Splitting a T1
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Thread: Splitting a T1

  1. #1
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    Splitting a T1

    Hey guys, I have a question for you.

    I'm gonna help set up a T1 at my grandpas business, and I was wondering if there was some sort of software out there that would monitor things such as Number of phones on line, and number of active ccomputer connections. What I need this software to do, is continually give the most available bandwith to the computers, but when more phones come on, then it needs to direct more bandwith for the phones. You see what I'm saying?

    When theres not that many phones being used I want more data throughput for the computer, but when theres more phones on, I need more throughput for the phones. Is that possible?
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  2. #2
    AO BOFH: Luser Abuser BModeratorFH gore's Avatar
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    Well, the 24 channels in a T1 line are managed by a Time Division Multiplexer (TDM), which divides the channels into time slots. Each time slot can be used to carry a different phone call or data circuit. Each phone call or data cuircuit is allocated 64 Kbps. Time slots can be allocated in a variety of ways. For example: There might be 12 time slots for voice, 6 time slots for for data, and another 6 for video conferencing.

    Depending on what kind of business your Grandad is opening you may not need any for video conferencing. At the end of every T1 line is a Channel Service Unit (CSU). The CSU is the demarcation point from the telco to the customer. This provides the termination for the digital signal.

    The CSU converts customer data and voice signals into the format needed by the telco for transmission. The telco uses the CSU for diagnostics test and so on to make sure of how the connection is working.

    The CSU also keeps the line connected if the communications equipment fails. A CSU can be built into a router or into multiplexing equipment. As for monitoring traffic, I think something like IPTraff should do fine for most of it.

    Sorry I cant help a little more, but I did include a screen shot of a bandwidth test I just did.
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    AO BOFH: Luser Abuser BModeratorFH gore's Avatar
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    This test and the one above are with a router and 4 computers hooked up on this connection.
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    Thanks for your help Gore,

    Well we won't need any channels for video, so we'll have more bandwith for the phones and Data. There would probably be about 15-20 phones hooked up, Whatever the phones don't use, we would use for the internet.


    So say we have a total of 20 channels, and we have 15 channels for the phones and only 5 for the computers to get on the internet. If the phones are only using 10 out of the 20 channels that they have, can those extra channels be transferred over to be used for the internet, then transferred back to the phones again, once they are needed.?

    i've attached a little diagram I drew up. maybe you can see more clearly what I'm needing.
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  5. #5
    AO BOFH: Luser Abuser BModeratorFH gore's Avatar
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    That may be an option. Whatever company you are using for your service, should have that as an option. Usually you can say something like "Ok, during this time of day we may need more phones, or more data, can we switch between this?"

    Just ask them and they can give you a for sure answer. It's possible, but may depend on the company.
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    I was wondering about this, cause the first people I talked to told me I could not switch use one T1 for both phone, and data, but I always thought you could. They are running all the wires right now in the offices, but I haven't been up there in forever. I guess I can call them up and see what they say.

    I was pretty sure that you could split the T1, but I wasn't sure if you could change the number of channels available from using a piece of software. Something that would monitor the usage of the T1 and allocate channel where neccessary.

    Thanks for your help Gore.
    =

  7. #7
    AO BOFH: Luser Abuser BModeratorFH gore's Avatar
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    No prob man. We discuss stuff like this is both of my classes like all the time. I have my WAN class and my TCP/IP class right now, so we talk about networking all the time. But yea, calling them up should solve it. Unless I misunderstood something, you can actually allocate for phone lines as needed if you get a deal going with the ISP.

    If you can't though or they say no, then I'm sorry, but hey, it's worth a shot
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  8. #8
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    lol.

    yeah I'll give it a shot.

    I'll post back after I know the answer to this.
    =

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    You would need to split your channels out at the CSU/DSU level before you get to your router. Unless the CSU/DSU is on your router. If you are interested in splitting voice/data over one connection, you would be better suited to do so on An ISDN. This way you could benefit from caller ID. Just a suggestion.
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    You can split the channels for voice and data, but you would need a multiplexer (essentially a multi-port CSU). And your circuit needs to be setup and delievered a certain way for you to do that. The way the circuit was ordered might not allow you to do that. Whoever sold you that circuit should be able to answer that, or you could try calling your Telco.

    I might have mis-understood the question, but a computer or phone will not take up one channel on the T-1, nor can the computers use the unused voice channel.

    basically if you have 5 channels for data, that's 320Kbps and 19 channels for voice (1.2Mb) then that's it. Your computers basically will have a 300Kbps line to the internet and your phones have 1.2Mb. IMHO, you should be fine with 256 or 384 for your phones. (4 and 6 channels respectively) and use the rest for data. This obvisously depends on your phones and the CODECs they use (ie. G.729, G723.1 or something else)

    Hope this answered some of your questions.
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