Big practical systems

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Asterisk Users 10 Comments

I don’t want to start the “How many calls can Asterisk handle?” discussion
or “How many angels can stand on the point of a pin?” discussion either.

But can anyone contribute some practical knowledge of systems that take in
channel bank T1s or DS3s from “far away”, and process the calls?

I am looking for real world, been there, done that, or “check the ‘Belchfire
Systems GigaFiber 65536′ system”.

Not to start the discussion, but “Is there a board that will take a DS3 (672
channels) and a system that will handle the calls, or is that a silly
question?”

Is there an IP box that would take the DS3 and then a system that would
handle the calls? My guess would be yes because the actual call load would
be far lower than 672 calls. Maybe 100-150 or so simultaneous.

Each line/call would have to have absolute caller ID. In other words, PSTN
call handling.

Cary

10 thoughts on - Big practical systems

  • inline

    You just did

    Most of us are far too busy. These things are best learned the hardway.

    Its called Asterisk.

    There are many. The primary problem it getting a provider to provide
    you with a DS3.

    There are a few solutions here and several expensive chunks of
    hardware. Do you want to put all your eggs in one basket?

    That is between you and the provider. The technology exists on the wire.

    Gringo Malvado…

  • Alternate question:

    Asterisk/PSTN oriented.

    If an Asterisk system were interfaced via a T1 to a local telco loop to a
    customer premises:

    (This is not a T1 to the customer premises, but a T1 to the telco who then
    demuxes it to copper to the customer premises. IE. In Telecom terms an
    EEL.)

    Will Asterisk handle that scenario with common drivers and cards?

    Who generates the customer audio “comfort sounds”, ringing, busy, etc?

    Cary
    “I know a lot, but not everything.”

  • I believe this looks like a standard channel bank. Asterisk generates all audio. Ring and hook status are sent out of band. Dial tones are in-band. Ringback, busy, congestion are in-band audio. I would think a standard T1 card would be fine.

    That said, I would verify this with the LEC.

  • Yes. Adtran makes excellent gear. The MX 2800 is good for breaking a
    channelized DS3 into PRIs.

    If by board, you mean PCI board for shoving in something with an intel
    cpu, not that I’ve ever heard. Digium sells 4x port PRI boards, and
    some competitor sells an 8x port PRI board, but I’ve never tried any
    boards not made by Digium.

    The only thing silly is the idea of trusting that many calls to PC hardware.

    Yes, embedded hardware from a vendor you’ve heard of will do that.
    Cisco makes a 3845 which can terminate about 20 PRIs in one appliance.

    Well, then it’s not really a DS3. If it can’t do the whole thing
    without melting down, it shouldn’t advertise itself as DS3. The Adtran
    gear works rock solid when pushed to the limit.

    If you’re just talking 150 calls, you could do that with two 4x port
    cards in a single PC. I thought you were talking a lot bigger.

    Ummm, there’s no such thing as absolute caller ID. You wanna try that
    question again? callerID is not legally binding, is not used by
    billing, anybody can spoof it.

    The closest you can get is to have a LEC provide ANI. You don’t need
    PRI to get that. You can get that via a quality voip provider, or
    yourself using your own termination gear to convert into voip.

  • Yes. Adtran makes excellent gear. The MX 2800 is good for breaking a
    channelized DS3 into PRIs.

    ====> Thanks, will look at that. Ah, a DS3/T1 mux. I was looking for a DS3
    PC Card… it would have 672 “channels” but the system doesn’t need to
    handle but “<20%" of them at one time.

    If you're just talking 150 calls, you could do that with two 4x port
    cards in a single PC. I thought you were talking a lot bigger.

    ======>I mean DS3 with 672 channel paths. There are 672 subscribers “out
    there”. I am saying that only a percentage of them are talking at peak
    times. We need to “supervise” 672 lines and expect 15% to talk at the same
    time.

    PSTN

    Ummm, there’s no such thing as absolute caller ID. You wanna try that
    question again? callerID is not legally binding, is not used by
    billing, anybody can spoof it.

    =======>I mean we have to provide service and know what line is calling, not
    just provide anonymous service to a lot of people. We can’t just mux a
    bunch of lines in to the Asterisk box with no identification.

    Cary

  • It won’t be ISDN. It will be some form of RBS. You probably have several
    choices as to which type of RBS (probably several ESF options, you’ll
    probably pick one of them; you may be able to use SF as well).

    You should probably work with your LEC to figure out exactly what they will
    hand off to you. You might make a costly mistake if you don’t.