[asterisk-users] Is Asterisk ready for Prime-Time?

[Tzafrir Cohen]

On Thu, Mar 20, 2008 at 06:45:14AM -0400, Alex Balashov wrote:
> Tzafrir Cohen wrote:
> 
> > Yeah, right. And we have no SIP compatibility issues at all. It is also
> > funny that you reflect the quality of old PRI card of one company and
> > yet ignore all the past mishaps of SIP devices.
> 
> Oh, no, I didn't mean to imply that.  There are plenty of SIP interop 
> problems with Asterisk as well.  I was actually just debugging a really 
> recondite one yesterday with MetaSwitch.
> 
> But nothing quite so dramatically abysmal as the TDM stuff.  Of course, 
> that could just be my particularly unfortunate experiences or 
> shortcomings;  I make no claim as to the universality of what I am saying.
> 
> > I have stared long enough in both PRI traces and SIP traces. Both
> > protocols are complex. I've seen very strange things happening with SIP.
> 
> Agreed, most certainly.
> 
> In fact, it's funny how often I've heard that SIP is a "simple" 
> protocol.  "Oh, you know, it's like HTTP, basically."  Um, no, simple it 
> is not.
> 
> > Now please be specific about what is wrong with running a T1 into a PC.
> 
> I don't have a lot of specific objections, as I am not a hardware 
> expert.  I was just commenting on what seems to work well and what doesn't.
> 
> If I had to speculate, there are backplane/bus throughput and timing 
> differences between dedicated, embedded TDM hardware chassis with T1 
> interfaces and PC motherboards with offboard cards.  One surely must be 
> more imprecise, inconsistent and replete with compatibility problems 
> than the other.
> 
> I could be very wrong.

PC hardware is produced in mass quantities. Hence you get hardware that
is much more powerful. PCs today have hardware that has basically all
the required CPU to handle quite some traffic.

PCI (and even USB...) has been shown to be good enough to pass T1-s.
Even with the unoptimized high interrupt rate of Zaptel. There's plenty
of room for improvements in Zaptel. But people live with it right now
because the CPUs we have are powerful enough.

> 
> > I heard some people run Gigabit-ethernet into a standard PC. But maybe 
> > that also takes a dedicated cisco gateway.
> 
> Ethernet is a data animal, not a synchronous voice animal.
> 
> But then, a goat is not a synchronous voice animal either.

One main application is getting that synchronous voice over to voip. For
that applicaiton we can easily afford adding a few delays.

Now what happens when you actualyl want synchronous voice? Faxes?
Modems? You could choose to of-load all of that to the dedicated
gateway. But why?

-- 
               Tzafrir Cohen
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