System information

It’s interesting to contrast the history of the telephone with the history of Linux and
the Internet. While the telephone was created as a commercial exercise, and the telecom
industry was forged through lawsuits and corporate takeovers, Linux and the Internet
arose out of the academic community, which has always valued the sharing of knowl-
edge over profit.
The cultural differences are obvious. Telecommunications technologies tend to be
closed, confusing, and expensive, while networking technologies are comparatively
open, well documented, and competitive.
Closed Thinking
If one compares the culture of the telecommunications industry to that of the Internet,
it is sometimes difficult to believe the two are related. The technology of the Internet
was designed in large part by academics and enthusiasts, whereas contributing to the
development of the PSTN is impossible for any individual to contemplate. This is an
exclusive club; membership is not open to just anyone.
†
Although the ITU is the United Nations’s sanctioned body responsible for international
telecommunications, many of the VoIP protocols (SIP, MGCP, RTP, STUN) come not
from the ITU, but rather from the IETF (which publishes all of its standards free to all,
and allows anyone to submit an Internet Draft for consideration).
Open protocols such as SIP may have a tactical advantage over ITU protocols such as
H.323 due to the ease with which one can obtain them.
‡
Although H.323 is widely
deployed by carriers as a VoIP protocol in the backbone, it is much more difficult to
find H.323-based endpoints; newer products are far more likely to support SIP.
The success of the IETF’s open approach has not gone unnoticed by the ITU. Since the
first edition of this book, the ITU has made all of the ITU-T and ITU-R recommenda-
tions available as free downloads in PDF form from its website (http://www.itu.int).
As for Asterisk, it embraces both the past and the future—H.323 support is available,
although the community has for the most part shunned H.323 in favor of the IETF
protocol SIP and the darling of the Asterisk community, IAX.
Limited Standards Compliancy
One of the oddest things about all the standards that exist in the world of legacy tele-
communications is the various manufacturers’ seeming inability to implement them
† Contrast this with the IETF’s membership page, which states: “The IETF is not a membership organization
(no cards, no dues, no secret handshakes :-)…It is open to any interested individual…Welcome to the IETF.”
Talk about community!
‡ Many people who are familiar with both protocols suggest that H.323 is in fact technically superior. Betamax,
anyone?
578 | Chapter 27: Asterisk: A Future for Telephony