[asterisk-users] Where is the Digium DS3 card?

[Alex Balashov]

Steve Totaro wrote:

> Nobody said anything about unused DS1s except you.  Please re-read the thread.

Perhaps I misunderstood?

What you appeared to imply in regards to the failover benefits of having 
T1s broken out of an M13 mux into multiple gateway machines is that if 
one of the gateways go out, calls can go roll over to other PRIs in a 
trunk group.  That suggests that there are unused PRIs with some sort of 
substantial leftover capacity.

My point was that if you got enough capacity just sitting there to 
really make this an economical enhancement from the standpoint of 
managing statistical loss expectancy on a DS3 meaningfully, I am brought 
to ask why to get a DS3 in the first place.

> A cold Adtran MX2800 M13 spare is a good idea, isn't it?

No controversy there.

>>  It all depends.
> 
> On who you know.

Most definitely, but far from always the sole determinant.

> Yes and when your commercial grade VoIP gateway fails, you have
> NOTHING.  I am still up and running just to a lesser degree.

But that's why one keeps a cold spare around, right?

The axial thesis here is that if your uptime requirements are so tight 
that you can't afford to be down for the time it takes to swap to a cold 
spare gateway, and your chosen strategy to mitigate that is to use a 
bunch of PCs with T1 cards, then there's a lot upside down here and 
you've got far bigger fish to fry anyway.  From a risk management 
standpoint, not necessarily any other.

But that's the essence of the polemic about uptime, is it not?

>>
>>  This is true, PCs are easier to deal with when they fail.  No question
>>  about that.
>>
>>  On the other hand, Cisco AS equipment is that much less likely to fail.
>>   Keep one cold spare around and you're good.
>>
> 
> Please provide citation of your "facts"  And when it does fail, then
> what?  Total outage.  Instead of losing $1k/hr you are losing $26k/hr

I don't have MTBF data on various equipment.  Much as you do, I simply 
furnish you with the narrative of my empirical experience;  I've seen 
lots of PCs die, lots of Digium/Sangoma/etc. cards die or perform 
poorly, and I'm yet to see any Cisco voice chassis I administer die. 
I've got some with 4+ year uptimes.

I'm sure it's coming soon.  :)

> Well all I can add is that I installed the system outlined above and
> have had zero trouble with the TDM->SIP servers at all in over two
> years.  This is a multimillion dollar company and it works flawlessly.

Perhaps you are onto something, then.  I would say you're extremely 
fortunate whether you are or not.  That has not been my experience, and 
that is all I can attest to, really.

> 
> BTW, thanks for taking down the the article you wrote by reverse
> engineering my work and claiming you did it all and announcing it to
> the list.  That was really shady.

As mentioned before, I did not reverse engineer your work.   I 
documented the standard approach to the Asterisk/Hylafax problem, oft 
repeated in many places, of which your implementation -- which I have 
indeed seen -- was a good example.

Feel free to e-mail me off list any suggestions you have as to what 
aspects of my article infringe upon any idiosyncratic or proprietary 
aspects of your work or your implementation in particular, and I will be 
more than delighted to work something out with you.

Thanks,

-- Alex

-- 
Alex Balashov
Evariste Systems
Web    : http://www.evaristesys.com/
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