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

[Steve Totaro]

On Mon, Apr 7, 2008 at 10:46 AM, Alex Balashov
<abalashov at evaristesys.com> wrote:
> Steve Totaro wrote:
>
>  > 7 HP DL320s, RAID 1 with Quad Sangoma.  Not a dozen but more than
>  > twice that, 28 T1s.  What is your cheaper solution?  Also, have two
>  > cold spares in the rack.  DL 320s are cheap and "rarely fail" using
>  > 1.2.X.  I actually cannot remember a single failure over years of
>  > operation.
>
>  My solution, if we may call it that, is certainly not cheaper.  It is
>  not always about price.  There's that whole value thing, too.  :)
>
>  The point I was trying to get at earlier is that if one has unused DS1
>  carriers on a DS3 and you are debating extra cold-spare PCs with T1
>  cards to provide failover in a PRI hunt group because one literally
>  cannot afford downtime at the statistical incidence typically incurred
>  by the failure of industrial DS3 interface equipment, one is probably
>  chasing their tail and needs to rethink one's strategy at a much higher
>  level than simply the question of terminating equipment.
>

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

Cold spares are good to have around, how can you not argue that fact.
Rather than take a box out of a rack and spend however long it is
going to troubleshoot it, you can pop the cold spare in and be up and
running in the amount of time it takes Linux to boot and change the IP
and a couple of other settings, then return to the dead box.  If it is
that level of redundancy is good enough for Computer Science
Corporation, it is good enough for me.

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

>
>  > I don't think you have much experience with DS3s, correct me if I am wrong.
>
>  I do.
>
>
>  > While pricing many solutions, it is either 14 or 16 T1s where a DS3
>  > becomes about the same cost for the loop, that is a lot of wiggle
>  > room.
>
>  A bit of a digression, but:
>
>  That is commonly the case, indeed, with "many solutions."  It is also
>  commonly not the case.  Sadly, this topic lends itself to generalisation
>  not;  if it did, our lives would be considerably simplified and a
>  marketplace rationale value chain consisting of a whole slew of agents,
>  resellers and brokers would cease to exist.
>
>  It all depends on who the transport vendor is, if it's an ILEC, and if
>  so, which ILEC, which LATA, applicable tariffs, forebearances, whether
>  there is inter-CO mileage, etc.  If it's a CLEC, it's a question of
>  whether there are blacklisted COs in the span design, the price of their
>  CFA.  If it's a retailer of Bell services it's all a question of what
>  kind of pricing and options _they_ get, and whether the DS3 is delivered
>  over regulated, UNE-subject copper, etc.
>
>  I have been in situations where it is more economical to get a DS3 after
>  about 5 T1s because the DS3 was built over leased utility dark fibre in
>  a metro area.  I have also been in situations where even 20 T1s are
>  cheaper than a DS3 loop because of the particular facilities and various
>  pricing/tariff absurdities that are so characteristic of ILECs.  I have
>  also seen on more than one occasion where a stupidly large number of
>  distinct analog lines (as in, pairs all the way from the MDF, not even
>  GR.303/DLC-delivered stuff!) was cheaper than using T1 as a carrier for
>  an equivalent number.  Something about USF subsidies in rural areas
>  *cough* *cough*.
>
>  It all depends.

On who you know.

>
>
>  > Read the specs on the Adtran 2800 MX13.  I don't think it is going to
>  > fail unless you smash it or pour coffee on it.  Google it and RTFM
>  > before you spout off about a product you obviously have no knowledge
>  > of.
>
>  I have used the Adtran M13 muxes, and I postulate nothing about them
>  save that it has the common liabilities of all electronic devices
>  composed of matter and compliant with the laws of physics and the
>  discovered properties of the known natural universe.  They can and will
>  break.
>
>  No, seriously, I agree -- be it an Adtran or a Widebank or whatever,
>  it's pretty hard for an M13 mux to blow.  It's almost something you have
>  to really want to happen.
>
>  But do realise the sort of equipment toward which I am gesturing is
>  engineered to a similar level of reliability, proportionally, as much as
>  is possible in light of increased complexity and composition.
>
>
>  > We are talking DS3 here, not OC12.  Talk about overkill.
>
>  What is fundamentally different?  Both are used as transport facility
>  for high-density inter-machine trunking.  One does not need native SONET
>  to have a need for extremely high TDM circuit availability.
>
>  No, you do not need the level of redundancy I am suggesting in the sort
>  applications being discussed.  That's the whole point.  If, on the other
>  hand, you do, to the point where you're fretting about a DS3 interface
>  on a commercial VoIP gateway failing vs. having a bunch of PCs with
>  broken-out T1s, then it might be worth the investment to overengineer in
>  a manner that corresponds to telco environment requirements.

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

>
>
>  > They are essentially small servers, some with solid state and flash,
>  > others with real hard drives.  Ever open one up?  I would prefer to
>  > pop a case and replace a T Card, memory, hardrive, powersupply, fan,
>  > then waiting on an RMA.  Especially when your call center is losing
>  > $26k an hour.
>
>  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

>
>
>  --
>  Alex Balashov
>  Evariste Systems
>  Web    : http://www.evaristesys.com/
>  Tel    : (+1) (678) 954-0670
>  Direct : (+1) (678) 954-0671
>  Mobile : (+1) (706) 338-8599

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.

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.

Thanks,
Steve Totaro