifying customers to ensure trust.

A third myth is that using open source software ends up being more expensive due to development and support costs. Bill notes that most major open source applications are available as commercial packages with support, and users are only on their own if they choose to be. Management tools for open source software have also gotten quite good, with most offering GUI applications rather than the traditional command-line interfaces.

Bill discusses the two major open source SIP projects: SIPfoundry and Asterisk. SIPfoundry is an IP PBX application sold as a commercial product by Pingtel and meant to serve as a unified SIP-based communication core, using SIP terminals and extensions. The SIPxchange software is sold by Pingtel on a subscription model, where customers pay a certain amount per server per year, up to a particular number of users. At the end of the subscription, the organization can continue to use the software at no cost, but would lose support. Pingtel performs a variety of testing and integration work with third party phones and gateways, and employs most of the SIPfoundry developers. The product is available as software only or as a complete package with all necessary hardware, handsets, and servers.

The other major open source SIP product is Asterisk, which has been around for close to seven years and is widely known and used. Asterisk is popular with a number of small businesses, though there are plenty of larger deployments as well, and is often used as a stand-alone voicemail application. It is mainly commercialized by Digium, whose business model focuses on selling cards to work with Asterisk. Other open-source packages mentioned by Bill include SER, which is a SIP router, and FreeSWITCH which is an outgrowth of Asterisk.

Bill offers a real-world example of costs for Pingtel's SIPxchange ECS product. For 25 users, with hardware, a media gateway, the SIP server, Polycom 430 phones, and a software subscription, including installation and support, the cost would be $300 per seat. Moving up to 200 users brings the cost down to $258 per seat, which is very cost effective compared to traditional solutions. Bill also notes that the major cost is for the IP phones, with the Polycom offered as a very middle-of-the-road solution. The real question, he says, is if the open-source SIP solution is ready for deployment in mission-critical applications. Bill feels that this answer is a definitive yes.

All of Pingtel's software goes through traditional software development practices, with releases in phases, QA, and faster release cycles of three to four months. The majority of common features from other communications software are available, as is support, a suite of management tools, and the ability to integrate with technologies like SOAP and LDAP. Current customers include a variety of colleges with deployments from 500 to 2000 users, with plans to scale to 3000 total. Amazon is also a customer, running their Seattle offices on Pingtel systems. Bill says that there is probably a limit of about 10,000 users on one server, but at a cost of $5,000 to $7,000 per server it is not difficult to add more servers while remaining less expensive than traditional systems.

Susan from Boston University asks about security measures in SIPxchange. Bill says that both products incorporate TLS, and secure SIP signaling and media available by the end of 2007.

Deke from Penn asks about the ability to do bridged line appearance and busy indicator across multiple lines. Bill says that BLA is available in SIPfoundry 4.0, which is scheduled for the end of summer and will work across differently phone types. Certain phones will things slightly differently, and initial support will probably be for Polycom and SNOM phones.

Garret asks about installations for over 10,000 users. He's seen a lot of deployments in the 100's and low 1,000's, but asks if anyone is seriously looking at 30,000 to 40,000 line implementations. Bill believes that this is the case, but would like to qualify his statement. There are currently live implementations of greater than 5,000 lines, and he's confident that 10,000 would work on high-availabiltiy load-balanced servers. There is also work done on isolating specific aspects, such as media or call center loads, onto different servers. In lab tests these systems can handle 20 to 25 calls per second, so two or three systems would work for 30,000 people. Voicemail and dialing plans are another concern, but it's possible to have multiple systems using one voicemail system.

Finally, Bill is asked about E911 support and lawful intercept. He says that E911 is supported, but lawful intercept currently is not as in the past it has been thought of as happening once traffic has moved to a public network. He understands why this would be desirable, though, and says that it is being worked on.

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  • VoIP SIG + call minutes - May 17, 2007, Garret Yoshimi, 06/20/2007

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