[Asterisk-Dev] Henning G. Schulzrinne quote on IAX2 from von magazine

[Steve Underwood]

Mike Taht wrote:

> but hey, maybe the folk on this list understand where he's coming from 
> and can explain why sip is better....

He is one of originators of RTP and the main guy behind SIP. Of course 
he thinks they are wonderful. The reality is they were both poorly 
thought out, and people have been shoring them up ever since.

RTP used endless ports for no good reason. Nothing was symmetric. 
Bandwidth was considered of no consequence. It had no security, which 
has only recently been grafted on with sRTP. People have put massive 
effort into trying to live with or fix these things ever since.

SIP started from the notion that call control is fundamentally simple, 
and H.323 was overly complex. SIP has been getting more complex ever 
since, and is now as complex as H.323. It had no security, and used an 
unreliable medium (UDP) for communication that needs to be reliable. Now 
networks are changing this, through a massive overhaul. To his credit 
Henning does accept that UDP for SIP was a dumb idea.

He does say some good things, like:

"I consider the term "soft switch" a marketing term that, like its 
cousin, "session border controller," seems to have no crisp definition 
that everyone can agree on. Even the Soft Switch Consortium has changed 
its name. The sooner we can drop the term soft switch from our 
discussions, the sooner people and their PowerPoint presentations will 
actually have to explain what their architecture is, rather than hiding 
behind an ill-defined label."

Of Skype "Most importantly, Skype got the "out-of-the-box" experience 
right-most of the time, it just works, without complicated 
configuration, even with NATs."

and "One of the nicer things about Skype is that they avoid being 
trapped in replicating the PSTN user appearance. Others have tried to 
make their software applications look like a cell phone or desk phone, 
which most often simply causes the software to inherit all the usability 
limitations that ISDN and other feature-rich phones had. A user 
interface stressing the buddy list and IM functionality seems a much 
better fit. "

and "Also, they provided higher-quality audio codecs rather than feeling 
constrained by the notion that this would be wasted since the PSTN only 
supports narrowband audio. The technology to do this is fortunately 
readily available, both commercially and as open-source codecs like 
Speex, and SIP-based soft clients such as the new Yahoo Messenger and 
EyeBeam."

He doesn't seem to really understand the strengths and weaknesses of 
IAX. IAX has drawbacks, but none of the problems he lists actually exist.

Regards,
Steve