dialogic was RE: [Asterisk-Users] "Glare" condition - How well does asteriskhandle?

[Steve Underwood]

Hi Scott,

Dialogic need a bit more than 1 50MHz 56001 per E1, as they do a modest 
echo canceller, and have a few bells and whistles in their tone 
detector. They don't have an awful lot, though. There is no reasonable 
codec they could implement, for example. A modest 2.4GHz Pentium is at 
least 50 times as fast as the 56001, if you do all the DSP in floating 
point (a Pentium tends to suck doing integer DSP).

Lets see. Early 90s would be ISA cards in an industrial PC chassis full 
of ISA slots. Heavy IVR means talking most of the time. 3k bytes/s per 
voice for the commonest 24K ADPCM mode most people use with Dialogic. 
So, 12 E1s is 360 channels. 3kbytes x 360 = more than the ISA bus can 
handle, before I even add up the disk loading. Does not compute.

On the other hand, how come you can only do 2 E1s of IVR with *? Lets 
take a modest single 2.4GHz Pentium. It can easily handle a lot of 
channels of voice playback. This is mostly disk limited, and even the 
slowest disk is much faster than the fastest in the early 90s. The DTMF 
detector takes almost nothing. You must be loading things up a lot with 
complex database and other activities you would never have dreamed of 
loading your old Dialogic machines with. The IVR part itself shouldn't 
be heavily loaded at just 60 channels.

Regards,
Steve


Scott Stingel wrote:

>Hi Steve-
>
>Not to belabor this, but the PCI version of the Dialogic DMV600 board has
>TEN 56311 DSP's per board - that's to handle only two E1's.  Having
>programmed the Motorola 56000 series DSP's in my past life, I can assure you
>that that's a fair bit of processing power.  In the "old days" (early 90's)
>with our own designs, we were able to do all the DTMF, as well as tone and
>voice detect for a 30-channel span with only one 50MHz 56001 DSP.
>
>http://www.intel.com/network/csp/products/7603ts.htm
>
>But real-world experience is more important.  The Digium TE4XXP boards can
>barely handle 4 E1's in one high-powered chassis (again, high volume IVR) -
>we used to routinely put 8-12 Dialogic-driven E1's in a single 300 MHz
>chassis with not a burp.  The signalling, protocol, call progress analysis
>etc are largely handled right on the Dialogic board.
>
>Anyway, sorry to run on about this..  I'm not knocking the Digium boards, in
>fact I support them exclusively now for new customers.   But to have the
>support of Dialogic boards available for people who want to build really
>large systems (or who have a ton of used Dialogics on hand) would be nice.
>
>Regards
>Scott Stingel
>
>
>Scott M. Stingel
>President,
>Emerging Voice Technology, Inc.
>Palo Alto California & London England
>www.evtmedia.com 
>
>
>-----Original Message-----
>From: asterisk-users-admin at lists.digium.com
>[mailto:asterisk-users-admin at lists.digium.com] On Behalf Of Steve Underwood
>Sent: Thursday, May 27, 2004 7:48 AM
>To: asterisk-users at lists.digium.com
>Subject: Re: dialogic was RE: [Asterisk-Users] "Glare" condition - How well
>does asteriskhandle?
>
>Scott Stingel wrote:
>
>  
>
>>Not to mention that the Digium T1/E1 cards are about 1/5 the cost of 
>>Dialogic's.  That said, it should be noted that the Dialogic cards 
>>allow scaling to a much larger size within one chassis, thanks to heavy 
>>DSP horsepower helping out with the low level chores.
>> 
>>
>>    
>>
>The Dialogic cards don't have heavy DSP horsepower. They have rather feeble
>DSP power. That is why they only do the simplest of tasks with the onboard
>DSP.
>
>Regards,
>Steve
>  
>