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

[Tzafrir Cohen]

On Thu, Mar 20, 2008 at 12:59:08AM -0400, Alex Balashov wrote:

> At the risk of inflaming a lot of passions, including those of 
> hard-working developers, I must say that where Asterisk may be 
> production-worthy, the entire constellation of things (like Zaptel) of 
> which its PSTN hardware interface capabilities comprise is absolutely 
> not, if my experience is at all telling.  Of course, that's not all 
> Zaptel's or Digium's fault;  much of it is just the buggy, flaky, and 
> very inconsistent nature of PC hardware, the kernel, ${insert true 
> culprit here}.
> 
> Nevertheless, my only truly solid experiences with Asterisk have come in 
> situations where it is used as a purely SIP agent.  FXO interface 
> hardware, PRI cards (Sangoma, Digium, Rhino, etc.) all have bugs, 
> strange interop problems I've never seen before with big iron TDM 
> switches or newer telco softswitches that generate those circuits, 
> bizarre apparent interpretations of certain ISDN messages, and can cause 
> system instability, lockups, etc. (Whether they are the true cause of it 
> or whether that's just a consequence of their interoperation with the PC 
> is unknown to me, and somewhat beside the point.)
> 
> They've come a long way, I think.  When I first used Digium T1 cards, 
> little, basic things like B channels not being hung up properly were 
> still a major and frequent theme.  For low-capacity installs involving 
> at most one or two PRIs, I think one may be all right at this point. 
> But I still think it's experimental and avant garde from a production 
> standpoint;  I find myself frequently stressing to my clients how much 
> better off they'd be just getting SIP termination and origination 
> elsewhere and breathe easier.  Sangoma seems quite all right.  Rhino is 
> OK, although as far as their multiport FXO interfaces go, it suffices to 
> say there is a difference between making it work and making it work 
> well.  Their free support does go a long way toward that end.  Your 
> mileage may vary.  Caveat emptor.

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.

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.
Also in this list. With Zaptel at least you have full ontrol of the
device

(disclaimer: I work for a Zaptel hardware vendor)

> 
> In general, though, almost any installation with any TDM trunking of 
> nontrivial volume is something in which I've ended up deploying 
> dedicated ISDN VoIP gateways, most recently Cisco AS5300s and 5400s.  In 
> general, this is what I would advise to anyone thinking about 
> terminating more than a handful of PRIs, let alone DS3s worth of 
> traffic.  Get proven, reliable hardware (even if it is expensive) from 
> vendors for whom TDM and carrier-grade telephony is a core competency. 
> I've seen far too many people try to take the cheap way out with a bunch 
> of Asterisk-oriented TDM hardware and not get quite what they were 
> expecting.  Don't do it.  There's something gravely perturbing about 
> running T1s into a PC anyway, although I know it's been done in certain 
> esoteric commercial telephony applications for eons.

Now please be specific about what is wrong with running a T1 into a PC.

I heard some people run Gigabit-ethernet into a standard PC. But maybe 
that also takes a dedicated cisco gateway.

Pre.S.: while writing this I wanted to link to Jim Dixon's article "The
History of the Zapata Telephony Project as it relates to the Asterisk
PBX". But it seems to have vanished off the face of the internet.
Anybody has a copy?

-- 
               Tzafrir Cohen
icq#16849755              jabber:tzafrir.cohen at xorcom.com
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http://www.xorcom.com  iax:guest at local.xorcom.com/tzafrir